DCA25-150 Service Manual - Multiquip Service & Support Center

DCA25-150 Service Manual - Multiquip Service & Support Center
SERVICE
MANUAL
®
DCA 25-150
GENERATORS
SCHEMATICS ○ TEST PROCEDURES ○ TROUBLESHOOTING
DCA - 2 5 1 5 0 - CD
Manual No. DCA25150CD
CALIFORNIA
Proposition 65 Warning:
Engine exhaust and some of its constituents, and some dust created by power
sanding, sawing, grinding, drilling and other construction activities contains
chemicals known to the State of California to cause cancer, birth defects and
other reproductive harm.
Some examples of these chemicals are:
•
•
•
•
Lead and lead-based paint.
Crystalline silica from bricks.
Cement and other masonry products.
Arsenic and chromium from chemically treated lumber.
Your risk from these exposures varies, depending on how often you do this type
of work. To reduce your exposure to these chemicals: ALWAYS work in a well
ventilated area, and work with approved safety equipment, such as dust mask
that are specially designed to filter out microscopic particles.
2
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
IMPORTANT!
Read the operator's manual for safety instructions before you attempt to troubleshoot. Use extreme
caution when troubleshooting power equipment. Never start or run power equipment inside a closed
area, breathing exhaust fumes can kill.
Basically, a tool is an object that enables you to take advantage of the laws of physics and mechanics
in such a way that you can seriously injure yourself.
This service manual is intended to provide information and procedures to safely maintain, repair and
give a basic understanding of service techniques for the DCA series generators.
You must be familiar with the operations of the DCA series generator before attempting to
troubleshoot or make repairs. Basic operating and maintenance procedures are described in the
operation and parts manual supplied with the generator. Use the supplied manual to order
replacement parts. If you are missing the operation and parts manual, please contact Multiquip Inc to
order a replacement or you may visit our website at www.multiquip.com
For your safety and the safety of others carefully read, understand and observe all instruction
described in this manual.
Safety precautions should be followed at all times when servicing
equipment. Consult operations manual for more safety information.
THE INFORMATION CONTAINED IN THIS MANUAL IS BASED ON DCA-SERIES GENERATORS
MANUFACTURED UP TO THE TIME OF PUBLICATION. MULTIQUIP INC. RESERVES THE RIGHT
TO CHANGE ANY PORTION OF THIS INFORMATION WITHOUT NOTICE.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
3
CONTENTS
Generator Inspection …………………………………………………………………………….…..5-6
Maintenance Inspection List …………………………………………………………………………..7
Component Identification …………………………………………………………………………..8-10
Generator Specifications ……………………………………………………………………………..11
Troubleshooting ……………………………………………………………………………………….12
Frequently Asked Questions …………………………………………………………………………13
GENERATOR COMPONENT OVERVIEW
Gen-Set ………………………………………………………………………………………………...14
Rotating Rectifier / Surge Protector .……..………………………………………………………….15
Automatic Voltage Regulator ………………………………………………………………….……..16
Gen-Set Data ……………………………………………………………………………………..……17
Voltage Selector Switch …………….……………………………………………………………..18-20
Open Delta / Rheostat Data ……………..………………………..………………………………….21
Main Circuit Breaker / Amperage Rating Chart …………..…………………………………….…..22
Over Current Relay ………………………………………………………………………………..23-24
EDUCATION
Index …………………………………………………………………………………………………...25
ENGINE CONTROLS
Index …………………………………………………………………………………………………...36
WIRING SCHEMATICS
Index …………………………………………………………………………………………………...49
GENERATOR GLOSSARY
Index …………………………………………………………………………………………..……….78
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Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
GENERATOR INSPECTION
Before you attempt to diagnose a generator problem, check the engine to make sure that it has been
serviced and is operating correctly. Perform proper maintenance and tune-up procedures before evaluating
the generator. Ensure the engine remains at a stable rpm when electrical loads are applied.
When servicing generators having an accurate AC/DC multi-meter is a must
The first step in generator troubleshooting is to conduct a visual inspection before doing any electrical tests.
Looking the generator over carefully should expose any environmental factors that might contribute to the
problem. As you remove the generator control box cover and begin your inspection, look for the following:
1. Rusted or corroded connections. An oxidized connection will prevent the circuit from being completed.
This applies not only to the major cables externally, but also to the electronic control devices internally.
2. Carbon flash deposits around the 120V AC and 240V AC receptacles. This will indicate whether the
device that was plugged into the generator shorted out the receptacle. The device may have shorted the
generator to ground and caused a carbon flash when the plug prongs touched the receptacle.
3. Signs of overheating. Discoloration and a burnt smell should be noticeable inside the generator. Look to
see if the windings turned black. The winding insulative coating may vary in color from shades of reddish
brown to light brown to dark brown, so try to compare the color to that of a new unit.
4. Wire insulation that is hardened from heat exposure. Fabric and plastic insulation hardens over time due
to heat exposure and overheating. Long-term heating should be more uniform. A short, excessive heat
cycle may have less hardening and burning on the outer perimeter and excessive heat signs toward the
center or heat source.
5. Insects that have developed a community inside the generator. Their nests and debris can cause
electrical shorts. Generators left out in the elements, such as for running water wells, provide a nice
home for critters such as spiders, wasps, and mice.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
5
GENERATOR INSPECTION
• continued •
6. Loose bolts, screws, and fasteners. This condition will either prevent full-time service or give intermittent
service depending on the situation.
7. Problems in quick disconnect connectors. These are often overlooked. A quick disconnect could have
one to a dozen male-female connections. These are often inside some plastic or rubber cover that
prevents you from seeing any possible corrosion. In electrical troubleshooting, always unplug and plug
in all connectors three times to produce a freshly scraped metallic surface for good electrical contact. If
the unit works after that, soak the connectors first in vinegar for a few minutes, then in a baking soda
solution. Rinse the connectors thoroughly with distilled water. This acid/base wash will remove
corrosion, but not oil or grease. Blow dry thoroughly. Using an ohm meter, check for zero ohms on all
connections. Spray the contacts with an electrical insulative spray before reassembling them.
8. Crimp connections: Even though they're widely used, they can become loose as the machine vibrates
and lose consistent quality contact. Because dissimilar metals are in contact, a galvanic cell is set up
that may result in corrosion when moisture is present.
9. Solder joints that have cracked or broken loose. This condition occurs much less frequently than
crimped connections and basically results from poor-quality workmanship.
10. Worn insulation allowing wires to short. Insulation deteriorates from physical contact when wires rub
together due to vibrations. Eventually, the internal wires can short to each other or to ground.
11. Crossed wires: Mistakes happen, particularly if the unit comes from another shop with unresolved issues
or you receive it partially disassembled.
12. Fuses, circuit breakers, and ground fault interrupts. Check for physical damage to housing, buttons and
levers.
6
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
MAINTENANCE INSPECTION LIST
The following is a compiled list of duties performed by service technicians, most of the tasks should be done
during normal scheduled maintenance.
INSPECT:
Air cleaner for restrictions and contaminants - replace if necessary.
Coolant concentration and level - adjust to 50 / 50 mix or as recommended by engine manufacture.
Cooling system hoses for cracks and distortions - tighten clamps or repair as needed.
Radiator for restrictions and corrosion.
Block heater for leaks and is functioning properly, (this is an accessary on most units).
For coolant, fuel and oil leaks - tighten connections or repair as needed.
Belts and pulleys for cracks and wear - adjust or repair as needed.
Governor and injection pump for leaks and proper operation.
Turbo charger for proper clearance and free movement - as required.
Fuel tank for contaminants and condensation.
Fuel hoses, piping and connections for chafing and restrictions.
Line trap - drain as needed.
Hangers, anchors and supports for exhaust system.
Exhaust for cracks and leaks.
Battery charging system including alternator and external charger, if applicable (optional).
Battery terminals – clean and apply anti-corrosion protectant as needed.
Cable ends, wire connectors and terminals - tighten and repair as needed.
Generator end for signs of heat discoloration.
Panel controls and breakers for signs of heat discoloration and that they are securely mounted.
All gauges for proper operation - during test run.
Frequency and voltage - adjust as necessary.
Complete start up and shut down sequence.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
7
COMPONENT IDENTIFICATION
Components of the generator are expressed in either mechanical or electrical terms. Although distinctly
separate, these two sets of terminology are frequently used interchangeably. To clarify confusion among
conversation – below is the correct terminology:
MECHANICAL:
Rotor: The rotating part of the generator.
Stator: The stationary part of the generator.
ELECTRICAL:
Exciter Field: Produces a magnetic field that induces AC output from the exciter armature
Exciter Armature: Powers main field via rotating rectifier.
Main Field: Produces a magnetic field that induces AC output from main armature.
Main Armature: AC output to receptacles and terminals.
GENERATOR ASSEMBLY (Gen-Set)
In the operation and parts manual this component is identified as the Generator Assembly (Gen-Set).
It consists of the following:
Main Field
Exciter Armature
Rotating Rectifier
Converts AC to DC.
Surge Protector
Is connected in parallel with the field coil and
protects the rotating rectifier from excessive voltage
surges produced in the field coil.
Stator Frame
Housing which encloses the main armature and
exciter field.
Main Armature
Exciter Field
Supplies a magnetic field to the exciter armature
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Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
COMPONENT IDENTIFICATION
Automatic Voltage Regulator (AVR)
The Automatic Voltage Regulator (AVR) maintains a
constant voltage level during load changes.
AVR internal sensors regulate the configuration of
the Open-Delta connections and automatically
adjust the amount of DC current directed to the
exciter field in order to maintain stable output
voltage.
Rheostat (Voltage Regulator)
Is variable resistor connected directly to the AVR
and is used for fine tuning output voltage.
NOTE: In the operation and parts manual this component
is identified as the Rheostat (when ordering parts). In the
wire diagrams it is identified as the Voltage Regulator
(VR).
Voltage Selector Switch (SW)
Is used to configure the generator coils for selected
voltage output by re-configuring the internal contacts
each time a voltage selection is made.
NOTE: Voltage Selector Switch (SW) is not used on
generators above DCA 150.
Control Panel
There are switches located on the
control panel that should not be
confused with the voltage selector
switch. These switches are used to
select lines to be monitored via
gauges and are for monitoring
purpose only.
Gauges:
Indicates output frequency in hertz
Indicates current drawn from load
Indicates output voltage
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
9
COMPONENT IDENTIFICATION
Over Current Relay (Thermal Overload Relay)
In the operation and parts manual this component is
identified as the Over Current Relay (OCR). It is
connected to the main circuit breaker and it monitors
current to the output terminals via the current
transformers, in the event of an overload or short
circuit it will electronically trip the main circuit
breaker.
Main Circuit Breaker (CB1)
The Main Circuit Breaker (CB1) protects the
generator output terminals U V W from overload.
Current Transformer (CT)
The Current Transformers (CT1, 2, 3) sense output
current supplied by the Gen-Set and are connected
to the ammeter and the OCR.
Relay Unit (RY1)
This relay disconnects the V-leg at the AVR and AC
volt-meter when generator is operated in the 120/240
single phase setting.
Twist Lock Receptacles
120/240V 50 amp twist lock receptacles, these can
only be used when the selector switch is placed in
the single phase 120/240 position and the main
circuit breaker closed, (CS-6369).
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Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
GENERATOR SPECIFICATIONS
MODEL
DCA25SSI
DCA45SSI
DCA70SSI
DCA85SSJ
DCA125SSI
DCA150SSI
DCA150SSJ
Engine Model
Isuzu
BV-4LE2
Isuzu
BU-4JJ1T
Isuzu
BJ-4JJ1X
John Deere
4045HF285
Isuzu
BJ-4HK1X
Isuzu
6HK1X
John Deere
6068HF285
Horse Power
34.3
67.1
97.9
126
173
240.1
197
Displacement
2179 cc
2999 cc
2999 cc
4500 cc
5193 cc
6800 cc
6800 cc
Engine (RPM)
No. of Cylinders
1800 RPM
4
4
4
4
4
4
4
17 gal.
26 gal.
40 gal.
40 gal.
63 gal.
74 gal.
69 gal.
Fuel Consumption
•••••••
•••••••
•••••••
•••••••
•••••••
•••••••
•••••••
full
3/4
1/2
1/4
1.66
1.21
0.85
0.58
Fuel Capacity
load • gph
load • gph
load • gph
load • gph
gal
gal
gal
gal
2.8
2.1
1.5
0.9
gal
gal
gal
gal
4.1
3.1
2.2
1.4
gal
gal
gal
gal
5.3
4.4
3.3
2.0
gal
gal
gal
gal
7.3
5.7
4.1
2.5
gal
gal
gal
gal
8.9
7.5
5.0
3.1
gal
gal
gal
gal
9.0
7.1
5.2
3.0
gal
gal
gal
gal
Coolant Capacity
1.74 gal.
2.96 gal.
3.09 gal.
3.91 gal.
5.33 gal.
7.1 gal.
4.6 gal.
Eng. Oil Capacity
2.25 gal.
3.83 gal.
3.96 gal.
3.88 gal.
6.1 gal.
10.6 gal.
8.19 gal.
Eng. Oil Type
Emissions
CHEVRON • Delo 400 LE • 15W40
Interim Tier 4
Interim Tier 4
Tier 3
Tier 3
Tier 3
Tier 3
Tier 3
63 dB
65 dB
68 dB
68 dB
68 dB
69 dB
68 dB
1541 lbs
2464 lbs
3035 lbs
4107 lbs
5182 lbs
6417 lbs
5198 lbs
MODEL
DCA25USI
DCA45USI
DCA70USI
DCA85USJ
DCA125USI
••••••••
DCA150USJ
Engine Model
Isuzu
BV-4LE2
Isuzu
BU-4JJ1T
Isuzu
BJ-4JJ1X
John Deere
4045HF285
Isuzu
BJ-4HK1X
•••••••••
John Deere
6068HF285
Horse Power
34.3
67.1
97.9
126
173
•••••••••
197
Displacement
2179 cc
2999 cc
2999 cc
4500 cc
5193 cc
•••••••••
6800 cc
Sound Level • dB
Full load at 23 feet
Wet Weight • lbs
Engine (RPM)
No. of Cylinders
1800 RPM
4
4
4
4
4
•••••••••
4
Fuel Capacity
41.7 gal
79.2 gal
103 gal
126 gal
169 gal.
•••••••••
214 gal
Fuel Consumption
•••••••
•••••••
•••••••
•••••••
•••••••
full
3/4
1/2
1/4
1.64
1.2
0.86
0.57
gal
gal
gal
gal
2.7 gal
2.1 gal
1.5 gal
0.95 gal
4.1
3.1
2.1
1.3
Coolant Capacity
1.7 gal.
3.15 gal.
3.57 gal.
4.76 gal.
5.2 gal.
•••••••••
5.8 gal.
Eng. Oil Capacity
2.25 gal.
3.83 gal.
3.96 gal.
3.88 gal.
6.1 gal.
•••••••••
8.19 gal.
load • gph
load • gph
load • gph
load • gph
gal
gal
gal
gal
Eng. Oil Type
Emissions
Sound Level • dB
Full load at 23 feet
Wet Weight • lbs
5.3
4.3
3.1
2.0
gal
gal
gal
gal
7.3
5.7
4.0
2.1
gal
gal
gal
gal
•••••••
8.6
6.9
5.2
2.9
•••••••••
gal
gal
gal
gal
CHEVRON • Delo 400 LE • 15W40
Interim Tier 4
Interim Tier 4
Tier 3
Tier 3
Tier 3
•••••••••
Tier 3
59 dB
58 dB
60 dB
63 dB
65 dB
•••••••••
63 dB
2132 lbs
3499 lbs
4553 lbs
6048 lbs
7012 lbs
•••••••••
8223 lbs
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
11
TROUBLESHOOTING
The following troubleshooting chart
was made from common calls received
in the Technical Support department. If
you don’t see your situation below,
contact one of our Technical Support
coordinators at (800) 421-1244
SYMPTOM
No Voltage Output
POSSIBLE PROBLEM
AVR ○ (fuse, defective)
AC Voltmeter ○ (check output w/ multi-meter)
Breaker ○ (tripped, defective)
Exciter Field ○
Loose Wiring ○ (check and repair)
Rotating Rectifier ○ (defective)
OCR ○ (tripped)
REFERENCE PAGE NO #
AVR ……………………………...... page. 16
Breaker …………………………… page. 22
Exciter Field …… ……………… page. 14
Rotating Rectifier …………………. page. 15
OCR .………………………….. …... page. 23
Low Voltage Output
AVR ○ (coarse adjustment)
Engine Speed ○ (1800 RPM)
Rheostat ○ (fine adjustment)
Surge Protector ○ (defective)
Main Field Coil ○ (check and repair)
High Voltage Output
AVR ○ (defective)
Engine Speed ○ (1800 RPM)
Loose Wiring ○ (check and repair)
Output Voltage Hunting
AVR ○
Engine Speed ○ (1800 RPM)
EGC ○ (adjustment)
EGC .………………………………... page. 39
Output Voltage is not
Adjustable
Rheostat ○
Rheostat
Voltage is Higher on One
Output Leg
Voltage Selector Switch ○
Voltage Selector Switch…………… page. 18
Voltage Selector Switch
Hard or Impossible to Turn
Voltage Selector Switch ○ (Replace it)
Voltage Selector Switch…………… page. 18
Amperage Output with no
Load Attached
Voltage Selector Switch ○
Main Armature ○
Voltage Selector Switch…………… page. 18
Main Armature ………………...…… page. 14
Breaker ……………………………… page. 22
Main Circuit Breaker Trips
Breaker ○
Load ○ (over current)
OCR ○
Short Circuit ○ (check and repair)
AVR ……………………………...…. page. 16
Rheostat ………………………. …. page. 21
Surge Protector ……………..……. page. 15
Gen-Set Data … ……………..……. page. 17
AVR …………………………………. page. 16
AVR …………………………………. page. 16
………….. …………….. page. 21
OCR …………………………………. page. 23
PREVENTION
Proper equipment maintenance will prevent the occurrence of most problems. As in all troubleshooting situations, when a
problem does occur, an understanding of the problem and a logical process of elimination are required to identify the root
cause.
12
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
FREQUENTLY ASKED QUESTIONS
Below is a list of common questions
received in the technical support
service department
Why are the twist-lock 50 amp receptacles not working (not putting out power - voltage) ……..?
The twist-lock 50 amp receptacles only work when the generator is set in the 1ø position
they DO NOT work when the generator is set in the 3ø positions (this is normal operation).
The main circuit breaker will not reset (why) …….?
The Over Current Relay (OCR) has been tripped and needs to be reset before the main
breaker can be reset. The OCR trips when maximum amperage capacity has been
exceeded.
The temperature alert indicator lamp is on, and the engine temperature is normal (is this bad) …..?
If your generator has a cold weather kit installed, you will notice the ALERT LED comes on.
This is not an alarm indicator. The ALERT LED is an indicator for fan operation, it will
illuminate when fan turns on; fan turns on @ 180° F ahrenheit (this is normal operation).
Does the generator end bearing require servicing …….?
All current model generators have a NO maintenance required bearing. Older models had
grease packing required as part of maintenance.
I replaced the engine temp sensor but the engine still shuts down with hi temp indicator on (why)…?
The engines have two types of triggers one is for gauges (sensor) and one is for engine shut
down (switch). When replacing ensure you are replacing the correct part.
SENSORS: have a resistance reading depending on temperature.
SWITCHES: either open or close to ground depending on temperature.
This rule also applies to the oil pressure sensor and switch.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
13
GEN SET
Main Armature:
Wires
Qty
Load leads
-
Identification
14 -
(color) Black … U1, U2, U3, V1, V2, V3, W1, W2, X1, X2, Y1, Y2, Z1, Z2
These wires are AC outputs and they are connected to the selector switch.
Wires
Qty
Open delta leads
4
Identification
-
(color) Black ……..… A, B, C, D
These wires supply the supplementary voltage needed to maintain a steady state excitation output during
the different level of loads. Wires are connected to the AVR through connector CN-1
Exciter Field:
Wires
Qty
Excitation leads
2 -
Identification
(color) Black ………..… J, K
These excitation leads are connected to the AVR on the same connector as the open delta leads CN-1
Main Field:
Wires
Qty
Leads
2
Identification
(color) Black leads ……..No Markings
These leads are connected to DC positive & DC negative terminals on the
Rotating Rectifier in conjunction with Surge Protector
Exciter Armature:
Wires
Qty
Leads
3
Identification
(color) Yellow leads…… No Markings
These leads are connected to the U, V, W terminals on the Rotating Rectifier.
IMPORTANT: Inspect the components above with multi-meter set on Ohms Ω – measure resistance across the leads, and
compare reading to the resistance chart on page 17 if reading indicates an open circuit, component may need to be
replaced or sent in to get rewound. This DOES NOT apply to the Surge Protector.
14
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
ROTATING RECTIFIER / SURGE PROTECTOR
Rotating Rectifier:
Connected to both the (main field) & (exciter armature) and is mounted on the exciter armature
To properly check rectifier for continuity you must disconnect (un-solder) all leads.
Set multi-meter for diode testing
Place the positive lead from multi-meter on the DC Positive (+) terminal of the rectifier. Now touch the U, V and W
terminals one at a time with the negative (-) lead, each contact should give a continuity reading.
Reverse - negative multi-meter lead on the DC Positive (+) terminal and touch U, V and W with positive lead. This
should cause the multi-meter to read Infinity.
If the rectifier does not meet the above specifications – replace it.
Surge Protector:
Mounted - (soldered) directly on the Rotating Rectifier in conjunction with the Main Field black leads.
NOTE: Isolate to test, disconnect, (un-solder) all leads. With multi-meter touching the leads, this should indicate an
open circuit, if continuity or other reading is obtained – replace it.
U
V
W
DC
Positive
DC
Negative
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
15
AUTOMATIC VOLTAGE REGULATOR
There are four connectors that attach to the AVR and two wires to the AVR terminals. The AVR also has three
potentiometers, only one is for course adjustment the other two should NOT be touched.
IMORTANT: There is no procedure for directly testing the AVR, use process of elimination.
8 amp fuse MQ part # 6978K753
Open delta leads and excitation leads connect to
the AVR on this connector.
DCA 25 ONLY
A ~ Wire is – YELLOW
B ~ Wire is – ORANGE
C ~ Wire is – WHITE
D ~ Wire is – GRAY
J ~ Wire is – RED
K ~ Wire is – BLUE
DCA 45 to DCA 150
A ~ Wire is labeled ~ A
B ~ Wire is labeled ~ B
C ~ Wire is labeled ~ C
D ~ Wire is labeled ~ D
J ~ Wire is labeled ~ J
K ~ Wire is labeled ~ K
(wires colors are black)
This connector has no outside connection and has a
couple of bridge jumper wires.
P1, P2 ~ Wire is WHITE and are bridged together.
ℓ, K ~ Wire is WHITE and are bridged together.
Wires connected here are for AVR internal sensing.
Two WHITE wires from the V-Leg
Relay are connected here.
U ~ Wire is RED and is connected to terminal # 14 on the voltage selector switch.
V ~ Wire is WHITE and is connected to V-Leg Relay (RY1)
W ~ Wire is BLUE and is connected to terminal # 36 on the voltage selector switch.
This potentiometer (pot) is the
voltage course adjustment pot.
This connects the Rheostat (VR) to the AVR.
1 ~ Wire is GRAY
3 ~ Wire is YELLOW
VISUAL REMINDER: The pots
are positioned similar to a
backwards capital letter ‘L’
DO NOT! adjust the other two pots, these are factory pre-set.
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Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
GEN-SET DATA
The chart below can be used as a reference guide for measuring resistance on the Gen-Set
RESISTANCE MEASURED IN OHMS Ω
CROSS REFERENCE CHART
Main Armature
Generator
Gen-Set
Model #
Model #
DCA-25SSAI
AVR Inputs
Main
Exciter
A-B
Armature
Field
Armature
Field
AC Outputs
DC+ DC-
UVW
J+ K-
0.14
2
0.47
51
51
-
Field 2
B-C
C-D
D-A
0.9
2.7
DCA-25SSI
DB-0281
0.155
1.09
0.16
14
-
0.83
2.5
DCA-25SSI2
DF-0270
0.124
4
0.3
17.6
-
0.9
2.7
DCA-25SSIU / SSIU2
DF-0270
0.124
4
0.3
17.6
-
0.9
2.7
DCA-25USI / USI2
DF-0270
0.124
4
0.3
17.6
-
0.9
2.7
0.1074
0.143
0.143
13
13
0.5
1.5
DCA-40SSAI
-
DCA-40SSI
DB-0501
0.082
1.46
0.21
15
-
0.74
2.22
DCA-45SSIU
DB-0501
0.082
1.46
0.21
15
-
0.74
2.22
DCA-45SSIU2 / SSJU3
DB-0501
0.082
1.46
0.21
15
-
0.74
2.22
DCA-45SSIU4
DH-0480
0.099
1.33
0.137
18.8
0.78
2.15
DCA-45USI
DB-0501
0.082
1.46
0.21
15
DCA-45USI2
DH-0480
0.099
1.33
0.137
18.8
0.042
0.93
0.143
12
12
0.41
1.25
0.048
1.8
0.21
15
-
0.61
1.83
DCA-60SSAI
DCA-60SSI / SSI2
DB-0661
-
0.74
2.22
0.78
2.15
DCA-70SSJU / SSJU2
DB-0831
0.032
1.2
0.08
17.3
-
0.37
1.11
DCA-70SSI / SSIU
DB-0831
0.032
1.2
0.08
17.3
-
0.37
1.11
DCA-70SSIU2
DH-0750
0.046
1.79
0.137
18.8
-
0.67
1.85
DCA-70USJ / USI
DB-0831
0.032
1.2
0.08
17.3
-
0.37
1.11
DCA-70USI2
DH-0750
0.046
1.79
0.137
18.8
-
0.67
1.85
DCA-85SSJU / SSJU2
DB-1001
0.021
1.33
0.08
17.3
-
0.32
0.96
DCA-85USJ /USJ2
DB-1001
0.021
1.33
0.08
17.3
-
0.32
0.96
DCA-85SSK / SSM
DB-1001
0.021
1.33
0.08
17.3
-
0.32
0.96
DCA-100SSJU
DB-1101
0.022
1.4
0.08
17.3
-
0.32
0.97
DCA-125SSK
DB-1381
0.015
1.52
0.08
17.3
-
0.28
0.84
DCA-125SSM / SSM2
DB-1381
0.015
1.52
0.08
17.3
-
0.28
0.84
DCA-125SSJU
DB-1381
0.015
1.52
0.08
17.3
-
0.28
0.84
DCA-125USJ / USI
DB-1381
0.015
1.52
0.08
17.3
-
0.28
0.84
DCA-150SSK / SSK2
DB-1651
0.011
1.75
0.08
17.3
-
0.27
0.82
DCA-150SSM
DB-1651
0.011
1.75
0.08
17.3
-
0.27
0.82
DCA-150SSJU / SSV
DB-1651
0.011
1.75
0.08
17.3
-
0.27
0.82
DCA-150SSJU2
DB-1651
0.011
1.75
0.08
17.3
-
0.27
0.82
DCA-150USJ / USJ2
DB-1651
0.011
1.75
0.08
17.3
-
0.27
0.82
Name of Part
Wires
Location of Wires
Measuring between AC Output leads
Exciter Field
J&K
(connected to AVR)
Exciter Armature
UVW
(connected to rotating rectifier)
Main Field
DC+ DC –
(connected to rotating rectifier)
Main Armature
12 Load Leads
4 Open Delta Leads
(AC Outputs)
(connected to AVR – A,B,C,D)
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
U1 to X1
U2 to X2
V1 to Y1
V2 to Y2
W1 to Z1
W2 to Z2
17
VOLTAGE SELECTOR SWITCH
When inspecting the selector switch visually look for burned spots, discoloration, smoke damage,
damaged cables and connectors. Also rotate the switch (with unit not running) and ensure there is
proper rotation with no sticking between positions or a locked switch without the ability to turn. If any of
these faults are found • replace the switch.
BENCH TEST
Remove and disconnect all cables EXCEPT (wire jumpers & metal jumpers), DO NOT remove jumpers
during testing. Test the switch using the above contact diagrams. Switch must be tested in all three (3)
positions. If any contacts test the opposite of diagram • replace the switch and rewire according to the
specified generator wire diagram.
REPLACEMENT SWITCH
On some models the voltage selector switch has been discontinued and replaced with a new style
voltage selector switch. The new style will look different and comes with new installation brackets that
replace the old brackets.
When receiving a new style replacement switch it is required to position the jumpers in the same
terminal designation as old switch. Also, the wire connectors are different therefore customers will
have to cut the terminal wire connector ends from the wirings and change them to a new style that they
will need in order to fit the new switch.
NOTE: MQ does not supply new wire connectors since this is something that most service shops have
on hand.
Replacement Brackets
Discontinued Brackets
Discontinued Switch
New Style
Replacement Switch
18
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
VOLTAGE SELECTOR SWITCH
The internal connections between terminals on the voltage selector switch are indicated by an
used are external *metal and **wire jumper connectors, see page 20 for jumper locations.
2
4
6
2
POSITION
4
6
1
2
1
2
3
4
6
3
4
5
6
5
8
7
9
12
11
13
15
Position 2: = 3 ø 480 / 277
–
7
8
9
10
–
Position 4: = 3 ø 240 / 139
11
14
13
16
15
Position 6: = 1 ø 240 / 120
–
12
14
16
–
17
–
18
17
–
18
19
–
20
19
–
20
22
21
24
23
25
26
25
26
27
28
27
28
30
29
30
32
31
34
33
36
35
38
37
40
39
40
42
41
42
44
43
–
44
45
–
46
21
23
–
29
31
33
–
35
–
37
39
41
43
–
22
24
–
32
34
–
36
–
47
o
o
o
o
o
o
10
DCA-25SSI
DCA-45SSI
DCA-60SSI
DCA-70SSI
DCA-70SSJ
DCA-100SSJ
o
o
o
o
o
o
DCA-100SSV
DCA-125SSI
DCA-125SSJ
DCA-150SSI
DCA-150SSJ
DCA-150SSV
38
48
o
o
o
o
o
o
DCA-25USI
DCA-45USI
DCA-70USI
DCA-85USI
DCA-125USJ
DCA-150USJ
See page 20 for external jumper locations
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
19
also
VOLTAGE SELECTOR SWITCH
* Metal Jumper Connections
o
o
o
o
DCA-25SSI
DCA-45SSI
DCA-70SSI
DCA-100SSV
o
o
DCA-150SSV
DCA-150USJ
o
o
DCA-25USI
DCA-45USI
o
o
DCA-70USI
DCA-85USJ
** Wire Jumper Connections
o
o
o
DCA-25SSI
DCA-45SSI
DCA-70SSI
o
DCA-100SSV
o
o
DCA-25USI
DCA-45USI
20
DCA-150USJ
o
o
DCA-150SSV
o
o
o
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
DCA-70USI
DCA-85USJ
DCA-125USJ
OPEN DELTA / RHEOSTAT DATA
For best results when measuring, use accurate tools that are properly calibrated.
OPEN DELTA
The Open Delta contacts can be used for troubleshooting. Disconnect the CN1 connector on the AVR and
you can measure the resistance of the Open Delta windings at the connector.
Connector
Measuring Between Wires
Value
CN1………………………………………A & B……………..…………….(50 – 90 AC voltage)
CN1………………………………………A & D……………………………(50 – 90 AC voltage)
CN1………………………………………C & D……………………………(50 – 90 AC voltage)
CN1………………………………………B & C………………………………….(10 AC voltage)
LOCATION: CN1 connector is on AVR
RHEOSTAT
Symptom: AC voltage output is half the normal value and there is no response
when adjusting rheostat.
Disconnect the CN4 connector on the AVR and you can measure the resistance
of the rheostat at the connector.
The multi-meter should indicate a smooth change in resistance value while
rotating the adjustment knob back and forth between min & max.
Connector
Measuring Between Wires
Value
CN4……………………………1 & 3……………………. (0 – 1000 Ohms Ω)
If the Rheostat indicates open or varies from the above - it should be replaced
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
21
MAIN CIRCUIT BREAKER / AMP RATING CHART
This Main Circuit Breaker (CB) connects and disconnects the generator to the output terminal lugs (U, V, W)
and is monitored by the OCR.
99% of the breaker trip faults are due to insufficient sizing of the generator to the load. It is essential that the
unit being used for the application be sized properly to the load in order to prevent these types of nuisance
faults.
IMORTANT: Verify load and ensure it is not causing the breaker to trip.
Proper sizing formulas can be found in operation and parts manuals.
Checking continuity between contacts while tripping the CB will verify operation.
o
o
OFF position reading between input and output contacts should be OPEN
ON position reading between input and output contacts should be CLOSED
Amps @
Amps @
Amps @
Amps @
MODEL
240VAC
3 Ø
480VAC
3 Ø
120VAC
1 Ø
240VAC
1 Ø
DCA • 25
60 Amps
30 Amps
55.6 Amps
DCA • 45
108 Amps
54 Amps
DCA • 70
168 Amps
DCA • 85
Circuit Breaker
Trip Rating
Over Current
Relay Trip
Set Point
27.8 Amps
60 Amps
30 Amps
100 Amps
50 Amps
110 Amps
54 Amps
84 Amps
155.5 Amps
78.8 Amps
175 Amps
84 Amps
204 Amps
102 Amps
188.9 Amps
94.9 Amps
250 Amps
102 Amps
DCA • 100
241 Amps
120 Amps
222.2 Amps
111.1 Amps
250 Amps
120 Amps
DCA • 125
300 Amps
150 Amps
277.8 Amps
138.9 Amps
300 Amps
150 Amps
DCA • 150
361 Amps
180 Amps
333.3 Amps
166.7 Amps
400 Amps
180 Amps
22
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
OVER CURRENT RELAY
The Over Current Relay (OCR) is used on MQ generators and is mounted (snaps onto) a base. The base
is mounted to the machine.
In the event of an overload, both the circuit breaker and the OCR may trip. If the circuit breaker can not be
reset, the reset button on the OCR must be pressed. The OCR is located behind the main control panel.
RESETTING
The reset button is located on top of the OCR and is
blue in color. To reset press the button, it does not stay
down when pressed it is spring loaded and will return to
the up position.
TESTING
1. Press the reset button
2. SLIDE the manual trip lever, this trips the OCR
3. When tripped the contacts 95-96 opens, the
contacts 97-98 closes.
4. Checking continuity between contacts while
tripping the OCR will verify operation.
NOTE: Activating the test button while the unit is
running will shunt trip the main circuit breaker.
Only perform with no load on the generator.
Trip Lever
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
23
OVER CURRENT RELAY
FACTORY SETTINGS
Test Trip Lever
Manual / Automatic reset – this is pre-set at
factory to Manual and should not be
changed.
SAFETY NOTE: This dial must remain in
the Man position, if placed in the Auto
position relay will automatically reset after a
release (trip) and could cause damages to
persons or property.
IMPORTANT: AMP range is preset at factory per generator model.
DO NOT ADJUST. If changed main
breaker may not trip.
RO = Reset and Turn Off
R = Only Reset
AMP setting range
The reset button dial is
pre-set to RO
If replacing, be sure to set to
factory settings of original OCR
96, 97 Signaling contacts are
connected to Circuit Breaker
Connected to the Ammeter & Ammeter Switch
1, 3, 5 Sensing contacts
are connected to
Current Transformers
24
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
Mounting Base
EDUCATION
The following information provided is for educational purpose. For more in depth training on Multiquip
generators, University of Multiquip (UMQ) offers comprehensive training for salespeople or service
technicians covering a complete range.
Contact your local MQ rep or visit the Multiquip website at www.multiquip.com search under service and
you will find more information about UMQ.
INDEX
EDUCATION
Current Flow Diagram ……………………………………….…………………………………….…..26
Generator Theory ……………………………………………….………………………………….…..27
Heat Rise ……………………………………….………………….…………………………………....28
Insulation Class .………………………………………………………….……………………………..29
Meg-Ohm-Meter ……………………………………………………………….………………………..30
Open Delta ………………………………………………………………………………………………31
GFCI ……………………………………………………………………………………………………...32
Circuit Breaker / Short Circuit / Surge Protector …………………………………………………….33
Load Banking ……………………………………………………………………………………………34
Motor Starting Curve …………………………………………………………………………………...35
ENGINE CONTROLS
Index ……………………………………………………………………………………………………..36
WIRING SCHEMATICS
Index …………………………………………………………………………………………………….49
GENERATOR GLOSSARY
Index …………………………………………………………………………………………………….78
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
25
CURRENT FLOW DIAGRAM
NOTE: Current flow diagram represents the basic flow in the generator. Some
components may not be shown example:
Voltmeter, voltmeter - switch, frequency - meter, rectifiers, relays, wire - terminals,
connectors, etc.
26
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
GENERATOR THEORY
The generator creates electricity by a series of fine wire windings inside a magnetic field, called an
armature. As the armature is spun inside this magnetic field by the diesel engine, current and voltage
gets generated in those windings of wire and electricity is transferred. That current and voltage will be
directly proportional to the speed that the armature spins and to the strength of the magnetic field.
Each complete revolution, one complete cycle of alternating current (AC) is developed. This is called a
rotating armature.
Most current generator designs, including MQ, utilize a rotating field type generator. The magnetic field
rotates inside the main armature.
The frequency of the generated voltage is dependent on the number of field poles and the speed at
which the generator is operated. Frequency, measured in Hertz (Hz), is the number of complete cycles
per second in alternating current direction. As current flows through the armature, there is some
amount of resistance and inductive reactance. The combination of these make up what is known as:
the Internal Resistance. When the load current flows, a voltage drop is developed. When a Direct
Current (DC) voltage is applied to the field windings of a DC generator, current flows through the
windings and sets up a steady magnetic field. This is called Field Excitation.
An exciter is part of the generator package supplying direct current to the alternator field windings to
magnetize the rotating poles. The exciter output may be controlled by a voltage regulator. Types of
exciters include brush type with rotating commutator, static excitation or brush less generator and
exciter. A regulator is an important option to consider if there is frequency or voltage sensitive
equipment such as computers.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
27
HEAT RISE
What is heat rise?
Generator ends are rated by “Heat Rise” at a given ambient temperature and load. When current is
put through a conductor the amps cause resistance and the result is heat, the temperature increase
due to resistance is the “Heat Rise”. Normally, all generators are rated in degrees Celsius and at an
ambient temperature of 40 degrees Celsius (104 degrees Fahrenheit).
All DCA series generator ends are rated at an 85 degrees ºC “Heat Rise” at the Prime rating and
105 degrees at the standby rating. This is really robust! The next time you hear someone talk about
an oversized generator end “THAT’S MQ”. Our competitors rate their generators at a much higher
“Heat Rise”. For example Wacker and Magnum is anywhere from 105 ºC to 125 ºC. Baldor is rated
at 125 ºC. and Generac rates theirs up to 150 ºC. This is very hot and the generators will experience
reduced life.
This difference may not seem like much but remember we are using degrees Celsius not
Fahrenheit. When you compare temperatures in degrees Fahrenheit the differences are great. An
MQ generator end rated 85 degrees ºC equates to 185 degrees ºF. A Baldor rated at 125 degrees
ºC is 257 degrees ºF. That’s a difference of 72 degrees ºF. Remember that “Heat Rise” goes above
and beyond ambient temperature. If this unit runs at 40 degree ºC / 104 degree ºF then the “Heat
Rise” is added to the total temperature of the generator windings, increasing the total winding
temperature.
The “Heat Rise” of a generator end directly relates to the amount of copper in it. An alternator with
less copper means higher temperature. Reduced copper means less cost. This is an area where our
competitors can cut cost and sell for less. The fact is MQ uses more copper in our patented
generator ends coupled with a patented excitation system results in greater motor starting
capabilities, increased longevity and a great reputation.
Many times competitors state that they have Class H insulation and MQ uses Class F. The class of
the insulation used directly relates to the temperature that the insulation can withstand and does not
relate in any way to the quality or thickness of the insulation. Class F is rated up to a 135 degrees
“Heat Rise” and Class H is rated to a 155 degrees “Heat Rise”. Other companies uses class H
because they have too; their generators have less copper and operate at much higher temperatures
than then the DCA series generator.
Understanding “Heat Rise” and “Insulation Class” really helps in comprehending the value of an MQ
generator.
For more on Insulation Class see next page
28
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
INSULATION CLASS
What is Insulation Class?
Insulation systems are rated by standard NEMA (National Electrical Manufacturers Association)
classifications according to maximum allowable operating temperatures:
Maximum Operation
Temperature
Temperature Allowed
Tolerance Class
Allowable
Temperature
Rise
1.15 service
factor motor 1)
o
o
o
o
A
105
221
60
70
B
130
266
80
90
F
155
311
105
115
H
180
356
125
-
C
•
Allowable
Temperature
Rise at full load
1.0 service
factor motor 1)
F
C
C
T(oF) = [T(oC)](9/5) + 32
1) Allowable temperature rises are based upon a reference ambient temperature of 40oC.
Operation temperature is reference temperature + allowable temperature rise + allowance for
"hot spot" winding.
Example Temperature Tolerance Class F:
40 oC + 105 oC + 10 oC
= 155 oC
In general, a motor should not operate with temperatures above the maximum. Each 10 oC rise above
the rating may reduce the motor lifetime by one half.
Temperature Tolerance Class B is the most common insulation class used on most 60 cycle US
motors. Temperature Tolerance Class F is the most common for international and 50 cycle motors.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
29
MEG-OHM-METER
Good Insulation
Every generator winding, motor and extension cord have electric wire that is covered with some form of
insulation. Electrical wire is normally copper and it is a good conductor of the electric current that
powers motors. The wires insulation must be the opposite of a conductor; it should resist the current
and keep it in its path along the conductor.
The purpose of the insulation around a conductor is similar to that of pipe carrying water. Pressure on
water from a pump causes flow along the pipe. If the pipe was to spring a leak you’d waste water and
lose some water pressure. With electricity, voltage is like the pump pressure causing current to move
along the copper wire. As with the flow of water in a pipe, there is resistance to flow of current but it is
much less along the conductor than through its insulation.
It should be noted that no insulation is perfect; meaning has infinite resistance, so some electricity does
flow along the insulation or even through it to ground. The current passing through the insulation may
only be a millionth of an ampere (one microampere) but it is the basis of insulation testing. A higher
voltage tends to cause more current leakage through the insulation. This current leakage would
become a problem if the insulation has deteriorated.
All this leads us to determine “what is good insulation”. Under normal conditions “good” means a
relatively high resistance to current. Or it can also be stated that a good insulation has the ability to
keep a high resistance. A suitable way of measuring resistance can tell us how good the insulation is.
Also if regular insulation measurements are made you can track trends towards its deterioration.
Causes of Bad Insulation
When generators, welders and electric motors are new the insulation should be at its highest level of
resistance. During equipment use, insulation is subject to many effects which can cause it to fail. These
causes can be mechanical damage, vibrations, excessive heat or cold, dirt, oil, corrosive vapors and
even moisture from humidity. During the life of a conductor’s insulation all of these causes are at work
in combination with electrical stresses. If a pin hole or even a crack in the insulation develops,
moisture and foreign matter can penetrate the surfaces of the insulation. This provides for a low
resistance path for leakage current. Once the insulation has begun to deteriorate all elements of
causes tend to combine until excessive current leakage is allowed through the insulation.
At times the drop in insulation resistance can be sudden, such as occurs if the equipment is flooded.
Normally insulation resistance drops gradually and gives plenty of warning if checked as a preventative
maintenance. Periodic checks would allow planned reconditioning prior to operation failure and the
ability to remove from service if the insulation resistance became dangerously low. Equipment with no
checks may not only be dangerous to touch with voltage applied but also be subject to total burn out. A
failed insulator becomes a partial conductor.
30
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
OPEN DELTA
Why is the open delta design efficient?
As copper softens it generates less power. The open delta design runs with the copper wires at 180º F,
while other competitors models run with their copper wires at 220º, and some are even as bad as 300º
degrees.
One outstanding feature of all MQ WhisperWatt™ engine-generator packages is the patented, Denyo
open-delta design alternator. Of all the hardware assembled to form a complete generator package, the
AC alternator is probably the single most important albeit misunderstood component in the assembly.
The MQ Power alternator is built like no other on the market. This is why MQ Power WhisperWatt™
generators offer industry leading motor starting with minimum voltage dips and quicker recoveries.
The AC alternator or power generator is the device bolted to the back of the engine bell housing the
rotates at engine speed to produce AC voltage and current. The alternator system is basically
comprised of four component systems that work together to produce AC power. These components
consist of the fixed mount stator or armature coils, the rotating field or rotor, the exciter and the
automatic voltage regulator (AVR). What makes MQ better?
MQ's Open Delta Coil Excitation System is design is a separately excited generator. That is, the AC
voltage regulator is powered by a separate excitation winding which is placed on the stator core together
with the armature windings. The excitation winding provides dedicated input power to the automatic
voltage regulator, which controls the AC voltage output. The voltage regulator increases or decreases
exciter current as it senses changes in output voltage and frequency, based on changes in load, thus
increasing or decreasing the generator field strength. The main benefit of having a separate exciter
winding is the fact that the voltage input power supplied to the voltage regulator is un-affected by the
load induce fluxuations, specifically, non linear loads. And, during motor starting operations, the Denyo
automatic voltage regulator switches the configuration of the internal open-delta connections to provide
virtually unlimited excitation voltage, resulting in superior motor starting ability, better voltage response
and voltage transient conditions. The system is so unique in design and benefits, it carries U.S. patent
#4268778.
Other manufacturers systems consist of a self excited generator. That means the input power supplied
to the regulator is tapped from the generator output. The effectiveness of the voltage regulator in
managing this event is somewhat decreased when the available AC voltage signal provided to the
regulator is derived from the same AC voltage circuit being fed to the load. IF there are load induced
fluxuations, precise voltage regulation is compromised.
Other manufacturers' typically offer to provide their alternator with a PMG or permanent magnet
generator. This is an extra cost, bolt on, alternator modification that does provide the voltage regulator
with separately derived voltage input power. However, it is not as effective as MQ. And, it is extra cost.
The combination of the open-delta excitation system and automatic voltage regulation which contribute
to precisely control the generator output voltage and provide a stable supply of in rush current for motor
starting, makes the MQ WhisperWatt™ engine-generator packages superior to all others in the industry.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
31
GFCI
What is a Ground Fault Circuit Interrupter?
A ground fault circuit interrupter (GFCI) is a small device that compares the amount of current flowing
through the circuit. If there is a difference of more then 5 milliamps (.005 amps) the GFCI opens the
circuit.
What are the limits of a GFCI?
There are several limitations that you should be aware of
1. A GFCI is not a tool tester. The GFCI does not have the sensitivity, detection circuits, nor the
polarity, reversal features needed to perform the function of a tool tester. The GFCI makes an
excellent life protection device, but a very poor tool tester.
2. A GFCI does not prevent shocks. The GFCI is only operated when a ground fault occurs.
Someone using the equipment might receive a shock, but it will be a very short duration (1/30 of
a second). There is a chance that a shock, even of this short duration, might cause someone to
experience a fall or similar injury, but electrocution will normally be prevented.
3. A GFCI does not prevent all electrocutions. The GFCI reacts to electric current flowing from
the power line to ground. It does not react to current flow between power lines. In other words,
the GFCI will react to someone standing in water and comes in contact with one of the power
lines. It will not protect someone who is hold the neutral power line in one hand and hot wire with
the other.
4. A GFCI does not replace fuses or circuit breakers. Fuses and circuit breakers are designed
to protect equipment and power lines by reacting to excessive current flow, normally in the order
of 15 to 20 amps.
5. GFCI’s are designed to protect people by reacting to leakage currents to ground in the order of
.005 amps. Except in the case of GFCI / circuit breaker combinations sold to be installed in
building installations, they are separate devices performing separate functions.
Is the ground wire still needed?
The GFCI will work and perform its function with or without the tool being grounded, but the ground
system is an important safety feature and should always be maintained and retested on a regular basis.
Further, if a ground fault should occur, the leakage current will pass down the ground wire and trip the
GFCI without the operator receiving a shock at all. So YES – please retain the ground system.
How can we be sure the GFCI is working?
There are two methods of testing GFCI’s. All GFCI’s sold in this country are provided with a test and
reset button. During maintenance intervals simply plug a tool in to the GFCI and press the test button.
The tool should turn-off and the reset button should pop-out. Depressing the reset button should restart
the equipment. This is an adequate test for most applications.
To measure the actual trip current of a GFCI requires a GFCI tester. The tester allows you to read the
actual GFCI trip current on a meter, identifying the GFCI’s that do not operate within the required four to
six milliamp range.
One test that should not be performed on GFCI’s is a high load test. The GFCI contains small electronic
parts that are damaged if high voltages are applied to them. DO NOT test any GFCI on a HI-POT,
dialectic, or Doyle type tester.
32
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
CB / SHORT CIRCUIT / SURGE PROTECTOR
A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit
from damage caused by overload or short circuit. Its basic function is to detect a fault condition and, by
interrupting continuity, to immediately discontinue electrical flow. Unlike a fuse, which operates once and
then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume
normal operation.
NOTE: always place the main circuit breaker in the “OFF” position prior to starting the engine.
SHORT CIRCUITS
A short circuit (sometimes abbreviated to short or s/c) in an electrical circuit is one that allows a current
to travel along a different path from the one originally intended. The electrical opposite of a short circuit
is an "open circuit", which is an infinite resistance between two nodes. It is common to misuse "short
circuit" to describe any electrical malfunction, regardless of the actual problem. Damage from short
circuits can be reduced or prevented by employing fuses, circuit breakers, or other overload protection,
which disconnect the power in reaction to excessive current.
SURGE PROTECTORS
A surge protector attempts to regulate the voltage supplied to an electric device by either blocking or by
shorting to ground voltages above a safe threshold.
ZENER DIODE: (older generators) A varistor is an electronic component
with a “diode like” voltage characteristic. Varistors are used to protect
circuits against excessive transient voltages by incorporating them into
the circuit in such a way that, when triggered they shunt the current
created by the high voltage away from the sensitive components. A
varistor is also known as Voltage Dependent Resistor (VDR). A varistors
function is to conduct significantly increased current when voltage is
excessive.
METAL OXIDE VARISTOR: The metal oxide varistor (MOV) contains a
material, typically granular zinc oxide that conducts current (shorts)
when presented with a voltage above its rated voltage. MOVs typically
limit voltages to about 3 to 4 times the normal circuit voltage by diverting
surge current elsewhere. MOVs have finite life expectancy and
"degrade" when exposed to a few large transients, or many more
smaller transients. "Degrading" is the normal failure mode. MOVs that
fail shorted are so small as to violate the MOV’s "Absolute Maximum
Ratings". MOVs usually are thermal fused or otherwise protected to
avoid short circuits and other fire hazards.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
33
LOAD BANKING
The purpose of load banking is to imitate the actual load that a power source (generator) will see during
application. Load banking is a technique used to determine maximum stand by power and system
performance. A load bank serves the power source and uses its energy output to test and protect that
source. This method of power generation is beneficial because a real load is often unpredictable and
random in value, the load applied from a load bank provides a controllable load with controls that allows an
operator to incrementally step and vary the load.
Load banking is a critical requirement to ensure the equipment will perform as expected when pressed into
service. This applies to the name (stand by, emergency power or back up) generator.
It is also recommended as part of maintenance to avoid wet stacking. Wet stacking is common when diesel
engines operate for extended periods of time with little or no load applications. Wet stacking is best
described as unburned fuel that accumulates in the exhaust system. A sign of wet stacking is black
seepage around the exhaust connections or black exhaust from the stack after warm up.
The National Fire Protection Association (NFPA) has established standards for monthly maintenance on
stand-by generators. The current standard can be found on the website and referred as (NFPA 110)² which
states “Generators should be exercised monthly at 30 percent of the nameplate rating or loaded to the
minimum engine exhaust temperature recommended by the manufacture.”
Reference:
The National Fire Protection Association (NFPA) Standard for emergency and standby power systems
www.nfpa.org
Load banks are used after service to confirm reliability:
1.
2.
3.
4.
5.
After scheduled maintenance
After AVR adjustments in shop
After component replacement
Gen end replacements / rewinds
Yearly to confirm fuel and engine cooling systems are performing correctly under full loads
34
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
MOTOR STARTING CURVE
STARTING CURVE (SkVA)
0
100
200
300
400
500
600
700
800
900
1000
0
DCA-150SS
DCA-125SS
DCA-100SS
DCA-70SS
DCA-45SS
DCA-25SS
DCA-85SS
-5
VOLTAGE DIP (%)
-10
-15
-20
-25
-30
-35
-40
-45
MODEL
DCA25SSIU
Old MSKva
.4Pf
58
DCA25SS
DCA45SSIU
DCA150SS
63
8%
20
22
11
99
21%
36
37
17
179
22%
56
61
30
265
36%
66
70
44
231
22%
80
88
39
410
33%
100
110
68
545
32%
120
132
91
273
DCA125SSSS
DCA150SSK
LGR. Hp
Code G
181
DCA100SS
DCA125SSK/J
Lit. Stby
Kw
170
DCA85SS
DCA100SSJU
Lit. Prime
Kw
140
DCA70SS
DCA85SSK/M
% of
Increase
78
DCA45SS
DCA70SSJU
New MSKva
.6Pf
372
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
35
ENGINE CONTROLS
The DCA-25-150 Series generators are powered by four cycle engines and are manufactured by Isuzu and
John Deere.
The following information is to provide the service technician with a base level of knowledge on engine
controls and related components. For more on engine maintenance and repairs, see engine manufacturer’s
service manual.
INDEX
ENGINE CONTROLS
Troubleshooting ……………………………………………………………………….. ………………37
ECU …………………………………………………………………………………………………..38-39
Electronic Governor System …………………………………………………………………………..40
o EGC Inspection ………………………………………………………………………………41
o EGC Calibration ……………………………………………………………………………...42
o Magnetic Pick Up …………………………………………………………………………….43
o Actuator ……………………………………………………………………………………….44
o Fuel Relay …………………………………………………………………………………….45
Crank Relay / Glow Plug Relay ……………………………………………………….. ……………..46
Feed Pump Strainer ……………………………………………………………….. …………………47
Wet Stacking ………………….…………………………………………………………………………48
WIRING SCHEMATICS
Index …………………………………………………………………………………………………….49
GENERATOR GLOSSARY
Index …………………………………………………………………………………………………….78
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Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
TROUBLESHOOTING
For more on engines see engine
manufactures manual or you may
contact one of our Technical Support
coordinators at (800) 421-1244
SYMPTOM
POSSIBLE PROBLEM
INFO PAGE NO #
Engine does not start
No fuel ○
Air in the system ○
Water in the fuel system ○
ECU ○ (defective)
Magnetic pick up ○ (defective, adjustment)
Starter ○ (defective, check and repair)
Battery ○ (defective, check and repair)
Emergency Stop Button ○
Engine revolution is not
smooth
Fuel filter clogged / dirty ○ (clean or change)
Air filter clogged ○ (clean or change)
EGC ○ (adjustment)
Surge Protector ○ (defective)
Fuel Relay ○ (defective)
Loose Wiring ○ (check and repair
ECU ○
Magnetic pick up ○
Fuel Relay …………………..…... page. 45
Engine cranks but does not
start
AVR ○
Engine Speed ○
EGC ○ (out of adjustment)
AVR …………………………..…... page. 16
Engine Hunting
EGC Calibration …………..……
Engine start and shuts
down after a few seconds
ECU ○ (check fault and repair)
Low Oil Pressure ○ (check and repair)
Hi Engine Temp ○ (check and repair)
ECU ……………. ……………....... page. 38
See engine mfr. service manual
See engine mfr. service manual
Excessive black smoke
Wet Stack ○
Wet Stacking ………….. ……….. page. 48
Excessive white smoke
Fuel ○ (air in the fuel system)
See engine mfr. service manual
Engine overheating
Thermostat ○ (defective)
Radiator ○ (clogged)
Water Pump ○ (defective)
Coolant Hose ○ (defective)
Replenish fuel
Bleed system
Inspect and clean fuel system
ECU …………………………….… page. 38
Magnetic pick up ……………….. page. 43
EGC Calibration …………..……
Surge Protector. …………..……
page. 41
page. 15
ECU …………………………….… page. 38
Magnetic pick up ……………….. page. 43
page. 41
See engine mfr. service manual
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
37
ECU
The ECU is an auto start / stop engine controller
When referring to ECU in general it stands for Engine Control Unit, this unit is manufactured by Engineering
Concepts Unlimited ECU
The ECU auto start controller should not be confused with the actual engine manufacturers Engine Control
Module (ECM). The ECM monitors engine operational inputs and directly controls outputs for fuel delivery,
actuators, electronic fuel injector, etc. While the ECM does include safety shutdowns its main purpose is
regulating fuel to meet emission standards. The ECM is preprogrammed with proprietary info by the engine
manufacture.
CONTROL SWITCH FUNCTION
Control Switch
AUTO position: When switch is placed in this position the ECU is connected
to the auto-start contacts of the unit. The auto-start contacts are designed to
connect to an automatic transfer switch (ATS) which will control the automatic
start / stop of the engine through the ECU.
MANUAL position: When switch is placed in this position the engine will start
immediately
OFF/RESET position: When switch is placed in this position the engine will
not start or run, these functions are canceled.
LED DEFINITIONS
LOW OIL PRESSURE: Illuminates when engine oil pressure has fallen below 15 psi (103 kPa). The oil pressure is
detected by the oil pressure switch and will signal ECU to shut down the engine. Do not confuse this switch with the oil
pressure sensor.
HIGH COOLANT TEMPERATURE: Illuminates when engine temperature has exceeded 203ºF (110ºC). The water
temperature is detected by the water temperature switch and will signal ECU to shut down the engine. Do not confuse
this switch with the water temperature unit.
OVERCRANK SHUTDOWN: Illuminates when engine starting has failed after a pre-programmed number of attempts
DCA generators are pre-set at 3 cycles with 10 second duration.
OVERSPEED SHUTDOWN: Illuminates when engine is running at an unsafe speed.
ENGINE RUNNING: Illuminates when engine is running at safe operating speed.
38
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
EC U
Wire terminals are located on the back of the LED panel
BACK
FRONT
Below is an example of the basic wiring for the ECU, some generators may differ depending on model.
Check Points
o
o
o
o
o
o
o
o
o
Control Switch: Battery positive voltage is present constantly on center terminal of switch.
Terminal 13: This is manual power input to the ECU voltage is supplied from the control switch to this terminal.
Terminal 14: This is auto power input to the ECU voltage is supplied from the control switch via remote start contacts.
Terminal 6: This is power output, with control switch in manual position check for DC voltage at this terminal.
Terminal 2: This is ground input. Ensure this terminal has continuity to ground.
Terminal 15: This will have constant battery voltage when unit is running.
Terminal 1: This receives an input signal voltage from the Magnetic Pick Up.
Terminal 4: This is connected to oil pressure switch or engine manufacture engine controller.
Terminal 5: This is connected to water temp switch or engine manufacture engine controller.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
39
ELECTRONIC GOVERNOR SYSTEM
The Electronic Governor System consist of four components
Electronic Governor Controller (EGC)
Magnetic Pick Up (MPU)
Actuator (ACT)
Fuel Relay (FR)
In order for the system to operate properly it is necessary for all the above mentioned components to
operate in conjunction with each other. Should one fail, the entire governing system is affected.
Electronic Governor System Operation
The Electronic Governor System controls the engine governor stroke and stability during starting,
variable load conditions and stopping. The Electronic Governor Controller (EGC) is able to perform
this function by receiving a signal from the Magnetic Pick Up (MPU) located on the outer flywheel bell
housing. This MPU sends an AC voltage signal to the EGC which will vary depending on load conditions
affecting the engine r.p.m. The EGC will compare the MPU input signal to preset set-points and will
react accordingly by sending a variable DC voltage signal to the Actuator (ACT) to keep the engine
within manually preset engine r.p.m. parameters.
The EGC receives DC voltage from the Fuel Relay (FR) which is connected directly to the accessory
circuit of the DC wiring harness, typically controlled by terminal 15 on the ECU auto start controller.
NOTE: EGC is a dual voltage controller and can operate in either a 12 V DC or 24 V DC system.
Units produced prior to Tier 2 EPA standards may also have an “idle” function controlled by the EGC
which allows the operator to warm up the engine at an “idle” speed. Units produced within the Tier 2
limits will not have this function.
An EGC is normally not found in Tier 3 engines as the ECM controller controls this speed and fuel rate
functions.
40
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
EGC INSPECTION
IMORTANT: During inspection, malfunctions may lead to other components and may require
technicians to perform a complete analysis of entire system. Understanding the correct operation of the
electronic governor system is essential when testing, diagnosing and performing adjustments to the
EGC.
TOOLS NEEDED: An accurate AC/DC Multi-Meter.
Typical faults symptoms:
There are three test points for the EGC:
Unit cranks but will not start.
Unit starts but only runs at one speed.
Input Control Voltage (DC)
Output Voltage to ACT (DC)
Input Voltage from MPU (AC)
NOTE: governor controller displayed is for educational purpose only actual controller may vary
depending on generator model.
The following voltages should be present on the EGC while cranking the engine
PINS
1-2
(Input Control Voltage) ------------ from Fuel Relay -------- 12 volt system --------- 8V to 12V DC
1-2
(Input Control Voltage) ------------ from Fuel Relay -------- 24 volt system -------- 21V to 24V DC
4-5
(Output Actuator Voltage) --------- to Actuator ------------------------------------------------------ 4V DC
10 - 11 (Input MPU Voltage) ---------------- from Magnetic Pick Up ------------------------------------ 2.5V AC
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
41
EGC CALIBRATION
The following information is general and not model specific always refer to EGC manufacture
documentation for calibration specifications.
Prior to suspecting the EGC as the fault, service the engine to ensure fuel filter and air cleaner is not the
cause for unstable engine speed or response. As the EGC and governor system ages, it is possible for
the EGC to become out of calibration.
TOOLS NEEDED: A fine tip standard screw driver.
1. Observe that potentiometer settings are adjustable from zero to 100%.
2. Set the small dip switch S1 to the off posostion.
3. Set the small dip switch S2 – This switch selects the point at which actuator coil current level causes
the intergrator limit to to be actuated. This level is nominally 6.3 amperes for OFF position and 7.3
amperes for ON position.
4. INITIAL POTENTIOMETERS SETTINGS:
GAIN ---------------- 20%
I -------------------- 20%
D --------------------- 30%
Droop --------------- Zero
5. Start engine (no load)
6. Adjust ◦ SPEED ◦ pot as necessary to obtain specified r.p.m.
7. Adjust ◦ GAIN ◦ pot clockwise until the engine speed begins to oscillate (hunt). (If engine remains
stable at 100% ◦ GAIN ◦, physically disrupt the actuator linkage by hand). With engine hunting, turn the
◦ GAIN ◦ pot counterclockwise until engine speed becomes stable.
8. Repeat step 7 for the ◦ D ◦ pot setting.
9. Repeat step 7 for the ◦ I ◦ pot setting.
After setting pots, it may be necessary to re-adjust engine speed.
With the engine is operating at proper speed (1800 r.p.m.), turn the EGC off (bring to idle, if equipped).
When the engine speed slows down to approximately half of rated speed, turn the EGC back on,
observe the overshoot. If there is a small hunt at steady state, slightly turn the ◦ I ◦ pot counterclockwise
until stable. In some cases a 2 to 5 Hz overshoot may be acceptable.
42
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
MAGNETIC PICK UP
The Magnetic Pick Up (MPU) is an electro magnetic sensor. When a tooth from the engine flywheel
passes under the tip of the sensor, electrical impulses are induced within the coil and sent to the EGC.
The electrical impulse signal Hertz (Hz) is directly proportional to engine speed. The EGC uses this
signal to determine the amount of DC voltage to be sent to the actuator for fuel regulation during start up
and load requirements.
LOCATION: Mounted in flywheel bell housing of the engine.
TOOLS NEEDED: An accurate AC/DC Multi-Meter.
INSPECTION
•
•
•
•
•
•
•
•
Disconnect the MPU connector (isolating MPU).
Using a multi-meter, test for continuity across the two pins on the connector.
If an infinity reading is obtained, replace the MPU.
If continuity is found, continue to next step.
With MPU still disconnected, set multi-meter to AC and place both leads on the MPU connector.
Crank the engine (engine will not start with MPU disconnected).
With engine cranking multi-meter should read ………………………………………3 to 5 volts AC.
If a low reading is obtained try adjusting MPU.
ADJUSTMENT & INSTALLATION
•
•
•
•
•
Loosen lock nut and remove MPU from housing.
Using a screw driver, rotate the flywheel slightly so that one tooth is centered in the MPU port.
Reinstall MPU until it bottoms out (touching the centered tooth).
Back the MPU out of the port ¼ to ½ of a turn and tighten lock nut.
After adjusting re-test. Should the magnetic pick up fail any of the above checks, replace it.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
43
ACTUATOR
The following information is general and not model specific always refer to Actuator manufacture
documentation for specifications.
The Actuator (ACT) is designed to utilize the principle of variable reluctance. It’s basically a simple,
proportional, electric solenoid having a sliding armature whose magnetic force is proportional to input coil
current. Balance between the force of its return spring and magnetic force, the armature glides on anti
friction bearings, proving a hysteresis free linear movement. Linear motion is converted to an output shaft
rotation by a bell crank.
ROTARY ACTUATOR WITH ROTARY FUEL PUMP
ROTARY ACTUATOR WITH LINEAR FUEL PUMP
44
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
FUEL RELAY
The Fuel Relay (FR) sometimes called “ice cube relay” provides the EGC its control DC voltage. Without the
FR the engine governor system will be completely dead and non-operational. The FR is mounted to a base
with terminals to allow its connections.
Testing the FR is simple and does not require any special tooling with the exception of a multi-meter and
proper battery voltage 12V DC or 24V DC depending on the system being used. The layout of contacts on the
FR is shown below.
View of Relay
(Actual)
Older generators may not have the diode in relay shown in diagram below. 1998 and newer generators have
a diode across the coil to prevent back feed. Symptoms for a possible failed relay are cranking with no start.
INSPECTION
Remove FR from base holder.
Using a multi-meter measure between the contact pins (PIN).
Measurements (ohms Ω resistance) should be as follows – Relay not Energized
o
Continuity between ~ PIN 1 and PIN 5 (closed contacts)
o
Continuity between ~ PIN 2 and PIN 6 (closed contacts)
o
Continuity between ~ PIN 7 and PIN 8 (control coil • 12V -160 Ohms Ω / 24V-60 Ohms Ω)
o
Infinity between ~ PIN 3 and PIN 5
(open contacts)
o
Infinity between ~ PIN 4 and PIN 6
(open contacts)
To measure Relay Energized apply 12V DC + to PIN 8 and Negative to PIN 7
Should the FR test normal, problem may be within the base holder. FR base is not “sealed type” and it is
possible to build corrosion and dirt within. This can cause lack of path or continuity. Try cleaning the base.
With FR removed spray dielectric spray cleaner and blow out with compressed air not to exceed 110 PSI.
Reinstall FR and attempt to start engine, if fails continue to next step.
With FR installed and while attempting to start check for DC voltage at PIN 8 + and PIN 7 -
o
If required DC voltage is NOT present, check for voltage at ECU terminal # 15 and any ground, no voltage
indicates problem at the ECU.
If required DC voltage is present and the FR is known to be good, check for voltage at EGC terminal # 1
and any ground, no voltage indicates FR base is defective and needs to be replaced.
o
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
45
CRANK RELAY / GLOW PLUG RELAY
Used on DCA series with ISUZU engines that are equipped with ECU auto start / auto stop engine controller.
Same style relay is used for both crank and glow plugs. This relay is not sealed and has an open body. Most
commonly used relay in Isuzu equipped units is a Deltrol 30 amp relay.
ENGINE CRANK RELAY
The engine crank relay is connected to the starter motor solenoid and directly to the battery for starting. This
relay is fed off the ECU crank circuit located on ECU pin # 6.
ENGINE GLOW PUG RELAY
The engine glow plug relay is connected to the engine glow plugs and directly to the battery for pre-heating.
This relay is fed off the ECU crank circuit located on ECU pin # 6.
DELTROL 30 AMP RELAY
To Starter Solenoid or Glow Plugs
Coil 12V DC
Coil Ground
Battery Positive
BACK
46
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
FEED PUMP STRAINER
STRAINER
Used on DCA45 and DCA70 series with ISUZU engine 4BG1
STRAINER • MQ Part # 1-13260047-0
WASHER / GASKET • MQ Part # 109630085-0
Symptoms of clogged strainer:
Hard starting.
Engine runs rough.
White smoke coming out the exhaust.
The feed pump strainer is located at the water separator in the banjo bolt as shown in the illustration
below. Inspecting and cleaning strainer is considered part of maintenance. If strainer becomes clogged,
remove from banjo bolt and clean in diesel fuel or replace if cannot be cleaned.
NOTE: When replacing strainer always replace banjo bolt washer gasket.
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
47
WET STACKING
STRAINER
Diesel engines that are operated for extended periods with light or no load applied will typically become “wetstacked“. Unless a diesel engine is operated with a sufficient load it will not reach its optimum running
temperature. When the engine is not running at its optimum temperature unburned fuel can build up in the
exhaust system. This can lead to fouled fuel injectors, engine valves and exhaust systems including turbo
chargers and reduce overall performance.
For a diesel engine to operate at peak efficiency it must be able to provide fuel and air in the proper ratio and
at a high enough engine temperature for the engine to completely burn all of the fuel. Wet-stacking does not
always cause permanent damage and can be alleviated if additional load is applied to relieve the condition.
Usually the first sign of wet stacking is wetness in the exhaust stack that looks like oil, thus the term wet
stacking.
Continued operation under wet stacking conditions can cause diminished engine performance, excessive fuel
consumption, and even severe engine failure because of the following conditions:
Excessive unburned fuel in the exhaust system.
Excessive lubricating oil consumption.
Cylinder wall glazing.
Poor cylinder wall lubrication and ring seating.
Collection of unburned combustion particles on exhaust valves, turbo charger and exhaust manifold.
WHAT IS HAPPENING?
All engines are designed to work within a specified load range at specific temperatures. During combustion,
the piston and liner are subject to extreme temperatures. The cylinder wall, fire rings and oil control rings and
valve train are designed to work under these high temperature conditions. The fuel systems are calibrated to
deliver the amount of fuel required to produce the rated horsepower. The cooling systems are designed to
remove any excess heat created to keep the combustion temperatures at optimum levels.
When the engine is operated with insufficient load, several things begin to happen; the high temperature
created during compression ignites diesel fuel. At idle or light loads, the cooling capacity of engine exceeds the
amount of heat produced creating combustion temperatures that are insufficient to burn all of the fuel. Some of
this unburned fuel is left in the combustion chamber while the rest of it is pushed through the exhaust system.
This mixes with the normal exhaust soot to create an oily mixture. Some of it will turn to sludge and gather on
the valve stems where there is enough heat to dry it out, but not burn it, while the rest of it is pushed into the
exhaust system.
In addition to gathering on the valve stems, the unburned fuel begins to create a glaze on the cylinder wall and
interferes with the seating of the rings to the liner. This glaze provides excess lubrication on the rings and
reduces their ability to keep the combustion above the rings and the oil below the rings. The glaze actually
breaks the seal created when the rings seat to the liner. If the glaze is allowed to remain for too long, loading
the engine will not burn off the glaze and allow the rings to reseal themselves. In severe cases, the glaze can
only be removed by disassembling the engine and re-honing the cylinder or liner.
Correcting a wet stacking condition can be done by applying a constant load to the engine to burn out the
excess fuel and oil and reseat the rings. If the engine can be loaded, it needs run with a sustained load until
the wet stacking condition clears up. Often, this can take up to two hours of run time at minimum output of 80%
rated power. The exhaust temperature should be closely monitored during this time. However, the best way to
determine the load on a specific engine is to check with the engine manufacturer and use their published
temperatures as a guideline.
For info on load banking see page 34
48
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
WIRING SCHEMATICS
Due to the many different options available on the DCA-series generators, optional schematics are not
included in this manual.
For more information on DCA generator schematics contact the Service Technical Support Department.
DCA-25SSI
DCA-25SSI
DCA-25USI
DCA-25USI
DCA-25USI
DCA-45SSI
DCA-45SSI
DCA-45USI
DCA-45USI
DCA-45USI
DCA-70SSI
DCA-70SSI
DCA-70USI
DCA-70USI
DCA-85SSJ
DCA-85SSJ
DCA-85USJ
DCA-85USJ
DCA-125SSI
DCA-125SSI
DCA-125USI
DCA-125USI
DCA-150SSI
DCA-150SSI
DCA-150SSJ
DCA-150SSJ
DCA-150USJ
DCA-150USJ
Generator ……………………………………………………………………………..50
Engine …………………………………………………………………………………51
Generator ……………………………………………………………………………..52
Engine Part 1 ………………………………………………………………………...53
Engine Part 2 ………………….……………………………………………………..54
Generator ………………………………………………………………...…………...55
Engine ………………………………………………...……………………………….56
Generator …………………………………………………………………………..…57
Engine Part 1…………………………………………………………………...…….58
Engine Part 2 ……………………………………………………...…………………59
Generator ………………………………………………………………....…………..60
Engine ……………………………………………………………………………...….61
Generator ……………………………………………………....……………………..62
Engine ……………......……………………………………………………………….63
Generator ………………………………………………………………………....…..64
Engine ................................................................................................................65
Generator …………………………………………………………………...…….…..66
Engine …………………………………………………………………………….……67
Generator …………………………………………………………………………......68
Engine ……………………………………………………………………………....…69
Generator ……………………………………………………………………..…..….70
Engine ……………………………………………………………………….……..…71
Generator ……………………………………………………………………………..72
Engine ………………………………………………………………………..……….73
Generator ……………………………………………………………………........….74
Engine …………………………………………………………………………..........75
Generator ………………………………………………………..…………...……...76
Engine .…………………………………………………………………….…………..77
GENERATOR GLOSSARY
Index …………………………………………………………………………………………………..78
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DCA-25SSI GENERATOR
50
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DCA-25SSI ENGINE
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DCA-25USI GENERATOR
52
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DCA-25USI ENGINE - Part 1
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53
DCA-25USI ENGINE - Part 2
54
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DCA-45SSI GENERATOR
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55
DCA-45SSI ENGINE
56
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DCA-45USI GENERATOR
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57
DCA-45USI ENGINE – Part 1
58
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DCA-45USI ENGINE – Part 2
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59
DCA-70SSI GENERATOR
60
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DCA-70SSI ENGINE
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61
DCA-70USI GENERATOR
62
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DCA-70USI ENGINE
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63
DCA-85SSJ GENERATOR
64
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DCA-85SSJ ENGINE
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65
DCA-85USJ GENERATOR
66
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DCA-85USJ ENGINE
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DCA-125SSI GENERATOR
68
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DCA-125SSI ENGINE
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DCA-125USI GENERATOR
70
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DCA-125USI ENGINE
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71
DCA-150SSI GENERATOR
72
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
DCA-150SSI ENGINE
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73
DCA-150SSJ GENERATOR
74
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DCA-150SSJ ENGINE
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75
DCA-150USJ GENERATOR
76
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DCA-150USJ ENGINE
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GENERATOR GLOSSARY
Ammeter - An instrument that measures electric current in amperes.
Amperage (Amps) - The strength of a electrical current measured in amperes.
Armature - That part of a generator or of an electric motor in which a current is induced by a
magnetic field. The armature usually consists of a series of coils or groups of insulated
conductors surrounding a core of iron. See page 8 for more information.
Automatic Voltage Regulator (AVR) - Increases or decreases exciter current for a more linear
voltage and frequency. See open delta page 30 for more information.
Brushless Design - The purpose of the generator brush is to absorb power from the rotating
armature of a generator and supply it to the stationary part of the generator. These brushes
have a short life due to erosion. Multiquip’s unique brush less design calls for lower
maintenance and a longer generator life. See open delta page 30 for more information.
Circuit Breaker (CB) - Connects and disconnects the generator output from the output
terminals. It also protects the generator from short circuits or overloads.
Exciter Armature - The exciter armature or just the "exciter", generates electricity which is
used for excitation of the field coil. The field coil makes the magnetic field required to generate
electricity, which is used for the generators main power output.
Frequency - Frequency is the number of complete cycles per second in alternating current
direction. The standard unit of frequency is the hertz, abbreviated Hz. If a current completes
one cycle per second, then the frequency is 1 Hz; 60 cycles per second equals 60 Hz
Ground Fault Interrupters (GFI's) - These devices are designed to eliminate electrical shock
hazard resulting from individuals coming in contact with a hot AC line. The circuit interrupter is
designed to sense any change in circuit conditions. It is required by the NEC that all 12 volt,
single phase, 15- or 20 ampere receptacle outlets that are installed outdoors or in bathrooms
have ground fault interrupters connected to them
Heat Rise - Is in direct relation to the longetivity of the generator. To find out why Multiquip
units exceed the competition, see page 27
KVA – Kilo Volt Amp which sizes three phase loads can be converted to Kilowatts by
multiplying the KVA by the power factor 0.8
NEMA - National Electrical Manufacturers Association: For more information about NEMA and
their standards, visit their website at http://www.nema.org/.
Ohm - A unit of electrical resistance equal to that of a conductor in which a current of one
ampere is produced by a potential of one volt across its terminals.
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GENERATOR GLOSSARY
Phase Single Phase Power (typically 120V AC or 230V AC depending on the country) is carried
between two wires: live and neutral and sometimes a third ground wire for safety. The
frequency of AC voltage is 50 or 60 Hz depending on the country. Single-phase power is used
in very many applications, for example to power all typical home electrical appliances you use
single-phase power from a normal electrical outlet at home.
Three Phase Power is very common and is a more efficient use of conductors. Voltage is
carried through three conductors 120° out of phase with the other two. Three-phase power
provides a more efficient means of supplying large electrical loads like motors, and is used
more in industrial areas.
PMG - Permanent Magnetic Generator: Eliminates the excitation losses in the rotor, which
otherwise typically represent 20 to 30% of the total generator losses. It also gives a lower
temperature rise in the generator.
Rheostat - A continuously variable electrical resistor used to regulate current.
Voltage - the rate at which energy is drawn from a source that produces a flow of electricity in a
circuit. Expressed in volts (V)
Voltmeter - This feature serves as a convenient diagnostic tool on the jobsite. The operator
can quickly tell whether or not the generator is producing the correct voltage and prevent
overheating of tools and equipment.
Watt – An international system unit of power equal to one joule per second, the power
dissipated by a current of 1 ampere flowing across a resistance of 1 ohm.
A = Amps
W = Watts
kW = Kilowatts
vA = Volt amps
kVA = Kilovolt amps
1 Ø = Single Phase
3 Ø = Three Phase
V = Volts
dB = Decibels
Hz = Frequency (hertz)
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Corporate Headquarters • Multiquip Inc. 18910 Wilmington Ave. Carson, Ca. 90746
80
Multiquip Inc. ◦ DCA Series Generators ◦ Manual No. DCA25150CD
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