Onan YHB Generator Service Manual
Below you will find brief information for Generator YHB Generator. The Onan YHB generator is a two-pole, revolving field generator designed for 3000 (50 Hz) or 3600 (60 Hz) r/min operation. Excitation is provided with a brushless exciter mounted outboard of the generator. The generator rotor is directly coupled to the engine flywheel with a flexible drive disc. Engine speed determines generator output voltage and frequency.
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Generator
YHB
Generator with Torque Match4 Regulator'"
2-86
6
.
Printed in U S A .
Redistribution or publication of this document, by any means, is strictly prohibited.
Safety Precaytions
The following symbols in this manual highlight con- ditions potentially dangerous to service personnel, or equipment. Read this manual carefully. Know when these conditions can exist. Then take necessary steps to protect personnel as well as equipment.
This symbol warns of Immediate hazards which will result in severe personal Injury or death.
This symbol refers to a hazard or
@@!?%&I
in severe personal Injury or' death;
This symbol refers to a hazard or
@@@%I
personal Injury or product or property damage.
,
PROTECT AGAINST MOVING PARTS
Avoid moving parts'of the unit. Avoid use of loose jackets, shirts or sleeves due to danger of becoming caught in moving parts.
Make sure all nuts and bolts are secure. Keep power shields and guards in position.
If you must make adjustments while the unit is run-
' ning, use extreme caution around hot manifolds, moving parts, etc.
Do not work on this equipment when mentally or physically fatigued.
GUARD AGAINST ELECTRIC SHOCK
Disconnect electric power before removing protec- tive shields or touching electrical equipment. Use rubber insulative mats placed on dry wood platforms over floors that are metal or concrete when around electrical equipment. Do not wear damp clothing
(particularly wet shoes) or allow skin surfaces to be damp when handling electrical equipment.
Disconnect batteries to prevent accidental engine start. Jewelry is a good conductor of electricity and should be removed before working on electrical equipment.
Use extreme caution when working on electrical components. High voltages cause injury or death.
Follow all state and local codes. To avoid possible personal injury or equipment damage, a qualified electrician or an authorized service representative must perform installation and all service.
c
.
IAWARNING
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EXHAUST GAS IS DEADLY!
Exhaust gases contain carbon monoxide, an odorless and colorless gas. Carbon monoxide is poisonous and can cause unconsciousness and death. Symptoms of carbon monoxide poisoning can include:
0
Dizziness
Nausea.
,
Headache
Weakness and Sleepiness
0
0
0
0
Throbbing in Temples
Muscular Twitching
Vomiting
Inability to Think Coherently
IF YOU OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GETOUT
INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical atten- tion. Shut down the unit and do not operate until it has been inspected and repaired.
Protection against carbon monoxide inhalation includes proper installation and regular, frequent visual and audible inspections of the complete exhaust system.
ii
Redistribution or publication of this document, by any means, is strictly prohibited.
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Table of Contents
SECTION
1
2
3
4
5
6
TITLE PAGE
SAFETY PRECAUTIONS
INTRODUCTION
................................................................. ii
......................................................................
..................................................................
...............................................................
GENERATOR AND VOLTAGE REGULATOR
1-1
.......................................................................
Generator Description
.............................................
2-1
...............................................................
2-1
...........................................................
........................................................
.......................................................
GENERATORIREGULATOR TROUBLESHOOTING
......................................
...................................................................
............................................................ ...........
AC Output Voltage at Rated Engine Speed
..........................................................
Output Voltage Too High or Too Low
(A) Testing AC Residual Voltage
Unstable Voltage. Engine Speed Stable at Rated Speed
....................................
..............................................
Unbalanced Generator Output Voltage
...................................
GENERATOWREGULATOR TESTS/ADJUSTMENTS
....................................
.......................................................
................................................................
(C) Voltage Regulator VRAS-2 Replacement
...........................................
(D) Testing Rotating Rectifiers (Diodes)
................................................
4-2
. :
..............................................................
.............................................................
.........................................................
..........................................................
............................................................
(K) Voltage Regulator VRAS-2 Adjustment
.............................................
(L) Generator Voltage Adjust (R21)
....................................................
GENERATOR DISASSEMBLY/ASSEMBLY
WIRING DIAGRAMS
..............................................
..............................................................
................................................................
...................................................................
6-1 iii
Redistribution or publication of this document, by any means, is strictly prohibited.
c
Redistribution or publication of this document, by any means, is strictly prohibited.
Section 1 Introduction
.
ABOUT THIS MANUAL
This manual provides troubleshooting and repair infor- mation regarding the Onan series YHB generator in connection with a Torque Match-ll (VRAS-2) voltage regulator. For further operation, service, and trouble- shooting information regarding engine or controller components, refer to support manuals specific to your generator set.
Study all manuals carefully and observe all warnings and cautions. Knowing your generator set, using it properly, and following a regular maintenance sche- dule will result in longer unit life, better performance, and safer operation.
Repair information in this manual for printed circuit board components other than fuses is not extensive as solid state printed circuit boards lend themselves more to replacement than repair. Application of meters or hot soldering irons to printed circuit boards by other than qualified personnel can cause unne- cessary and expensive damage. Repair of the printed circuit boards is not recommended except by the factory.
High voltage testing or high poten-
LBCAUTIONJ
tial (or Megger) testing of generator windings can cause damage to solid state compo- nents. Isolate these Components before testing.
.
TEST EQUIPMENT
Most of the test procedures in this manual can be performed with an AC-DC multimeter such as a
Simpson Mode'l 260 VOM or a digital VOM. Some other instruments to have available are:
0
0
Onan Multitester
Jumper Leads
AC Voltmeter
DC Voltmeter
Wheatstone or Kelvin Bridge
See Onan Tool Catalog 900-0019.
HOW TO OBTAIN SERVICE
In the event the generator requires servicing beyond the scope of information contained in this manual, contact an Onan Distributor for assistance. Onan fac- tory trained Parts and Service representatives are ready to handle all your service needs.
When contacting an Onan Distributor, always supply the complete Model number and Serial number as shown on the Onan nameplate. The Onan nameplate
is
located on the side of the generator control box.
Y-1641
FIGURE 1-1. ONAN NAMEPLATE
I
AWARNING
INCORRECT SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN
SEVERE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE. SERVICE
PERSONNEL MUST BE QUALIFIED TO PERFORM ELECTRICAL AND/OR
MECHA NlCA L SERVICE.
1-1
Redistribution or publication of this document, by any means, is strictly prohibited.
,
Redistribution or publication of this document, by any means, is strictly prohibited.
Section 2. Generator and
Voltage Regulator
I
GENERATOR DESCRIPTION
The
YHB generator isa two pole, revolving field genera-
tor designed for 3000 (50 Hz) or 3600 (60
Hz) r/min operation. Excitation is provided with a brushless exci- ter mounted outboard of the generator. The generator rotor is directly coupled to the engine flywheel with a flexible drive disc. Engine speed determines generator output voltage and frequency. A centrifugal blower (on the drive disc) circulates discharged air through an
outlet in the blower end. See Figure 2-1.
As specified in Voltage/Current Options, Table 2-1 ,Volt- age Code 15 and 51 5 generators are reconnectible to provide the listed voltage options. Output rating is 0.8
PF. See Figure 2-2 and Table 2-1.
.
Five of the AC output leads extending from the stator housing are tapped with control wires (leads: 4,7,8,9 and
IO).
These control wires are routed into the control box
and used for control input and metering, Figure 2-3.
The brushless exciter stator mounts in the end bell while the exciter rotor and its rotating rectifier assemblies mount on the generator rotor shaft. Within the endbell, leads F1+ and F2- from the exciter stator winding are connected to the output terminals of the voltage regula-
END BELL
FIGURE 2-1. YHB GENERATOR
6-1159
Redistribution or publication of this document, by any means, is strictly prohibited.
7
220/380
3
9X 247/600
3
Y
GENERATOR
CONNECTION
SCHEMATIC
DIAGRAM
a f
IS
120/240 1
60
515
115/230
1 50
110/120 1 50
' Y
4
a
2
THIS DIAGRAM APPLIES TO 12 LEAD GENERATORS ONLY
D I A G R A M
GENERATOR C O N N E C T I O N W I R I N G
DIAGRAM
/
( W I T H CURRENT T R A N S F O R M E R S W H E N USEO)
L 1 1 2
LO
L O
12
T l T 2 T6 111 T O T 1 2 T 4 19 T S T 7 T 3 110
LO
L 1 1 2 ,
.
L 3
LO
12
T l T 1 0 16 17 12 111 14
18
T 3 112 TS .T9
LO
11
12 L 3
8
13
4 T 6 111
I5 110
112'l T7
T 2 18 T 3 T 9
LO
T 1 0 T l l T 1 2 11 77 T 4 T 2 T 8 15 13 19
11
NOTE This figure is for reference only. Refer to electrical schematic specific to your generator for further connection information.
FIGURE
2-2.
GENERATOR VOLTAGE CONNECTIONS
2-2
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Maximum Current (Amperes)
30kW 35kW 45kW 50kW
Parallel
Wye
.
Series
Wye
Code 515
110/190
115/200
120/208
127/220
110/220
115/230
220/380
230/400
240/416
254/440
Code 15
120/208
127/220
139/240
120/240
240/416
254/440
227/480
Code 7R*
220/380
50HZ
50Hz
50Hz
50Hz
50Hz
50Hz
50Hz
50Hz
50 Hz
50Hz
60Hz
60Hz
60Hz
60Hz
60Hz
60Hz
60Hz
114
108
104
99
99
94
57
54
52
49
-
-
-
-
-
-
-
-
-
-
121
115
105
105
152
145
139
131
131
126
76
72
69
66
174
164
150
150
X
X
X
X
X
X
X
X
X
X
X
60Hz
Code 9XR*
347/600 60Hz
*
-
Single-phase power can be taken in capacities up to full rated 3-phase kW
at 1.0
PF.
Broad range
alternators have 12 leads brought out
for user reconnect.
Series
Delta
X
X
X
CONTROL AND
METER LEADS
(TAPS OF
AC OUTPUT LEADS)
TO VOLTAGE
REGULATOR
CIRCUIT
THREE PHAS
FIGURE 2-3. THREE-PHASE GENERATOR SCHEMATIC
2-3
Redistribution or publication of this document, by any means, is strictly prohibited.
Optional Circuit
Breaker
Most Onan generator sets are installed for use with exterior circuit breakers and transfer switch equipment.
But, depending on customer requirements, an optional generator output circuit breaker might be mounted on side of generator box housing, Figure 2-4. Review the installation specifications for information regarding the addition of this circuit breaker. If so equipped, be sure to add its actuation
(ON
OFF) to your operating and troubleshooting procedures.
GENERATOR OPERATION
With the generator directly coupled to the engine fly- wheel, full rated output voltage is accomplished in a matter of seconds. The following briefly describes generator operation and voltage regulator interaction,
Refer to Voltage Regulation for further specifics regard- ing regulator operating modes.
*,
,
RFCTIFIERS'
1
BRUSHLESS EXCITER
FIELD
VOLTAGE
REGULATOR
FIGURE
2-5.
EXCITATION BLOCK DIAGRAM
2-4
LOAD
Redistribution or publication of this document, by any means, is strictly prohibited.
VOLTAGE REGULATOR DESCRIPTION
The design of the Torque Match-ll Voltage Regulator
VRAS-2) provides switch selections that alter its sens- ing and command signals in order to achieve maximum operating performance in a variety of generator sizes and applications. Review the following, then refer to
Voltage Regulator Adjustments for switch locationsand settings specific to your generator set model.
Operating
Modes
Torque-Matching:
In most applications, in order for the generator set to accept the application of a large momentary overload, such as motor starting, matching the torque characteristics of the engine and generator is required.
Because
of
the differences in engine characteristics, different torque matching may be used for. various engine/generator combinations. The switch-selectable design of theVRAS-2 provides Onan the flexibility to test and set the torque-matching function to best suit each enginelgenerator configuration.
When set to the proper torque-matching switch set- tings, the VRAS-2 voltage regulator is able to maintain output voltage, within reasonable limits, by reducing the voltage just enough to take full advantage of the engine’s full available power under transient conditions and prevent an unstable response.
Non-Torque-Matching:
Even though the voltage regula- tor can also be switch-selected to a non-torque- matching constant voltage mode, independent of engine speed, this mode will not prevent the generator set from stalling during momentary overload conditions, and is not recommended for use. Consult an Onan ser- vice representative before selecting this voltage regula- tion mode to ensure that load demands specific to your installation would not cause an unstable operation of the generator set.
Operating Stability
Because of the differences in exciter and main field time constants, different gain compensation is required for the various generator sizes and applications. The
VRAS-2 voltage regulator is switch-selectable to a kW range of operation that best suits the generator set application.
VOLTAGE REGULATOR ADJUSTMENTS
The VRAS-2 Voltage Regulator is shown in Figure 2-6.
There are threeswitches that require actuation and two potentiometers on the voltage regulator as follows:
0
Switch S1
-
Selects the overall range of operation for the regulator. Refer to Table 2-2.
0
Switches S2 and S3
-
Determine the mode of regula- tion (Torque-Matched, or Non-Torque-Matched).
Refer to Table 2-2.
0
Potentiometer R32
-
Provides adjustability to in- crease or decrease generator voltage to achieve proper setting.
0
Potentiometer R34
-
Is adjusted at the factory to set
.the frequency breakpoint, and does not require further adjustment.
2-5
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GENSET
MODEL
STABILITY
RANGE
SI-1 S1-2
60
HZ
TORQUE-MATCHING
REGULATION MODE
50 Hz
TORQUE-MATCHING
S2 S3-1 S3-2 S2
53-1 S3-2
NON-
TORQUE-MATCHING
52 S3-1 S3-2
SJB
SKI3
OFF
OFF
OFF POS2 OFF
ON
POS.2 OFF
ON POS2 ON
ON POS2 ON
ON
ON
POS2 OFF OFF
POS2 OFF OFF
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53
TB1-2. -3 AC INPUT VOLTS
TBI-3. -4 CROSS-CURRENT COMPENSATION
TB1-7, -8 VOLTAGE ADJUSTING RHEOSTAT
TB1-9, -10 EXCITER FIELD
F1
-TB1-9
F2
-
;R34
SG1516-2
FIGURE 2-6.
2-6
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Section 3. Generator/Regulatsu
Troubleshooting
CONTROL LOCATIONS
Review the following listing of component parts involved in generator troubleshooting. Because, the following Troubleshooting Flow Charts will only be calling them by name and not location.
Voltage Regulator
-
VRAS-2
Inside control box.
Terminal Board TB21: Inside control box.
Field Breaker CB21: On control box door.
Current Transformer CT21,22, and 2 3 Inside housing,
behind control box.
Rotating Rectifiers: Inside housing, beneath control
box.
-1
Accidental generator set starting can result in severe personal injury or death during service procedures. Disconnect battery cable before performing any checks on generator.
PREPARATION
A few simple checks and a proper troubleshooting procedure can locate the probable source of trouble and cut down service time.
1. Check all modifications, repairs, and replacements performed since the last satisfactory operation of the set to ensure that all generator leads are cor-
. rectly connected. A loose wire connection over-. looked when installing a replacement part could cause problems, as could an incorrect connection, an opened circuit breaker, or a loose connection on a printed circuit board. A thorough visual check can quickly eliminate these potential problems.
2. Visually inspect the components of Voltage Reg- ulator VRAS-2. Look for dust, dirt,
or
moisture and cracks in the printed solder conductors.
Burned resistors and arcing tracks are readily identifiable. Do not mark on PC boards with a pencil; graphite lines conduct and can cause leakage
or
short circuits between components.
3.
Visually inspect the exciter rotor assembly for burned components, broken wires, loose connec- tions, and carbon tracks caused by arcing between parts or between parts and ground. Also check for shorted paths between terminals caused by dust, dirt, and moisture.
Unless absolutely sure that panel instruments are accurate, use portable test meters for troubleshooting.
1 -
Ohmmeter checks must be made with the unit stopped to prevent meter damage.
TROUBLESHOOTING PROCEDURES
The information in this section is divided intoTrouble- shooting Flow Charts as follows:
A.
No AC Output Voltage at Rated Engine Speed.
6.
Unstable Output Voltage, Engine Speed Stable at
Rated Speed.
C.
Output Voltage Too High or Low.
D.
Exciter Field Breaker Trips.
E.
Unbalanced Generator Output Voltage.
To troubleshoot a problem, determine the problem and then refer to the appropriate troubleshooting flow chart. Start at the upper left-hand corner of chart, and answer all the questions with either a YES or NO.
Follow the chart until the problem is found, performing the referenced Adjustment and Test Procedures fol- lowing the flow charts.
.
The referenced components in the flow charts and in the Adjustment and Test Procedures can be found on the electrical schematic in Figure3-1, and on assembly and wiring diagrams.
This figure is for reference only. Use electrical schematic specific to your application when troubleshooting.
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--
FIGURE 3-1. ELECTRICAL SCHEMATIC
(Includes Detector AC Meter Option)
3-1
Redistribution or publication of this document, by any means, is strictly prohibited.
FLOW CHART A.
(fully-in position)? check continuity with ohmmeter.
Is
,
Push to reset breaker. Does generator
AC output voltage build up?
No
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c
If voltage is unstable, high or low, or causes breaker to trip.
see
Charts
B, C, D or
E.
. t
No
Flash exciter field per TEST generator output voltage build
up?
v
Is residual voltage across TB21-22 and
23 equal to 5 to 10 VAC or more per
TEST (A)?
<
Yes
I
I r e
~~
I
Is exciter field voltage across VRAS-
, to5 to lOVAC or
1 N o - l
more?
I
YeS
I v
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Check exciter field wiring for shorts per
TEST (J). Replace bad wiring.
Disconnect stator leads 7 and 8 from
TB21-22 and
23.
Is
residual
voltage across the leads 5 to 10 VAC or more
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Check lead continuity between !/IUS
2/T31-2 and Ti’ on
the
generator and between VRAS2frB1-3 and generator lead T8
as
per TEST (J).
I
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Check exciter field wiring for opens per
TEST (J). Replace bad wiring.
1
1
Replace voltage regulator VRAS-2 per
Check diodes CR1 through cR6 on rotor per TEST (D)- Replace if bad.
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1
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Do not replace Voltage Regulator
k@i!@@l
VRAS-2 until external trouble has been corrected to avoid possible damage to new regulator board.
Check exciter rotor winding per TEST
(F). Replace if bad.
+
Check generator rotorfield winding per
TEST (H). Replace if bad.
TEST (G). Replace if bad.
3-2
Redistribution or publication of this document, by any means, is strictly prohibited.
FLOW CHART B. UNSTABLE VOLTAGE, ENGINE SPEED STABLE AT RATED SPEED.
I
Are there anv broken wires or
~ loose
1 connectiongon voltage regulator assembly?'
Does voltage cycle from zero to rated
OUtDUt?
I '
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Check wiring harness from regulator assembly to end bell per Test
(J).
Check ok?
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Repair as required. Check control panel voltage adjust rheostat and replace if defective (open):
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Repair wiring or replace as required.
Check voltage regulator adjustment/ switch settings per adjustment
Check ok?
(K).
Yes
at no load to full load range of generator set?
Replace Voltage Regulator VRAS-2 per procedure (C).
Do not replace Voltage Regulator
VRAS-2 untll external trouble has been corrected to avoid possible damage to new regulator board.
FLOW CHART C. OUTPUT VOLTAGE TOO HIGH OR LOW.
I
Are generator output connections correct and secure?
NO-
Set r/min per instructions in appropriate engine manual.
-
Refer to Generator Description,
Optional Voltage Connections, and appropriate electrical schematic.
I
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Check voltage regulator adjustment/ switch settings per adjustment
(K).
Check ok?
NO
k
Check condition of rotating diodes.
.
I
Replace voltage regulator VRAS-2
N O
6
Is voltage within specifications at no load to full load range of generator set?
I
No
I
Test rotating diodes per TEST (D).
Replace if defective.
1 -
Do not replace Voltage Regulator
VRAS-2 untll external trouble has been corrected to avoid possible damage to new reg- ulator board.
3-3
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FLOW CHART D. EXCITER FIELD BREAKER TRIPS.
Does AC output voltage build up to 150% or more of rated voltage before breaker trips?
'
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*YO
t
Check diodes in rotor assembly per Test (D). Replace if bad.
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c
Check exciter stator winding per Test (E). Replace if bad. r
Check exciter rotor winding per Test (F). Replace if bad.
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1
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Check g e n e r a t o m winding per Text
(H).
if bad.
Check for any loose or broken wires or connections on VRAS-2 assembly.
t
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Check Voltage Regulator adjustments and connections per Test (K).
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Check generator stator leads for proper, and secure connection. Refer
. to Generator Description, Optional Voltage
Connections, and appropriate electrical schematic. per Test (G). Replace if bad.
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Replace voltage regulator VRAS-2 per procedure (C).
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.
3-4
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FLOW CHART E. UNBALANCED GENERATOR OUTPUT VOLTAGE
still unbalanced?
I
Yes
.
.
Check each phase for balanced current. redistribute load.
.. t
I
Check for correct. grounding of generator and load.
Is generator stator winding continuous per
TEST (G).
Replace stator assembly.
.
.
.
.
.
.
,
..
.
. .
.
.
.
. .
.
.
. .
_ .
.
.
. . .
.
.
3-5
Redistribution or publication of this document, by any means, is strictly prohibited.
..
Redistribution or publication of this document, by any means, is strictly prohibited.
Section
4.
GeneratoVRegulator
Tests/Ad justments
All of the following adjustments and tests can be per- formed without disassembly of the generator. They should be used for testing generator and regulator components in conjunction with the troubleshooting flow charts. All ohmmeter tests must be made with the unit stopped to prevent meter damage.
TESTING AC RESIDUAL VOLTAGE
Generator residual AC voltage should be checked first if there is no AC power output. A good place to check is at terminal block TB21, across terminals22 and 23. Resid- ual voltage should be 5 to 10 VAC at normal operating r/min. If none, flash the field following the instructions in
Test B.
If residual voltage is present at TB21, then check the continuity of circuit breaker CB21. If CB21 is okay, pro- ceed to voltage regulator VRAS-2 and check for resid- ual voltage between terminal numbers 2 and 3. If none, check continuity between these points with the genera- tor set shut down.
3. Check generator voltage, and shut down generator set. Restart generator set and run at no load. Unit must build up voltage without field flashing. If not, shut down generator set and perform continuity check of all related wiring.
With Generator Set Shut Down
1. Touch the positive battery lead to TB1-9 and the negative lead to TB1-10 of VRAS-2.
2. Hold the leads in place for no longerthan 5 seconds.
3. Start generator and run at no load. Unit must build up voltage without field flashing. If it does not, shut down generator set and perform continuity check of all related wiring.
Incorrect field flashing proce- dures can damage regulator.
Do not maintain field flash connection to exciter cir- cuit longer than 5 seconds.
FLASHING THE FIELD
If output voltage does not build up, it may be necessary to restore residual magnetism by flashing the field. This requires a 6-volt battery and a 12-ampere 300-volt diode wired as shown
A 3-volt source will also work, as will a 12- or 24-volt source. However, if a 12- or 24-volt source is used, a
2-watt, 20- or 40-ohm resistor, respectively, must be in series with the diode to drop the voltage to 6-volts.
Flashing the field can be accomplished with generator set operating or not. Either of the following procedures should be sufficient to restore residual magnetism.
With Generator Set in Operation
1.
Start the generator set and operate at normal rimin.
2. Touch the positive battery lead to TB1-9 of VRAS-2, and the negative lead to TBl -10. Hold the leads in place just long enough for the voltage to build up to the normal operating level, then remove the leads.
PLACE RESISTOR HERE FOR
12V OR 24V BATTERY
TO
VRAS-2
TB1
TERMINALS
1 0 4
'
12 AMP.
DIODE
I/souRcE
6 VOLT
D R Y CELL
0 A r r E R Y
FIGURE 4-1. FIELD FLASHING CIRCUIT
4-1
Redistribution or publication of this document, by any means, is strictly prohibited.
VOLTAGE REGULATOR
VRAS-2 REPLACEMENT
Use the following procedure for replacing the voltage regulator assembly:
1.
Stop the engine, and disconnect starter batteries.
2. Disconnect, and if necessary label the wires from
VRAS-2/TBl. Refer to AC control wiring diagram.
3.
Remove the mounting screws, replace old VMS-2 with new, and secure in place with mounting screws.
4. Reconnect wires removed in step 2 to proper terminals.
5. Perform voltage regulator adjustment/switch set- tings for specific voltage and method of regulation desired per procedure
(K).
TESTING ROTATING
RECTIFIERS (DIODES)
Two different rectifier assemblies make up the rotating
rectifier bridge assembly, Figure 4-2. Using an accurate
ohmmeter, test each CR using negative and positive polarities. Test rectifiers as follows:
1.
Disconnect all leads from assembly to be tested.
2.
Connect one lead to
F1+ stud and connect other
lead to CR1, CR2, and CR3 in turn; record resistance value of each rectifier.
3.
Connect one lead to
F2- stud and connect other lead to CR4, CR5, and CR6 in turn; record resistance value of each rectifier-
4.
Reverse ohmmeter leads from steps
2 3
record resistance value of each rectifier
F1
+to CR1,
CR2, and CR3’and F2- to CR4, CR5, and CR6.
‘.
....
5.
All the resistance readings should be high in one test and low in the other test. If any reading is high or low in both tests, rectifier assembly is defective.
6.
Replace defective rectifier assembly with new, iden- tical part.
Excessive dust or dirt on diodes andofher components will cause overheating and eventually iailure. Keep these assemblies clean!
Use 24 in.-lbs. (2.7 Nom) torque when replacing nuts of F1+ and F2-,
CR1, CR2, CR3, CR4, CR5, and
CR6.
DISCONNECT LEADS
ASSEMBLY TO
BE
.
FIGURE 4-2. ‘TESTING ROTATING RECTIFIERS
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...
.
.
.
I
,
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.
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.
4-2
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.
(E)
TESTING EXCITER STATOR
Testing
for
Grounds
Using an ohmmeter, R x 100 scale, measure the insula- tion resistance between either lead F1 or F2 and the
laminations, Figure 4-3. A reading
of less than infinity indicates a ground.
TESTING EXCITER ROTOR
Testing
for
Grounds
Connect leads of ohmmeter between each CR lead and exciter rotor laminations. Use an ohmmeter set at the highest resistance range. An ohmmeter reading less than one megohm (1,000,000 ohms) indicates defective ground insulation.
Testing
for
Open
or
Shorted Windings
Use a Wheatstone Bridge for this test. Disconnect main rotor field leads which connect to rotating rectifier assemblies at F1+ and F2-. Disconnect lead wires from diodes CR1, CR2, CR3, CR4, CR5 and CR6. Test between exciter lead pairs Tl-T2, T2-T3 and Tl-T3.
Resistance should be 0.6 to 0.7 ohms at 68OF (2OOC).
ES-1574
FIGURE 4-3. TESTING EXCITER FIELD
Testing Winding Resistance
Measure coil resistance between leads F1 and F2 with an ohmmeter scale
R
x 1. See Figure 4-4. Resistance
a \
\
WHEATSTONE
BRIDGE
FIGURE 4-4.. TESTING
EXCITER
FIELD
ES-1575
C R 3
CR4
* *
dR4
F2-
I
- Y
I
w
SCHEMATIC
OFEXCITER
WIR"G
CR2
T
A
CR5
Gll-1
FIGURE 4-5. TESTING
MCITER ROTOR
4-3
Redistribution or publication of this document, by any means, is strictly prohibited.
(GI
TESTING GENERATOR STATOR
Testing for Grounds
Before testing stator, disconnect control wire 4.7.8,
9, and 10 from TB21. Isolate from ground and each other.
Connect all stator output leads (Tl-T12) together.
Use an ohmmeter set on the R x 100 scale and mea- sure the insulation resistance between these wind- ings and the stator frame. A reading of less than infinity indicates a ground. Field circuit breaker can be either open or closed for this test.
11 TEST BETWEEN WIRE PAIRS
TI-LO, T2-LO. T3-LO
Testing for
Shorts
To
check for shorts between individual windings, first refer to electrical schematic to determine individual coil lead wires (Tl -T4, T7-T-10, etc.). Be sure to disconnect the instrumentation leads and stator leads'T4, T7, T8,T9, and T10. Connect an ohmmeter, R x 100 scale, to one lead of a stator winding (leaving the other end of coil winding being tested open), and the other ohmmeter lead to all other stator leads connected together.
Exam pie:
0
Ohmmeter lead to: T1 coil winding lead.
0
0
Ohmmeter lead to: T9,12,7,10,2,5,3,6,8, and 11 connected together.
Coil windings lead T4: Open
A reading of less than infinity indicates a short Repeat test for all six coils. .
Measure resistance
of
windings using a
Kelvin Bridge meter. Refer
Figure 4-6 and Table 4-1. If any windings
are shorted, open, or grounded, replace the stator assembly. Before replacing the assembly, check the leads for broken wires or damaged insulation.
Stator output,leads T4, T7, T8, T9 and T10 are inter- connected (within the stator) to five stranded #10 aircraft control wires. These wires are labeled 4,7,8,9, and 1O.respectively and terminate at TB21 (terminals
22-26).
'
C J r
TABLE 4-1. RESISTANCE VALUES FOR STATORS
All resistancesshould be within thevalues shown at25OC an accurate instrument such as
(77OF).
a
Kelvin Bridge for this test Test between the following coil leads.
T i -T4
T9-Ti2
T7-T10
T2-T5
T3-T6
T8-Tli
kW RATING
50Hz
'
45
55
THREE PHASE MODELS
TEST BETWEEN WIRE PAIRS
Tl-T4 T7-TlO T3-T6
T9-Tl2 T2-T5 TB-T11
FIGURE 4-6. TESTING STATOR WINDINGS
6-1165
RESISTANCE
Ohms @ 25°C (77OF)
0.083
f
0.070
f
0.036
f
5%
.
.
.
4-4
Redistribution or publication of this document, by any means, is strictly prohibited.
OHMMETER
TESTING GENERATOR ROTOR
Testing
for
Grounds
Use an ohmmeter (R x follows:
100
scale) and measure as
1. Disconnect F1 and
F2
rotor leads from the rotat- ing diodes.
.
2. Measure between either lead and the rotor shaft
3. A reading of less than infinity indicates a ground.
CONTACT ONE PROD TO EACH
FIELD LEAD
6-1167
FIGURE 4-8. TESTING ROTOR FOR AN OPEN CIRCUIT
CONTACT ONE PROD TO EACH OF THE FIELD
LEADS AND OTHER PROD TO ROTOR SHAFT.
IF ROTOR IS GOOD, THERE WILL
BE
ONE MEGOHM OR GREATER RESISTANCE.
FIGURE 4-7. TESTING ROTOR FOR GROUNDS
G-1166
WIRING HARNESS CHECK
Carefully check wiring harnesses as follows:
1.
Inspect all wires for breaks, loose connections, and reversed connections. Refer to applicable wiring diagram.
2. Remove wires from terminals at each end and
. using an ohmmeter, check wire end to end for continuity or opens.
3. Using an ohmmeter, check each wire against each of the other wires for possible shorts or insulation breaks under areas covered by wrap- ping material.
4. Reconnect or replace wires according to appli- cable wiring diagram.
Testing
for an
.Open Circuit
1.
Disconnect and test between F1 and F2 leads (Fig-
2. Refer to resistance values given in the following table.
TABLE 4-2. ROTOR RESISTANCES
3. Replace the rotor if it is grounded or has an open or short.
VOLTAGE REGULATOR (VRAS-2)
ADJUSTMENT
After replacement, voltage regulator VRAS-2 adjust- ment is performed as follows:
1.
Loosen locking nut of Voltage Adjust potentiometer,
R21. Locate adjustment screw to mid-position and retighten locking nut.
2. Open controller panel doors.
High voltages in the control
@@!%I
hazard which can cause severe personal injury or death. Proceed with care!
3.
Refer to Figure 2-6 Voltage Regulator for proper
Stability Range
(SI) S3)
switch settings.
4.
Ensure that all connections are proper and secure.
4-5
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5. Controller with Detector AC meter option: Refer also to adjustment (L).
Controller without Detector AC meter option: Con- nect an accurate voltmeter to VRAS/TB1-2 and
-3
terminals.
6. Start generator set.
7.
Using a screwdriver, turn R32 potentiometer on printed circuit board VRAS-2 to increase or decrease the voltage as required to achieve proper setting. Observe voltmeter while making adjust- ment. Set voltage with no load connected to genera- tor. (Example: For a 120/240 volt connection, set at no-load voltage for approximately 246 volts). If volt- age is unstable
or
tends to hunt, refer to trouble- shooting section.
8. Stop generator set, and prepare all installation and generator set controls for operation readiness.
Regulator Specifications
Input Power
Input voltage across terminals 2 and 4: 208 to 240 volts RMS +/-lo%, depending on wiring configu- ration.
Input frequency: 45 to 65 Hz
Maximum burden: 800 VA
Output Power
Continuous Rating: 3.0A
One minute rating: 6.5A (in current limit)
Current limit: 6.5A+/-0.75A
Minimum Field Resistance
0.6 ohms @ 25OC copper winding exciter
. .
Regulator Sensing
Single-phase average voltage ‘directly proportional to generator frequency to breakpoint. Independent of fre- quency after breakpoint Nominally set to 59 Hz (49
Hz for
50
Hz sets).
Operating Temperature
-40°C to +8OoC
GENERATOR VOLTAGE ADJUST
(R21)
The following procedure pertains to generator sets equipped with Detector AC option only.
1. Start generator set.
2. Prepare installation equipment for Test Without
Load.
3. Operate Phase Selector switch to read generator output current and voltage, while performing the following steps:
A. lnserta screwdriver into the Voltage Adjust con- trol on the front of the generator set control and carefully loosen the locking nut
B. Slowly turn the screwdriver clockwise to increase voltage, or counterclockwise to decrease voltage.
C. When set at correct voltage, tighten the lock- ing nut. Be careful not t o change adjustment.
If correct voltage cannot be attained by R21 adjustment, refer to VRAS-2 adjustment, proce- dure (K).
Observe that ammeter does not register any output current If output current is observed on the ammeter, contact an Onan representative.
4. Move the Phase Selector switch to the Off position.
5. Stop generator set, and prepare all installation and generator set controls for operation readiness.
4-6
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Section 5.
Generator
Disassembly/Assembly
GENERATOR DISASSEMBLY
If generator testing determines that the generator needs repair, remove and disassemble as follows:
1, Disconnect the negative (-) battery cable to prevent accidental starting of the generator set while servicing.
Accidental starting of the gen- erator set during this procedure presents the hazard of severe personal injury or death. Make sure to disconnect the negative baf- tery cable before beginning.
2.
Remove the generator output box cover, Figure 5-1.
3.
Disconnect the stator lead wires from the load wires.
4.
Disconnect lead wiresfrom control box. Check wire markings
for
legibility to ease assembly. Arrange leads so they can be easily withdrawn from the control box.
Disconnect all engine and generator control wire leads from inside control box as follows:
0
0
A1 1 /TB1-8,-10, and terminals -1 through -7 as required.
Unplug A l l /JlIJ2,J3, and J4.
AC Wiring
0
TB21-22 to -30.
5.
Remove overspeed switch assembly, Figure 5-2.
6. Use a hoist or similar lifting device to support the output box and control assembly.
-1
To prevent personal injury, use
adequate lifting devices to sup-
port heavy components. Keep hands and feet clear while lining.
.
SWITCH
CONTACTS
FIGURE 5-1. OUTPUT BOX AND CONTROL
SC-1441
5-1
AIR GAP
(NOT LESS THAN
0.005 IN.10.13
MM)
ADJUST
SCREW
ES-1488
FIGURE 5-2. OVERSPEED SWITCH
Redistribution or publication of this document, by any means, is strictly prohibited.
7.
Remove the endbell capscrews that secure the out- put box support brackets to the endbell; and remove the output box and control box as an assembly.
Refer to Figure 5-4 during generator disassemblyto identify and locate components.
8.
Disconnect the exciter stator lead wires (F1 and F2) from the terminal block on the endbell. Loosen the four screws that secure the exciter stator to the endbell and remove the exciter stator.
9.
Remove the rotor shaft capscrew, lock washer, overspeed switch, flat washers, and spacer from the end of the rotor shaft,
10.
Disconnect the generator lead wires from terminals
F1
and F2 on the exciter rotor, and remove the exciter rotor from the rotor shaft.
1 1.
Remove the bearing retainer capscrews and bear- ing retainer from the endbell.
12. Remove the remaining capscrews that secure the endbell to the stator housing, and remove endbell from stator. It might be necessary to tap around the joint to separate the endbell assembly.
13.
Remove the center capscrew, lock washer, and flat washer from the two generator vibration isolators.
14. Using an adequate lifting device, lift the generator until the mounting brackets clear the vibration isolators.
15.
Block the rear of the engine in place by supporting the flywheel housing. A length of steel channel and wooden blocking is required to support..the rear of the engine. Place the channel and blocking under the flywheel housing. Lower the generator until most of the set weight is supported by the blocking.
16. Remove the protective screening from the genera- tor air discharge openings and disconnect the grounding strap from the flywheel housing.
17.
Verify that the stator is adequately supported and then carefully remove the capscrews from the stator attachment ring.
'
18.
Remove the stator assembly, being careful not to drag the windings on the rotor. Place stator on its side in the horizontal position.
19. Using a hoist and sling to supportthe rotor, carefully remove the capscrews that secure the drive disc to the flywheel.
20. Remove the rotor assembly and place it on wood blocks in the horizontal position. To avoid possible distortion, do not allow the drive disc and fan to rest on anything.
21. Remove the capscrews that hold the drive disc to the rotor shait, and remove the drive disc, spacer, and rotor fan.
22. Use a gear puller to remove the end bearing from
5-3.
FIGURE 5-3. END BEARING REMOVAL
6-1161
5-2
Redistribution or publication of this document, by any means, is strictly prohibited.
5-3
6-1160
Redistribution or publication of this document, by any means, is strictly prohibited.
GENERATOR ASSEMBLY
Generator assembly is the reverse of disassembly procedure, refer to Figure 5-4.
1. Always replace bearing with a new one. Apply a layer of Molykote grease, Onan part #524-0118, to the inside diameter of the end bearing. Press bear- ing on to rotor shaft, applying force to the inner face of the bearing.
2. Place the rotor fan and spacer in position on the rotor shaft.
3.
Install the drive disc on the rotor shaft, placing the chamfered edge on the flywheel side. Install the eight capscrews and flat washers and tighten to 68 ft-lbs. (92 Nom) torque.
4. Using a hoist and sling to supportthe rotor, align the holes in the drive disc, fan spacer, and fan with the corresponding holes in the flywheel.
5. Secure the rotor assembly to the flywheel using eight capscrews and flat washers. Tighten to 35 ft-lbs. (48 Nom) torque.
6. Using an adequate lifting device, carefully move the stator into position over the rotor assembly. The stator leads should be in the3 o’clock position when viewed from the endbell.
7. Align the holes in the stator attachment ring with the holes in the flywheel housing and install the thirteen capscrews and lock washers. Tighten to 35 ft-lbs.
(48 Nom) torque.
8. Using an adequate lifting device, slightly raise the generator
so
that the wooden blocking and steel channel can be removed from under the flywheel housing; then lower the generator
so
the full weight is resting on the rear vibration isolators.
9. Place the Protective screeninn over the generator air discharge openings and fasten securely.
10.
Connect the grounding strap to the flywheel hous- ing using a capscrew and EIT locking washer; and tighten securely.
11.
Install the capscrew, locking washer, and flat washer in each vibration isolator; and tighten securely.
8
12. Apply a thin film of Molyokote grease or equivalent to the mating surfaces of the end bearing and the endbell bearing hole.
13. Install endbell on the stator, placing the opening for the stator leads in the 3 o’clock position. Fasten endbell using the four capscrews and lock washers but do not tighten.
14. Install the bearing retainer on the endbell and secure using four capscrews and lock washers.
Tighten to 4.5 ft-lbs. (6 Nom) torque.
15. Install the exciter rotor on the rotor shaft. Connect
’
, the generator lead wires to terminals F1 and the exciter rotor.
16. Install the exciter stator on the endbell and secure using four socket head capscrews and lock washers. Tighten to 4.5 ft-lbs. (6 Nom) torque.
17. Connect the exciter stator lead wires to terminals F1 and F2 on the endbell terminal block.
18.
Refer to Figure 5-2. Mount and adjust Mechanical
Overspeed Switch.
When installing the overspeed switch assembly
(capscrew, lock washer, switch, small flat washers, large flat washer, and spacer) on the rotor shaft, tighten to
53 ft-lbs. (72 Nom) torque.
Install the overspeed switch assembly bracket and secure using two capscrews and lock washers.
Tighten to 4.5 ft-lbs. (6 Nom) torque. Refer to Figure
19. Connect overspeed switch lead wire to terminal on overspeed switch bracket.
20. Remove the four capscrews and lock washers from the endbell. Use an adequate lifting device to hold the output box in position for mounting to the end- bell. Replace the capscrews and lock washers and tighten to 20 ft-lbs. (27
Nom)
torque.
21. Connect the wires using the proper generator set wiring diagram, and voltage connections, Figure
2-2.
22: Verify that all connections are proper and secure and then install the output box cover.
23. Connect the negative (-) battery cable and test the generator set for operation.
.
5-4
Redistribution or publication of this document, by any means, is strictly prohibited.
Section
6.
Wiring Diagrams
GenSet AC Control (61 2-6268)
GenSet AC Control (61 2-6267)
6-1
Redistribution or publication of this document, by any means, is strictly prohibited.
Y O L I A O E R E O U L A l O R
L E F T S l O B WALL l l N 5 1 0 E VIEW1
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Redistribution or publication of this document, by any means, is strictly prohibited.
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12-6267
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Redistribution or publication of this document, by any means, is strictly prohibited.
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Redistribution or publication of this document, by any means, is strictly prohibited.
Redistribution or publication of this document, by any means, is strictly prohibited.
Onan Corporation
1400 73rd
Avenue
Minneapolis,
M N
1 -800-888-ONAN
N.E.
55432
612-574-5000 International Use
Telex:
275477
Fax:
61 2-574-8087
Onan
is
a registered trademark of
Onan Corporation
Redistribution or publication of this document, by any means, is strictly prohibited.
Advertisement
Key features
- Brushless exciter
- Torque Match-ll Voltage Regulator
- Two-pole, revolving field
- 3000 (50 Hz) or 3600 (60 Hz) r/min operation
- Directly coupled to the engine flywheel
- Flexible drive disc
