MODEL
1204/5
MOTOR CONTROLLERS
© 2011 CURTIS INSTRUMENTS, INC.
1204 /1205 Manual, p/n 98690
Rev. C: February 2011
CURTIS INSTRUMENTS, INC.
200 Kisco Avenue
Mt. Kisco, New York 10549 USA
Tel. 914.666.2971
Fax 914.666.2188
www.curtisinstruments.com
CONTENTS
CONTENTS
1.
OVERVIEW ......................................................................1
2.
HARDWARE INSTALLATION ......................................3
Controller ...................................................................3
Throttle ......................................................................4
Other Hardware .........................................................6
Main contactor ....................................................7
Forward/reverse contactors ..................................7
Forward/reverse switches .....................................7
Keyswitch ............................................................8
Polarity protection diode .....................................8
Control wiring fuse .............................................8
Power wiring fuse ................................................8
3.
WIRING ...........................................................................9
Connections: Low Current .........................................9
Connections: High Current ........................................9
Wiring: Series Motors .................................................10
KSI .....................................................................10
Forward/reverse (with standard power wiring) .....11
Plug braking .................................................11
Freewheeling ................................................11
Forward/reverse (with alternate power wiring) .....12
Reversing with 4×SPDT contactors..............12
Mechanical reversing switch .........................13
Throttle pot .........................................................14
Standard potbox ..........................................14
Pots for twist-grip throttles ...........................14
Reduced speed operation ..............................15
Electronic throttle................................................16
Wiring: Permanent Magnet Motors ............................17
Installation Checkout .................................................20
4.
MAINTENANCE AND ADJUSTMENT........................22
Controller ...................................................................22
Potbox ........................................................................24
Curtis 1204/1205 Manual, Rev. C
iii
CONTENTS
5.
TROUBLESHOOTING AND BENCH TESTING ........25
Operational Notes ......................................................25
In-Vehicle Diagnostic Tests .........................................28
Bench Testing .............................................................32
6.
GLOSSARY: FEATURES AND FUNCTIONS ..............35
APPENDIXES
A. Functional Description of 1204/1205 Controllers ............A-1
B. Pulse Width Modulation....................................................B-1
C. Curtis WEEE & RoHS Statement ....................................C-1
D. Specifications ....................................................................D-1
iv
Curtis 1204/1205 Manual, Rev. C
FIGURES
FIGURES
FIG.
1
Curtis 1205 electronic motor controller ..........................1
FIG.
2
Mounting dimensions,
Curtis 1204/1205 controller ...........................................3
FIG.
3
Mounting dimensions,
Curtis potboxes PB-5, -6, -9, and -10 .............................5
FIG.
4
Curtis footpedal FP-2 .....................................................5
FIG.
5
Typical installation,
Curtis 1204/1205 controller ...........................................6
FIG.
6
Basic wiring for use with series motors ............................10
FIG.
7
Alternate control wiring, to provide freewheeling ............11
FIG.
8
Alternate power wiring, for reversing with
4×SPST contactors..........................................................12
FIG.
9
Alternate power wiring, for reversing with
mechanical forward/reverse switch arm ...........................13
FIG.
10
Standard throttle pot, 0–5kΩ ..........................................14
FIG.
11
Bi-directional twist-grip throttle with
10 kΩ center-tapped, 4-terminal pot ..............................14
FIG.
12
Bi-directional twist-grip throttle with
20 kΩ pot and controller with optional
5kΩ–0 throttle input ......................................................15
FIG.
13
Reduced speed operation (with standard 0–5kΩ pot) .....15
FIG.
14
Curtis electronic throttle (ET series) ...............................16
FIG.
15
Basic wiring for use with
permanent magnet (PM) motors .....................................17
Curtis 1204/1205 Manual, Rev. C
v
FIGURES
vi
FIG.
16
Alternate PM motor wiring, using
4×SPST contactors to provide freewheeling ....................18
FIG.
17
Preferred PM motor wiring for
freewheeling or dynamic braking ...................................18
FIG.
18
Adjustment pots ..............................................................23
FIG.
19
Guide to troubleshooting procedures ..............................27
FIG.
20
Setup for bench testing ...................................................33
FIG.
A-1
Block diagram, Curtis 1204/1205 controller ...................A-1
FIG.
B-1
Pulse width modulation ..................................................B-1
Curtis 1204/1205 Manual, Rev. C
1 — OVERVIEW
1
OVERVIEW
Curtis 1204 and 1205 electronic motor speed controllers are designed to
provide smooth, silent, cost-effective control of motor speed and torque
on a wide variety of industrial electric vehicles.
Fig. 1 Curtis
Model 1205
electronic motor
controller.
Model 1204 has
identical connections.
Like all Curtis 1200 series controllers, the 1204/1205 models offer superior
operator control of the vehicle’s motor drive speed. Key features of the
1204/1205 controllers include:
✓
Infinitely variable drive and brake control
✓
Power MOSFET design provides high efficiency (for reduced motor
and battery losses) and silent operation
✓
High pedal disable (HPD) function monitors throttle status during
turn-on and prevents operation until throttle has been returned to
neutral [optional feature]
✓
Thermal protection and compensation circuit provides both undertemperature and overtemperature cutback, as well as steady current
limit throughout the entire operating range
✓
Undervoltage cutback function protects against low battery voltage,
including low voltage caused by external loads
More Features ☞
Curtis 1204/1205 Manual, Rev. C
1
1 — OVERVIEW
✓
Pot fault circuit shuts off controller if pot wires open
✓
Simple installation with no adjustments required
✓
Tin-plated solid copper bus bars
✓
Push-on connectors for control wiring
Familiarity with your Curtis controller will help you to install and operate
it properly. We encourage you to read this manual carefully. If you have
questions, please contact the Curtis office nearest you.
☞
C AU T I O N
Working on electric vehicles is potentially dangerous. You should
protect yourself against runaways, high current arcs, and outgassing
from lead acid batteries:
RUNAWAYS — Some fault conditions could cause the vehicle to run
out of control. Jack up the vehicle and get the drive wheels off the
ground before attempting these procedures or any other work on
the motor control circuitry.
HIGH CURRENT ARCS — Electric vehicle batteries can supply very high
power, and arcs can occur if they are short circuited. Always open
the battery circuit before working on the motor control circuit. Wear
safety glasses, and use properly insulated tools to prevent shorts.
LEAD ACID BATTERIES — Charging or discharging generates hydrogen
gas, which can build up in and around the batteries. Follow the battery manufacturer’s safety recommendations. Wear safety glasses.
2
Curtis 1204/1205 Manual, Rev. C
2 — HARDWARE INSTALLATION
2
HARDWARE INSTALLATION
CONTROLLER
The controller may be oriented in any position, but the location should
be carefully chosen to keep the controller as clean and dry as possible.
If a clean, dry mounting location cannot be found, a cover must be
used to deflect dirt and water splash.
The controller should be fastened with four screws to a clean, flat
metal surface that provides an adequate heat sink. The mounting surface is
an integral part of the overall heatsinking of the controller, and affects its
ability to dissipate heat. The case outline and mounting hole dimensions
are shown in Figure 2. If your controller is an adjustable model, be sure
to mount it so as to allow access to the adjustment screws.
Although not usually necessary, a thermal joint compound can be used
to improve heat conduction from the case to the mounting surface.
Fig. 2 Mounting
16.5 (0.65)
146 (5.75)
dimensions,
Curtis 1204/5
controller.
7 (0.28) dia.
113 (4.45)
8 (0.33) dia.
130 (5.13)
22×19×3
(0.85×0.75×0.125)
6 (0.25)
male push-on,
3 plcs
133 (5.25)
MODEL 1204:
MODEL 1205:
174 (6.85)
225 (8.85)
70 (2.8)
1204: 19 (0.75)
1205: 44 (1.75)
3.3
(0.13)
Dimensions in millimeters and (inches)
Curtis 1204/1205 Manual, Rev. C
3
2 — HARDWARE INSTALLATION
THROTTLE
The standard controller throttle input is 0–5kΩ. Curtis potboxes (PB-5,
-6, -9, -10) are designed to match this input. Some of these potboxes have
a built-in microswitch, eliminating the need to install a separate pedalactuated microswitch. Curtis also offers a self-contained footpedal unit
(FP-2) that eliminates the need for fabricating and installing a pedal-potbox
linkage. Any potbox that provides a nominal 0–5kΩ output (controller
output begins at ≈300 ohms, full output is ≈4400 ohms) will work with
the standard throttle input. For other types, contact your Curtis office.
If a Curtis potbox is used, it must be mounted so as to allow connection between the potbox lever arm and the vehicle accelerator linkage. The potbox mounting dimensions are shown in Figure 3. The lever
arm provides a series of holes so that the accelerator pedal “throw” can
be converted into the correct amount of potentiometer rotation. Use of
a second return spring on the pedal, in addition to the potbox return
spring, is required to prevent an uncontrollable full-on throttle input
(which could happen if there was a single spring, and it broke). If the
self-contained potbox spring is insufficient to return the pedal by itself,
two additional pedal return springs must be used.
It is also required that the accelerator pedal hit a mechanical stop at
its full-on position just before (≈1 mm [1/32"–1/16"]) the potbox lever
hits its own full-on stop. This mechanical stop will prevent the potbox
lever arm from bending if undue force is put on the pedal. Protection
of the potbox from water and dirt will help avoid problems of corrosion
and electrical leakage.
After the potbox has been mounted, operation of the pot can be tested
by measuring the resistance between the two wires with an ohmmeter.
With the pedal not applied, the resistance should be less than 50 ohms.
As the pedal is applied, the resistance should rise smoothly until it reaches
a value between 4500 and 5500 ohms. Values below 4500 ohms may
cause a reduction in efficiency and top speed. Values above 7000 ohms
indicate a defective potbox, and will cause controller shutdown.
Curtis’s electronic throttle (ET-XXX) is designed for 24–36V systems,
and can be used with any 1204/1205 controller having the 0–5V throttle
input option.
4
Curtis 1204/1205 Manual, Rev. C
2 — HARDWARE INSTALLATION
Fig. 3 Mounting
45°
42 (1.65)
dimensions,
Curtis potboxes
PB-5, -6, -9, and -10.
10 (0.38)
60
(2.37)
32
(1.25)
6
(0.25)
52 (2.06)
89 (3.5)
102 (4.0)
RIGHT-HAND OPERATION
LEFT-HAND OPERATION
N.C. N.O. COM.
COM. N.O. N.C.
WITH MICROSWITCH: PB-6
WITHOUT MICROSWITCH: PB-5
WITH MICROSWITCH: PB-9
WITHOUT MICROSWITCH: PB-10
Dimensions in millimeters and (inches)
112 (4.4)
1.8 m
(6 ft)
244 (9.6)
≈15 °
GRN
(not used)
ON
BLK
112
(4.4)
WHT
N.O.
WIRING:
BLACK = throttle input
WHITE = throttle input
BLUE = switch, common
ORANGE = switch, normally
Dimensions in millimeters and (inches)
open
(GREEN is not used with
1204/1205 controllers)
COM.
BLU
ORG
Fig. 4 Curtis footpedal FP-2.
Curtis 1204/1205 Manual, Rev. C
5
2 — HARDWARE INSTALLATION
OTHER HARDWARE
The recommended hardware for a typical 1204/1205 controller installation is shown in Figure 5.
Contactors should be mounted in a clean, dry location. If such a
location is unavailable, a cover should be used to deflect dirt and water
splash.
The precharge resistor connected to the main contactor, and the coil
suppression diodes connected to the main contactor and to the forward/
reverse contactors, are somewhat delicate components. Care should be
taken to prevent damage to them during installation.
CONTROL
WIRING
FUSE
POTBOX
KEYSWITCH
FORWARD/REVERSE SWITCH
(SPDT, center off)
POLARITY
PROTECTION
DIODE
COM.
POWER
WIRING
FUSE
N.C.
(250Ω, 5W)
F
R
F/R CHANGEOVER CONTACTOR
(Albright DC182 shown)
B+
MAIN
CONTACTOR
(Albright
SW180
shown)
FWD
BM-
BATTERY
REV
B+
A2
A1
B-
A2
S1
S2
PRECHARGE RESISTOR, such as Curtis PMC p/n MP-2
COIL SUPPRESSION DIODE, such as Curtis PMC p/n MP-1
SERIES
MOTOR
Fig. 5 Typical installation,
Curtis 1204/1205 controller.
6
Curtis 1204/1205 Manual, Rev. C
2 — HARDWARE INSTALLATION
Main Contactor
Most applications use a main contactor in series with the battery positive
(B+) cable to disconnect all power when the system is turned off, as shown
in Figure 5. A heavy-duty single-pole, single-throw (SPST) contactor
with silver-alloy contacts is recommended, such as an Albright SW80 or
SW180 (available from Curtis).
A coil suppression diode, such as a Curtis p/n MP-1 (which is rated
at 100 volts, 3 amps), should be used on the contactor coil.
The rapid charging of the controller’s internal filter capacitors causes
a high inrush current to flow briefly when the contactor closes. To extend
contact life, a precharge resistor, such as Curtis’s p/n MP-2, is recommended; the resistor precharges the capacitors and reduces the inrush
current through the contacts. If an inexpensive “can” type solenoid is
used, the resistor is mandatory to prevent contact welding.
Forward/Reverse Contactors
The forward/reverse contactor coils must match the vehicle’s battery
voltage. Use of two single-pole, double-throw (2×SPDT) contactors is
recommended. Although inexpensive “can” type solenoids can be used,
their ratings are typically not sufficient for long life. Changeover contactor
sets—such as the Albright DC88 and DC182 (available from Curtis)—are
therefore recommended.
A coil suppression diode, such as a Curtis p/n MP-1 (which is rated
at 100 volts, 3 amps) should be used on each of the forward/reverse
contactor coils.
Forward/Reverse Switches
The forward/reverse contactor coils can be operated by any type of
single-pole, double-throw (SPDT) center-off switch capable of switching
the coil current. Toggle or rocker switches are generally used.
If your controller has the optional high pedal disable (HPD) feature
and you plan to wire it for freewheeling, the best switch to use is a doublepole, double-throw (DPDT) “hesitation switch”— a toggle switch with
a mechanism that forces it to stop in the center (neutral) position before
going into the opposite direction. If a standard switch is moved quickly
from one direction to the other, it may not be in neutral long enough to
actuate HPD, and the motor will plug brake instead of freewheeling. The
switch must be in neutral for several milliseconds to actuate HPD.
Curtis 1204/1205 Manual, Rev. C
7
2 — HARDWARE INSTALLATION
Keyswitch
The vehicle should have a master on/off switch to turn the system off
when not in use. A keyswitch is typically used for this purpose.
Polarity Protection Diode
For polarity protection, a diode should be added to the control circuit.
This diode must be sized appropriately for the maximum total contactor
coil currents.
Control Wiring Fuse
To protect the control circuitry from accidental shorts, a small fuse
(typically 10 amps) connected in series with the B+ feed to the control
circuitry wiring is recommended.
Power Wiring Fuse
To protect the power wiring circuit, a fuse appropriate for the controller’s
rated current (see Appendix D) is recommended.
8
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
3
WIRING
CONNECTIONS: Low Current
Three 1/4" push-on terminals are provided
for the low current connections to the KSI
and throttle inputs.
For the control wiring, 0.75 mm2 (#18
AWG) vinyl insulated stranded wire is recommended.
KSI
throttle
inputs
1
2
3
CONNECTIONS: High Current
Four tin-plated solid copper bus bars are provided for the high current
connections to the battery and motor:
B-
B+
M-
A2
M- output to motor field
B- negative connection to battery
B+ positive connection to battery and
to motor armature
A2 plug diode to motor armature
The cables used for the battery and motor
connections must be heavy enough to carry
the high current required. A minimum size of 25 mm2 (#4 AWG) is
recommended. Rubber insulated welding cable is convenient to work
with because of its flexibility.
Connections to the controller bus bars should be made with lugs
suitable for the cable used, fastened by M8 (5/16") bolts and nuts. When
tightening the bolts, two opposing wrenches should be used. Failure
to use the double-wrench technique could cause undue strain to be placed
on the internal connections, and could also result in cracked seals around
the bus bars.
Curtis 1204/1205 Manual, Rev. C
9
3 — WIRING
CONTROL WIRING
FUSE
POWER WIRING
FUSE
KEYSWITCH
INTERLOCKS
PEDAL
MICROSWITCH
POLARITY
PROTECTION
DIODE
MAIN
F
R
PRECHARGE RESISTOR
(250 Ω, 5 W)
S1
–
POTBOX
R
REVERSE
F
A1
FORWARD
A2
MAIN
+
S2
R
F
BM-
B+
A2
Fig. 6 Basic wiring configuration,
Curtis 1204/1205 controller.
WIRING: SERIES MOTORS
Figure 6 is a schematic of the configuration shown in Figure 5. Wired
this way, the vehicle will plug brake if the direction is changed with the
vehicle moving and the throttle applied. Reversing is accomplished via
two single-pole, double-throw (2×SPDT) contactors. Coil suppression
diodes should be used on the main and forward/reverse contactors.
KSI Wiring
The keyswitch input (KSI) circuit includes input from the keyswitch
and from the various interlocks. The controller KSI is used to turn the
controller on and off. KSI is turned on by connecting it to battery B+.
Any positive voltage greater than about 8 volts will turn on the controller, but usually the full vehicle battery voltage is used. KSI draws only a
very small current (a few mA).
In its simplest form, KSI is operated by a keyswitch that turns the
vehicle off and prevents unauthorized use. The keyswitch should also
10
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
turn off the main contactor and the forward/reverse contactors. This will
act as a safety feature by removing power from the motor control system
when the keyswitch is turned off.
Interlocks (seat switches, battery charger interlocks, etc.) should be
wired in series so that they turn off the controller KSI and the contactors.
Forward/Reverse Wiring (with standard power wiring)
These forward/reverse wiring schemes assume the standard power wiring
(shown by the heavy lines in Figure 6). Some vehicles, especially those
previously using older, resistor-type controllers, may reverse the motor
armature rather than the field winding. Be careful if you are replacing this
type of controller. When using the Curtis controller it is essential that
the field be reversed and that the armature be connected directly to
the controller’s B+ and A2 terminals, because the plug diode inside
is connected to these terminals.
Plug braking
The standard forward/reverse control wiring (shown by the light lines
in Figure 6) provides plug braking. The forward/reverse switch should
be in the positive feed to the contactor coils, so that they can be turned
off by the keyswitch, interlocks, and pedal microswitch. The coil of one
contactor or the other is energized to select the direction desired.
Freewheeling (wiring to inhibit plug braking)
If your controller has the HPD option, this feature can be used to inhibit
plug braking by briefly turning off the controller’s KSI when the forward/
reverse switch goes through neutral. As shown in Figure 7, another set of
+
KEYSWITCH
INTERLOCKS
F/R SWITCH
(DPDT, center off)
POLARITY
PROTECTION
DIODE
–
BM-
Curtis 1204/1205 Manual, Rev. C
PEDAL
MICROSWITCH
REVERSE
FUSE
FORWARD
for inhibiting plug
braking, in order to
allow freewheeling.
MAIN
Fig. 7 Control wiring
B+
A2
11
3 — WIRING
contacts is added on the forward/reverse switch. Therefore, a double-pole,
double-throw (DPDT) center-off switch must be used for this setup. A
“hesitation switch” is recommended, to ensure the switch is in neutral
long enough to actuate HPD and inhibit plug braking.
Plug braking can be reactivated during freewheeling by releasing the
throttle and reapplying it.
Forward/Reverse Wiring (with alternate power wiring)
The basic wiring scheme in Figure 6 shows reversing via two single-pole,
double-throw (2×SPDT) contactors. Your vehicle may be configured for
a different type of reversing. Two alternative power wiring schemes are
described below—reversing with four single-pole, single-throw (4×SPST)
contactors, and reversing mechanically rather than electrically.
Power wiring for reversing with 4×SPST contactors
It is possible to use four single-pole, single-throw (4×SPST) contactors,
wired as shown in Figure 8. However, this configuration has the disadvantage that if any one of the contactors sticks closed, the motor field is
effectively shorted out in one drive direction. The motor will not turn,
and it may be damaged if operated like this for long.
Other disadvantages are that four, rather than two, contactors must
be mounted and wired, and that the coils draw twice as much power.
The control wiring options for the 4×SPST contactors are the same as
for the 2×SPDT contactors (see Figures 6 and 7).
As previously noted in the section on standard power wiring, when
using the Curtis controller it is essential that the field be reversed
and that the armature be connected directly to the controller’s B+
and A2 terminals, because the plug diode inside is connected to these
terminals.
Fig. 8 Power wiring
for reversing with
4×SPST contactors.
MAIN
FUSE
+
PRECHARGE RESISTOR
(250 Ω, 5 W)
–
12
F
R
R
F
S1
A2
A1
S2
BM-
B+
A2
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
Power wiring for mechanical reversing switch (golf car type)
As shown in Figure 9, this type of switch mechanically interchanges the
two motor field cables by rotating a movable contact bar. The configuration
shown is typical; many variations are in use.
Fig. 9 Power wiring
for reversing
with mechanical
forward/reverse
switch arm.
MAIN
FUSE
+
PRECHARGE RESISTOR
(250 Ω, 5 W)
S1
A2
A1
S2
–
BM-
Curtis 1204/1205 Manual, Rev. C
B+
A2
13
3 — WIRING
Throttle Pot Wiring
Standard potbox wiring
If the throttle input to the controller is from a Curtis potbox or footpedal,
the wiring is simple: just connect the two wires of the potbox/footpedal
cable to the two push-on terminals of the controller, as shown in Figure 6.
It doesn’t matter which wire goes on which terminal. The wires can be
extended as required.
Any suitable potentiometer of 5 kΩ nominal resistance will work
with the standard throttle input of the 1204/1205 controllers. As shown
in Figure 10, connection should be made to the wiper and to one outer
terminal of the pot so that resistance increases as the accelerator is applied.
Fig. 10 Standard
throttle pot, 0–5kΩ.
0–5kΩ POT
FASTER
0–5kΩ POT
TO
THROTTLE
INPUT
TO
THROTTLE
INPUT
FASTER
Pots for twist-grip throttles
Fig. 11 Bi-directional
twist-grip throttle with
10 kΩ center-tapped,
4-terminal pot.
14
Twist grip throttles either twist in only one direction (and are used only
for acceleration), or they twist both ways (and are also used for reversing,
by means of microswitches that select a direction contactor). For twist
grips that twist in only one direction, the controller throttle input can
be from a 5 kΩ pot as shown above in Figure 10.
For twist grips that twist both ways, a pot capable of going from
zero in neutral to 5 kΩ in each direction can be used. A mechanism can
be designed to make a standard pot turn in the same direction regardless
of which direction the twist grip is
FASTER
turned. Alternately, a 4-terminal,
5 kΩ
center-tapped 10 kΩ pot can be
coupled directly to the twist grip,
TO
as shown in Figure 11.
THROTTLE
5 kΩ
INPUT
A third method of accomFASTER
modating bi-directional twist grip
throttles uses a standard potentiometer and a controller with a
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
Fig. 12 Bi-directional
twist-grip throttle with
a standard 20 kΩ pot
and a controller with
the optional 5kΩ–0
throttle input.
nonstandard throttle input. As shown in Figure 12, a standard 20 kΩ pot is
used, with its end terminals wired together. The resistance goes from 5 kΩ
at neutral to zero at the extremes — the opposite of the standard throttle
input configuration. Contact the factory if you need
SPEED
this type of controller.
INCREASES
BOTH WAYS
20 kΩ
TO
THROTTLE
INPUT
WARNING: with the input circuit shown in Figure 12, potentiometer or wiring open circuits turn off the controller’s
output. However, pot wiring shorts appear the same as a
normal zero ohm signal to the controller, and will produce
full speed operation if the short occurs while the power is on.
Reduced speed operation
Vehicle top speed can be easily limited, for safety or other reasons. A single
resistor connected in parallel with the throttle pot will reduce maximum
speed according to its resistance value, as shown in Figure 13. Use of
a variable resistor makes adjustment of maximum speed easier. With a
switch, speed can be limited in reverse only, or the speed reduction can
be switched off—for example, to allow authorized personnel to run the
vehicle outdoors at full speed.
The speed reduction shown in the curve is approximate. The actual
vehicle top speed will depend on the motor characteristics and the vehicle
Fig. 13 Reduced speed
operation (with standard 0–5kΩ pot).
0–5kΩ
FASTER
OPTIONAL
SWITCH
SPEED
REDUCTION
RESISTOR
TO
THROTTLE
INPUT
SPEED REDUCTION RESISTOR
(k ohms)
25
20
15
10
5
0
0
20
40
60
80
100
APPROX. % OF ORIGINAL TOP SPEED
Curtis 1204/1205 Manual, Rev. C
15
3 — WIRING
load. You should determine by experiment the proper resistor value to
give the desired speed reduction. (NOTE: with reduced speed operation,
only top speed is reduced; full power is maintained for starting at low
speeds.)
Unlike resistor controllers, Curtis 1204/1205 controllers operate
efficiently in the reduced speed mode, because little power is lost through
the controller.
Electronic Throttle Wiring
Curtis’s electronic throttle, ET-XXX, is wired as shown in Figure 14. It
requires a controller with the optional 0–5V throttle input.
Fig. 14 Curtis electronic
throttle (ET series) with
a controller having the
optional 0–5V throttle
input.
WHT/BRN
GREEN
ORANGE
BLACK
BLACK/WHITE
WHITE
16
POLARITY
PROTECTION
DIODE
BM-
B+
A2
REVERSE
–
INTERLOCKS
FORWARD
+
KEYSWITCH
MAIN
FUSE
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
WIRING: PM MOTORS
Wiring for controllers in vehicles with permanent magnet motors is the
same as in those with series motors, except for the forward/reverse circuit.
PM motors have only two terminals: the armature brushes. The magnetic
field is provided by the permanent magnets and cannot be reversed; instead,
the motor is reversed by interchanging the armature leads.
The PM motor must be connected, via the forward/reverse circuitry,
to the controller’s B+ and M- bus bars. If your controller is designed for
use with either series or PM motors, it will have an A2 bus bar which
you should leave unconnected. If your controller is designed for use only
with PM motors, it will have no A2 bus bar.
Basic PM motor wiring—using two single-pole, double-throw
(2×SPDT) contactors—is shown in Figure 15. Note that when the
forward/reverse switch is in the neutral position, neither of the direction
contactors is operated and the motor is shorted. This will produce sudden
braking if neutral is selected while the vehicle is moving, or if the motor
is reversed while the vehicle is moving. The motor acts as a generator, and
will effectively be shorted out by the freewheel diode inside the controller.
The faster the vehicle is moving when the motor is shorted out, the more
CONTROL WIRING
FUSE
POWER WIRING
FUSE
KEYSWITCH
INTERLOCKS
PEDAL
MICROSWITCH
POLARITY
PROTECTION
DIODE
MAIN
F
+
R
POTBOX
REVERSE
R
FORWARD
F
MAIN
PRECHARGE RESISTOR
(250 Ω, 5 W)
PM
–
F
R
B-
B+
M-
Fig. 15 Basic wiring for use with PM motors.
Curtis 1204/1205 Manual, Rev. C
17
3 — WIRING
violent the effect of the sudden braking will be. If violent braking is not
acceptable for your application, use one of the wiring schemes described
below to allow the motor to freewheel in neutral or whenever the pedal
is released. However, note that sudden braking will still occur if the
opposite direction is selected and the pedal is re-applied while the
vehicle is still moving.
A partial solution is to arrange four single-pole, single-throw (4×SPST)
contactors to open the motor circuit whenever the pedal is released. This
arrangement, shown in Figure 16, causes the vehicle to freewheel in neutral
or whenever the pedal is released. The drawback to this scheme is that if
one of the contactors sticks closed, the controller’s output is shorted and
the controller may be damaged. For this reason, we do not recommend
the 4×SPST arrangement — although it is widely used.
+
(See Fig. 15 for overall wiring)
Fig. 16 PM mo-
controller B+
F
F
R
REVERSE
F
R
REVERSE
PM
FORWARD
R
FORWARD
tor wiring to provide
freewheeling, using
4×SPST contactors.
Although this
configuration is widely
used, we do not recommend it.
-
MPOWER WIRING
CONTROL WIRING
A better approach — and the one we recommend — is shown in
Figure 17. The motor is reversed by the two single-pole, double-throw
(2×SPDT) contactors. A third contactor (SPST) opens the motor circuit in
neutral or when the pedal is released, allowing the motor to freewheel.
controller B+
R
M-
REVERSE
PM
F
R
R
POWER WIRING
18
F
FREEWHEEL or DB
F
+
FREEWHEEL or
DYNAMIC BRAKE
(See Fig. 15
for overall wiring)
DYNAMIC BRAKING
RESISTOR (optional)
FORWARD
Fig. 17 Preferred PM
motor wiring to allow
freewheeling, using
2×SPDT direction
contactors with a third
contactor (SPST).
A resistor can be
added across the third
contactor to provide dynamic braking instead
of freewheeling.
CONTROL WIRING
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
If you prefer dynamic braking to freewheeling, you can install a
dynamic braking resistor. The motor generates power in slowing down
the vehicle; the dynamic braking resistor dissipates this power as heat.
The amount of braking torque is determined by the resistance, and is
proportional to the vehicle’s speed. The resistor gets hot and must be
sized and mounted accordingly. (NOTE: The size of the motor and the
amount of braking desired are factors in determining the appropriate
dynamic braking resistor; contact Curtis for guidelines.) The N.O. and
N.C. contacts of the forward/reverse contactors must be wired as shown
in Figure 17 or this scheme will not work.
Note that in all the PM motor wiring schemes shown (i.e., Figures
15–17), the forward/reverse switch is double-pole, double-throw (DPDT)
center-off. In addition to operating the forward/reverse contactors, the
switch turns on the controller’s KSI and main contactor when forward
or reverse is selected. By turning off the KSI in the neutral position,
the controller’s HPD feature will inhibit the controller output if the
forward/reverse switch is changed with the pedal depressed. While this
will not prevent the braking effect of reversing direction with the vehicle
moving, it will at least keep the motor from being driven in the opposite
direction.
A forward/reverse interlock module (Curtis p/n 1301) is available
for 24–36V models to prevent reversing direction while the vehicle is in
motion. This module allows the contactors to be reversed only when the
motor’s back EMF has come down to a preset level. Contact Curtis for
Application Notes providing further information.
Curtis 1204/1205 Manual, Rev. C
19
3 — WIRING
INSTALLATION CHECKOUT
Carefully complete the following checkout procedure before operating
the vehicle. If a step does not test correctly, use the troubleshooting guide
(Section 5) to identify the problem.
☞
C AU T I O N
Put the vehicle up on blocks to get the drive wheels off
the ground before beginning these tests.
Don’t let anyone stand in front of or behind the vehicle
during the checkout.
Make sure the keyswitch is off and the vehicle is in
neutral before beginning.
Wear safety glasses and use well-insulated tools.
A. Connect the battery. Use a voltmeter to verify that the proper voltage
and polarity appears at the battery B+ and B- terminals.
B. Check the voltage at the controller B+ and B- bus bars. If your
system has a precharge resistor in parallel with the main contactor, you
should see approximately 90% of the full battery voltage. If your system
does not have a resistor, temporarily connect one (100 to 200 ohms, 5
watts, or a 100 watt light bulb). The voltage at the controller should rise
to approximately 90% of the full battery voltage.
C. If “A” and “B” do not check out, troubleshoot the wiring connections. Do not turn on the keyswitch until the trouble is corrected and
“A” and “B” check out.
D. With the forward/reverse switch in neutral, turn on the keyswitch. If
the motor runs without the throttle being applied, turn the keyswitch off
and recheck the wiring. If the motor does not run without the throttle
applied, proceed with the checkout. Select a direction and slowly apply
the throttle; the motor should now respond.
E. Look to see which direction the wheels are turning. If the wheels
are going the wrong way, turn everything off and interchange the motor
field connections.
F. If you have HPD, check it next. Turn off the keyswitch and direction switch. Apply the throttle, turn the keyswitch on, and then select a
20
Curtis 1204/1205 Manual, Rev. C
3 — WIRING
direction. The motor should not run. Release the throttle and re-apply
it—the motor should now run. If the motor runs before you release the
throttle, recheck the wiring.
G. Take the vehicle down off the blocks and drive it in a clear area. It
should have smooth acceleration and good top speed.
H. On vehicles that are intended to plug brake, test the plug braking
by driving forward at moderate speed and shifting into reverse without
letting up on the throttle. The vehicle should smoothly brake to a stop
and accelerate in reverse.
I. On vehicles that are intended to have plug braking inhibited, verify
that the maneuver in “H” produces freewheel coasting.
Curtis 1204/1205 Manual, Rev. C
21
4 — MAINTENANCE & ADJUSTMENT
4
MAINTENANCE & ADJUSTMENT
Curtis 1204/1205 controllers and potboxes require only minimal maintenance if properly installed. NOTE: The controllers are sealed and thus
are not field serviceable.
CONTROLLER
Maintenance
☞
C AU T I O N
It is recommended that the following two steps be performed occasionally. First remove power by disconnecting the battery, and discharge
the capacitors in the controller (with a light bulb or a 2–10 Ω, 25 W
resistor connected for a few seconds across B+, B-). Follow good safety
practices: get the vehicle drive wheels off the ground, wear safety glasses,
and use insulated tools (see page 2).
1. Make sure the electrical connections to the controller (and to the
motor, contactors, etc.) are tight. When checking the controller
bus bar connections for tightness, use two opposing wrenches.
This double-wrench technique will help avoid putting stress on
the bus bars, which could crack the seals. Always use insulated
wrenches.
2. Inspect all seals at the front and back of the controller. If necessary,
use a moist rag to wipe these areas clean enough so that you can
see the seals. Look for cracks and other signs of seal damage.
If the seals are intact, clean the controller thoroughly either
by washing it off or by wiping it clean with a moist rag. Power
must not be reapplied until the controller terminal area is
completely dry.
If the seals have been damaged, there are several possible causes.
Perhaps the double-wrench technique was not used when the
cables were installed. Perhaps the vehicle’s environment requires
that the controller be better protected: either by mounting it in
a different location, or by installing a protective cover.
Damaged seals can lead to faulty operation. We strongly
recommend replacing controllers that have faulty seals.
22
Curtis 1204/1205 Manual, Rev. C
4 — MAINTENANCE & ADJUSTMENT
Adjustment
On some models, the plug braking current and acceleration rate settings
are adjustable. On these adjustable controllers, the adjustment pots are
located as shown in Figure 18.
Fig. 18 Adjustment
pots.
PLUG CURRENT ADJUST
(CW = higher plug current)
ACCELERATION RATE ADJUST
(CW = faster acceleration)
Use the following adjustment procedure. The keyswitch should be off
during adjustment.
1. Remove the socket head screw (1/8" Allen) for the adjustment
you want to make.
2. Adjust the internal potentiometer using a small insulated
screwdriver.
3. Replace the socket head screw and nylon seal washer. To prevent
stripping, do not over-tighten.
Curtis 1204/1205 Manual, Rev. C
23
4 — MAINTENANCE & ADJUSTMENT
POTBOX
Maintenance
Potbox maintenance is similar to controller maintenance: inspect for
integrity of connections and mounting, and clean (with a moist rag) as
required.
Adjustment
Curtis potboxes are factory set and rarely require user attention. To
test and adjust, connect an ohmmeter to the potbox wires and use this
procedure:
1. With the spring holding the lever arm against the return stop,
the resistance should be less than 50 ohms. Slowly move the
lever. If the resistance abruptly starts to increase when the lever
is 3 mm (1/8") from the stop (1.5 mm [1/16"] for potboxes
without the microswitch), no adjustment is needed.
2. If adjustment is required, loosen the screw holding the lever on
the pot shaft. Use a screwdriver to rotate the pot shaft slightly
with respect to the lever. Recheck the point at which the resistance
starts to increase and continue making adjustments until the
increase occurs at 3 mm (1/8") [at 1.5 mm (1/16") for potboxes
without the microswitch]. When adjustment is correct, tighten
the screw holding the lever on the pot shaft, then recheck to see
that this action did not disturb the adjustment. Make sure that
the lever is still seated down on the pot shaft below the slight
bevel on the end of the shaft.
24
3.
Check the resistance with the lever pushed all the way to the other
stop. It should be between 4500 and 5500 ohms. If it is outside
this range, the potbox is faulty and should be replaced.
4.
For potboxes equipped with a microswitch, check for correct
switch operation. Use an ohmmeter, or simply listen for the
slight click the switch makes. It should operate when the lever
is 1.5 mm (1/16") from the return stop. If it does not, adjust
by loosening the two screws holding the slotted microswitch
mounting plate to the stop spacers and moving the plate. Recheck the switch operating point after tightening the screws.
Curtis 1204/1205 Manual, Rev. C
5 — TROUBLESHOOTING & BENCH TESTING
5
TROUBLESHOOTING
AND BENCH TESTING
Some behaviors that may seem to suggest controller malfunction do not, in
fact, indicate a problem but rather are typical of normal operation. Before
undertaking the diagnostic tests, check to see whether your problem is addressed
in the first section, “Operational Notes.” The diagnostic tests are designed to
enable you to determine whether the trouble is in the controller or in some
other part of the motor control circuitry. The controllers themselves are
sealed and not field serviceable; contact your local Curtis service center
if the problem is in the controller. The diagnostic section provides enough
detail to enable you to track circuitry problems to their source and repair them.
Finally, the bench tests will allow you to confirm controller operation in a
simple, low-power test configuration. Bench testing is primarily intended for
checking out a number of controllers on a regular basis.
OPERATIONAL NOTES
Noise
Controller operation is normally silent. An exception is that a 1 kHz tone
may be heard during plug braking. This noise is normal and indicates that
plugging is taking place. The noise will stop when plug braking stops.
Inability of Vehicle to Plug Brake to a Stop on a Steep Ramp
If the vehicle is rolling backwards down a steep ramp in reverse and the
throttle is applied demanding forward drive, the controller will attempt to
plug the vehicle to a stop. If the ramp is so steep that the plugging current
setpoint is insufficient to stop the vehicle, it will continue to be braked
but will nevertheless roll down the ramp. If the mechanical brakes are
applied, and the vehicle is stopped, the full drive current will be available
when the throttle is applied and the vehicle will proceed up the ramp.
Sluggish Vehicle Behavior
Loss of power will be noticeable when the batteries become overly
discharged. This is a normal response to low battery voltage. Curtis
1204/1205 controllers are designed to protect against damage caused
by low batteries. On 24–36 volt controllers, for example, power to the
motor is cut back when the voltage goes below 16 volts. Refer to the
specifications (Appendix D) for other models.
Curtis 1204/1205 Manual, Rev. C
25
5 — TROUBLESHOOTING & BENCH TESTING
Hot Controller
If the controller gets hot, it does not necessarily indicate a serious problem.
Curtis 1204/1205 controllers protect themselves by reducing power to the
motor if their internal temperature exceeds 75°C (167°F). Power output
will be reduced for as long as the overheat condition remains, and full
power will return when the unit cools.
In typical applications, overheating will rarely be a problem. However, operation with oversized motors and vehicle overloading may cause
overheating, particularly if the controller is mounted so that heat cannot
be conducted away from its case or if other heat-generating devices are
nearby. If thermal cutback occurs often during normal operation, the
controller is probably undersized and should be replaced with a higher
current model.
Unintended Activation of HPD
Sudden applications of full throttle may activate the HPD feature, in
applications where the pedal microswitch is wired in line with KSI.
This happens if the pot is rotated well into its active stroke before the
microswitch can cause the controller to power up. Normal nonabusive
application of the throttle should not cause this action.
IN-VEHICLE DIAGNOSTIC TESTS
These tests require a general purpose volt ohmmeter; you can use either
a conventional “V-O-M” or an inexpensive digital voltmeter.
The troubleshooting chart (opposite) serves as a guide to the procedures
that follow. Before starting these tests, refer to the appropriate wiring
diagrams and make sure your controller is hooked up properly.
☞
C AU T I O N
26
Working on electric vehicles is potentially dangerous. You should
protect yourself while performing the diagnostic tests by jacking up
the vehicle to get the drive wheels off the ground, opening the battery
circuit before working on the motor control circuit, wearing safety
glasses, and using properly insulated tools (see page 2).
Curtis 1204/1205 Manual, Rev. C
5 — TROUBLESHOOTING & BENCH TESTING
Fig. 19 Guide to troubleshooting procedures. [To use this guide, refer to the specified
TEST
.]
PROCEDURES
1 Check for power to the controller
Check voltage at CONTROLLER B- and BATTERY B+ terminals.
1-A, B, C
if NO
It should read full voltage for system.
Bad, discharged, or miswired
batteries, or corroded
connections.
1-C
if YES
Check voltage at CONTROLLER B- and CONTROLLER B+ terminals.
if NO
It should read 1 to 5 volts less than full battery voltage.
TEST
TOO HIGH:
1-D
contactor is welded.
250 Ω resistor or
controller is defective.
1-D
TOO LOW:
D
2 Check for main contactor operation and KSI
Check voltage at contactor and at KSI terminal.
2-A, B, C
Contactor should read full rated voltage, and KSI must be above 8V.
if NO
Trace flow to locate
problem.
2-D
if YES
If voltage drop occurs,
contactor is defective.
2-E
if NO
Defective potbox, broken wires
to potbox, or improper
mechanical operation.
3-B
if NO
If lower than 1 MΩ, wiring or
potbox is defective.
3-C
if NO
Terminal area is probably
contaminated with acid or
dirt.
3-E, F
if YES
Check voltage across contactor power terminals.
2-D
There should be no measurable voltage drop.
TEST
3 Check potbox circuitry
(0–5kΩ throttles)
Check resistance at potbox wires while depressing pedal.
3-A
Resistance should be between 0–50 ohms with pedal UP, and
4500–5500 ohms with pedal DOWN.
if YES
Check for shorts between potbox wires and vehicle frame.
3-C
Resistance should be at least 1 megohm.
if YES
Check voltage at upper throttle input terminal on controller.
3-E
Voltage should be 3.6 to 4.2 volts with pedal UP,
and 9.1 to 10.3 volts with pedal DOWN.
TEST
4 Check for controller output
Check voltage output while depressing pedal (B+ to M-).
4-A, B, C
Voltage should be zero with pedal UP, and full battery voltage
with pedal DOWN.
if NO
Controller is defective.
4-C
if YES
Check current in controller’s M- (motor field) lead while
depressing pedal.
Current should be high, and motor should turn.
Curtis 1204/1205 Manual, Rev. C
4-D, E
if NO
If no current, look for open
circuit. If current is high but
motor won’t turn, check motor,
wiring & plug diode.
4-F, G, H, I
27
5 — TROUBLESHOOTING & BENCH TESTING
TEST
Check for power to the controller
1-A
Leave the keyswitch off for these tests.
1-B
Verify that battery (-) connects to the B- terminal of the controller.
Connect voltmeter (-) lead to this point.
1-C
Connect voltmeter (+) to the battery side of the main contactor.
Check for full battery voltage. If it is not there, the trouble is in the
battery pack, the cables to it, or the power fuse.
1-D
Connect the voltmeter (+) lead to the controller B+ terminal. You
should read a voltage 1 to 5 volts less than the full battery voltage.
If this voltage is zero or close to zero, the trouble is either a bad controller, a bad 250 Ω resistor across the contactor, or an incorrectly
connected cable between the contactor and the controller. Trace
the cable to make sure it is hooked up right. Remove and test the
250 Ω resistor with an ohmmeter. If these check out, the controller
is malfunctioning. If you see full battery voltage at this point, then
the contactor has welded and must be replaced.
TEST
28
1
2
Check for main contactor operation and KSI
2-A
Turn the key on, place the forward/reverse switch in forward or
reverse, and depress the footpedal until its microswitch operates.
(In these procedures, we assume the footpedal is equipped with the
recommended microswitch.)
2-B
This should cause the main contactor to operate with an audible
click. Connect the voltmeter across the contactor coil terminals. You
should see full battery voltage (minus the polarity diode drop).
2-C
The controller KSI terminal should also be getting full battery voltage. Verify this by connecting the voltmeter (-) to the controller’s Bterminal, and the voltmeter (+) to the controller’s KSI terminal.
2-D
If the contactor and KSI terminal are not getting voltage, that’s
the problem. Use the voltmeter to find out where it is not getting
through. Connect the voltmeter (-) to the controller’s B- terminal
and check the following points with the voltmeter (+) lead to trace
Curtis 1204/1205 Manual, Rev. C
5 — TROUBLESHOOTING & BENCH TESTING
the flow:
1. First, check both sides of the control wiring fuse.
2. Check both sides of the polarity protection diode
to make sure its polarity is correct.
3. Check both sides of the keyswitch.
3. Check both sides of the pedal microswitch.
4. Finally, check the contactor coil and controller KSI.
If the contactor coil and KSI are getting voltage, make sure the
contactor is really working by connecting the voltmeter across its
contacts (the big terminals). There should be no measurable voltage
drop. If you see a drop, the contactor is defective. (We assume the
recommended precharge resistor is in place.)
2-E
TEST
3 Check the potbox circuitry
The following procedure applies to the standard throttle input configuration
for these controllers, which is a nominal 5kΩ pot connected as a two-wire
rheostat (0 = full off, 5 kΩ = full on), and also to 5kΩ–0 configurations.
Some 1204/1205 controllers are sold with other input characteristics. If
your installation uses a controller with a throttle input other than 0–5kΩ
or 5kΩ–0, find out what its range is and use a procedure comparable to
the one below to make sure your pedal/potbox is working correctly.
3-A
With the keyswitch off, pull off the connectors going to the throttle
input of the controller. Connect an ohmmeter to the two wires going
to the potbox and measure the resistance as you move the pedal up
and down. The resistance at the limits should be within these ranges:
RESISTANCE (in ohms)
STANDARD
0–5kΩ POT
Pedal up:
Pedal down:
3-B
Curtis 1204/1205 Manual, Rev. C
5kΩ–0 POT
0 – 50
4500 – 5500
4500 – 5500
0 – 50
If these resistances are wrong, it is because the pot itself is faulty,
the wires to the pot are broken, or the pedal and its linkage are not
moving the potbox lever through its proper travel. Actuate the pedal
and verify that the potbox lever moves from contacting the pedal-up
29
5 — TROUBLESHOOTING & BENCH TESTING
stop to nearly contacting the pedal-down stop. If the mechanical
operation looks okay, replace the potbox.
3-C
While you have the potbox wires off the controller, use an ohmmeter
to check for shorts between these wires and the vehicle frame. You
should see a resistance of at least 1 megohm. If it is lower than that,
inspect the wiring for damaged insulation or contact with acid. If
necessary, replace the potbox.
3-D
Push the wires back on the controller terminals. It doesn’t matter
which wire goes on which terminal.
3-E
Inspect the terminal area of the controller closely. Occasionally a
buildup of dirt or acid residue of a conductive nature causes electrical leakage between the throttle input terminals and the B- or
M- terminals, leading to faulty controller operation. To check for
this problem, measure the voltage at the appropriate throttle input
terminal (upper for 0–5kΩ pots, lower for 5kΩ–0 pots), by connecting the voltmeter (-) lead to the controller’s B- terminal. The
keyswitch must be on and a direction selected for this test.
ACCELERATOR INPUT VOLTAGE (in volts)
STANDARD
0–5kΩ POT
5kΩ–0 POT
UPPER TERMINAL
LOWER TERMINAL
Pedal up:
3.8
4.3
Pedal down:
9.5
10.2
Compare your readings with these; if they are different by more
than a few tenths of a volt, contamination is probably the cause.
3-F
Carefully clean off the terminal area of the controller with a cotton
swab or clean rag moistened with water, and dry thoroughly.
Be sure to turn everything off
C AU T I O N
before cleaning.
Now test the controller to see if proper operation is restored. If so,
take steps to prevent this from happening again: dirt and water
must be kept from reaching the terminal area of the controller. If
the voltages are still out of range, the controller is at fault and should
be replaced.
☞
30
Curtis 1204/1205 Manual, Rev. C
5 — TROUBLESHOOTING & BENCH TESTING
TEST
4 Check for controller output
4-A
The first step is to measure the output drive voltage to the motor
at the controller’s M- terminal.
4-B
Connect the voltmeter (+) lead to the controller’s B+ terminal.
Connect the voltmeter (-) lead to the controller’s M- terminal.
4-C
Turn on the keyswitch with the forward/reverse switch in neutral,
and then select a direction and watch the voltmeter as you depress
the pedal. The voltmeter should read zero (or close to zero) before
you apply the pedal, and should read full battery voltage with the
pedal fully depressed. If it does not, the controller is defective and
must be replaced.
4-D
The next step is to measure the current in the controller’s M- lead.
If you have a means of measuring this high dc current, such as a
shunt/meter setup or a clamp-on dc ammeter, use it. If not, we recommend that you buy an inexpensive ammeter of the type that is
simply held against the wire being tested. These are readily available
at auto parts stores, and their accuracy is adequate for this test.
4-E
Turn on the keyswitch with the forward/reverse switch in neutral,
and then select a direction and watch the ammeter while depressing
the pedal.
4-F
If you see no current flowing in the M- lead, the problem is an
open circuit in the motor or the wiring between the motor and the
controller. Check the forward/reverse switch. If your vehicle uses
contactors for reversing, check to see that they are operating and
that their contacts are closing. If these are okay, check the motor
armature and field for opens.
4-G
If you do see a high current flowing in the M- lead, but the motor
does not turn, the problem is a short in the motor circuit, a miswired
motor, or a short in the controller’s internal plug diode. Test the
plug diode as follows:
1. Remove power by opening the battery circuit. Take
the cable off the controller’s A2 terminal.
Curtis 1204/1205 Manual, Rev. C
31
5 — TROUBLESHOOTING & BENCH TESTING
2. Use an ohmmeter to check the resistance between
the controller’s A2 and B+ terminals. You are testing
for the presence of a diode inside the controller, so
swap the two leads of the ohmmeter and look for a
low resistance one way and a much higher one the
other way. If your meter has a diode test function,
use it.
3. If you find the diode to be shorted, the controller
is defective.
4-H
Put the A2 cable back on the controller and reconnect the battery.
4-I
If the plug diode is okay, there is a short in the motor circuit. The
short could be in the forward/reverse switch, so look there first.
Because the resistance of the motor is so low, the motor must be
tested separately if it is suspected of having a shorted winding.
BENCH TESTING
First, before starting any bench testing, pick up the controller and shake
it. If anything rattles around inside, the unit should be returned.
☞
C AU T I O N
Protect yourself during bench testing. Wear safety glasses and use
insulated tools.
Equipment Needed
The simple setup shown in Figure 20 is required for testing these controllers on the bench. You will need:
1. a POWER SUPPLY with a voltage equal to the rating of the
controller you want to test. You can use either a string of batteries or a regulated line-operated power supply. Because only low
power tests will be described, a 10 amp fuse should be wired in
series with the batteries to protect both operator and controller
against accidental shorts. A battery charger alone should not be
used as a power supply, because without a battery load its output
voltage may exceed the rating of the controller.
2. an ACCELERATOR POTBOX. For controllers with the
standard input configuration (a 5 kΩ pot wired as a two-terminal rheostat), a Curtis potbox or any 5 kΩ pot will work fine.
32
Curtis 1204/1205 Manual, Rev. C
5 — TROUBLESHOOTING & BENCH TESTING
For controllers with other input options, use whatever kind of
potbox is used on the vehicle.
3. a POWER SWITCH to disconnect all power from the test
setup.
4. a MAIN CONTACTOR with a 250 ohm, 5 watt resistor
across its high-power contacts and a KEYSWITCH to turn it
on and off.
5. a TEST LOAD consisting of incandescent light bulbs wired
in series to get the same voltage as your power supply. (For
example, with a 36 volt battery, use three 12 volt bulbs.)
6. a general purpose VOLT OHMMETER or DIGITAL
VOLTMETER.
Fig. 20 Setup for bench testing.
5
RE W, 25
SIS 0 Ω
TO
R
POWER
SWITCH
KEYSWITCH
MAIN
CONTACTOR
E
10
US
AF
+
12 V
POWER SUPPLY
(to match your controller)
12 V
12 V
POTBOX
(to match your controller’s
throttle input)
TEST LOAD
(to match battery voltage)
Curtis 1204/1205 Manual, Rev. C
33
5 — TROUBLESHOOTING & BENCH TESTING
Bench Test Procedure
A. Hook up the controller as shown. Connect the voltmeter leads to the
controller’s B+ and B- terminals.
B. Turn on the power switch (not the keyswitch) and watch the voltmeter.
Its reading should build up slowly over several seconds to within a
couple of volts of full battery voltage. If this voltage does not come
up, the controller is bad.
C. Now turn on the keyswitch. The main contactor should turn on and
the voltage at the controller’s B+ and B- terminals should now equal
the full battery voltage. Move the potbox lever through its range. The
lamps should go smoothly from full off to full on with the pot.
D. If the controller has HPD, test this feature as follows:
1.
Turn off the keyswitch.
2.
Move the potbox lever about halfway.
3.
Turn the keyswitch switch on. Verify that the lamps
do not come on until the potbox lever is moved most
of the way toward OFF and then moved back up.
E. Test the controller’s potbox fault protection feature by pulling off
one of the potbox’s two connections to the controller’s throttle input
terminals while the lamps are on (potbox lever in the ON position).
The lamps should turn off. With the potbox lever still in the ON
position, reconnect the wire. The lamps should smoothly increase in
brightness to their previous level.
F.
34
Finally, remove the controller from the test setup and check its internal plug diode, as described in Troubleshooting Procedure 4-G .
Curtis 1204/1205 Manual, Rev. C
6 — GLOSSARY
6
GLOSSARY:
FEATURES and FUNCTIONS
Acceleration rate
A built-in acceleration rate circuit maintains a maximum rate of power
increase to the motor. If the throttle is applied full on at start-up, the
acceleration rate setting determines how quickly the controller output
increases. The standard setting is such that with the throttle full on, the
controller requires approximately one second to reach full output. This
feature contributes to smooth, gentle starts.
On some 1204/1205 models, the acceleration rate is adjustable via an
externally accessible trimpot. See Section 4 for adjustment instructions.
The deceleration rate is fixed, and cannot be adjusted.
Accelerator pot fault protection (runaway protection)
To prevent uncontrolled operation, these controllers shut off the motor
in the event of an open circuit fault in the accelerator potentiometer or
its wiring. The standard configuration is a two-wire pot ranging from 0
ohms for full off to 5000 ohms for full on; if the controller detects an
abnormally high accelerator input (more than about 1.5 times the normal
input resistance), it shuts off its output to the motor, thus preventing a
runaway. The controller returns to normal operation when the fault (e.g.,
broken potbox wiring, broken connectors) has been repaired.
Current limiting
Curtis controllers limit the motor current to a preset maximum. This
feature protects the controller from damage that might result if the current were limited only by motor demand.
In addition to protecting the controller, the current limit feature also
protects the rest of the system. By eliminating high current surges during vehicle acceleration, stress on the motor and batteries is reduced and
their efficiency and service life are improved. Similarly, there is less wear
and tear on the vehicle drivetrain, as well as on the ground on which the
vehicle rides (an important consideration with golf courses and tennis
courts, for example).
Current multiplication
During acceleration and during reduced speed operation, the Curtis
controller allows more current to flow into the motor than flows out of
Curtis 1204/1205 Manual, Rev. C
35
6 — GLOSSARY
the battery. The controller acts like a dc transformer, taking in low current
and high voltage (the full battery voltage) and putting out high current
and low voltage. The battery needs to supply only a fraction of the current
that would be required by a conventional controller (in which the battery
current and motor current are always equal). The current multiplication
feature gives vehicles using Curtis controllers dramatically greater driving
range per battery charge.
Environmental protection
Curtis 1204 and 1205 controllers are housed in rugged anodized aluminum extrusions that provide environmental protection. Controllers must
be kept clean and dry, however, to ensure long life.
High pedal disable (HPD)
[OPTIONAL FEATURE]
By preventing the vehicle from being turned on with the throttle applied, HPD ensures the vehicle starts smoothly and safely. If the operator attempts to start the vehicle when the throttle is already applied, the
controller (and the vehicle) will remain off. For the vehicle to start, the
controller must receive an input to KSI before receiving a throttle input.
In addition to providing routine smooth starts, HPD also protects against
accidental sudden starts if problems in the pedal linkage (e.g., bent parts,
broken return spring) give a throttle input signal to the controller even
with the pedal released.
The 1204 and 1205 controllers are available either with or without
the HPD feature.
KSI
KSI (Key Switch Input) provides power to the controller’s logic board
via both the keyswitch and the footpedal microswitch. For vehicles that
have no keyswitch, KSI is routed through the footpedal microswitch.
For non-vehicle applications (such as conveyor belts), KSI may simply
be tied to B+.
MOSFET
A MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is a
type of transistor characterized by its fast switching speeds and very low
losses.
Overtemperature
See Thermal protection.
36
Curtis 1204/1205 Manual, Rev. C
6 — GLOSSARY
Plug braking
The vehicle can be braked electrically by selecting the opposite direction
with the forward/reverse switch without releasing the throttle. When the
motor is reversed, the armature acts as a generator; the controller regulates
the current in the motor field winding to give an appropriate level of plug
braking torque. The vehicle brakes smoothly to a stop, then accelerates
in the other direction. (NOTE: The controller may be unable to provide
plug braking if the vehicle is moving too slowly for the motor to generate
the necessary plug braking current.)
The plug current limit is factory set to meet customer requirements.
On some 1204/1205 models, the plug current limit is adjustable via an
externally accessible trimpot. See Section 4 for adjustment instructions.
If plug braking is not desired, the vehicle can be wired so that
moving the forward/reverse switch through neutral causes the vehicle to
freewheel as long as the accelerator is applied. If the throttle is released
and reapplied, plug braking will then occur. To inhibit plug braking in
this way, your controller must have the optional HPD feature. Wiring
details are provided in Section 3.
A 1 kHz tone may be heard during plug braking.
PWM
PWM (Pulse Width Modulation), also called “chopping,” is a technique
that switches battery voltage to the motor on and off very quickly, thereby
controlling the speed of the motor. Curtis 1200 series controllers use high
frequency PWM—15 kHz—which permits silent, efficient operation.
PWM is described in more detail in Appendix B.
Smooth, stepless operation
Like all Curtis 1200 Series controllers, the 1204 and 1205 models allow
superior operator control of the vehicle’s drive motor speed. The amount
of current delivered to the motor is set by varying the “on” time (duty
cycle) of the controller’s power MOSFET transistors. This technique—
pulse width modulation—permits silent, stepless operation. Pulse width
modulation is described in Appendix B.
Thermal protection
Because of their efficiency and thermal design, Curtis controllers should
barely get warm in normal operation. Overheating can occur, however, if
the controller is undersized for its application or otherwise overloaded.
If the internal temperature of the controller exceeds 75°C (167°F), the
Curtis 1204/1205 Manual, Rev. C
37
6 — GLOSSARY
current limit decreases to approximately half its rated value. At the reduced performance level, the vehicle can be maneuvered out of the way
and parked.
Full current limit and performance return automatically after the
controller cools down. Although this action is not damaging to the controller, it does suggest a mismatch. If thermal cutback occurs often in
normal vehicle operation, the controller is probably undersized for the
application and a higher current model should be used.
The controller is similarly protected from undertemperature. Should its
internal temperature fall below -25°C (-13°F), the current limit decreases
to approximately half of the set current. When the controller warms up,
full current limit and performance return automatically.
Undertemperature
See Thermal protection.
Undervoltage protection
The control circuitry requires a minimum battery voltage to function
properly. The controller is therefore designed so its output is gradually
reduced if the battery voltage falls below a certain level. Cutback voltages for the various models are listed in the specifications (Appendix D).
Reducing the output to the motor allows the battery voltage to recover,
and an equilibrium is established in which the battery supplies as much
current as it can without falling below the cutback voltage.
38
Curtis 1204/1205 Manual, Rev. C
APPENDIX A: FUNCTIONAL DESCRIPTION
APPENDIX A
FUNCTIONAL DESCRIPTION
(SHADED AREA REPRESENTS CONTROLLER)
POWER
SECTION
LOGIC SECTION
B+
UNDER
VOLTAGE
DETECT
ARM
A2
SWITCH
KSI
PLUG
DETECT
A2
START-UP
TIMER
SHUT
DOWN
THROTTLE
INPUT
SCALING
POT
FAULT
THROTTLE
POT
M-
+
ACCELERATION
CIRCUIT
ACCELERATION
RATE ADJUST
LIMIT
INTEGRATOR
PULSE
WIDTH
MODULATOR
GATE
DRIVE
CURRENT
LIMIT
COMPARATORS
CURRENT
LIMIT
DISABLE
S2
+
MOSFETs
OSCILLATOR
FILTER
CAPACITORS
+14 VOLTS
TO ALL CIRCUITS
HIGH
PEDAL
DISABLE
THROTTLE
INPUT
S1
FIELD
KEYSWITCH
and
INTERLOCKS
A1
PLUG DIODE
FREEWHEEL
DIODE
+14V
REGULATOR
–
B-
CURRENT
LIMIT
REFERENCE
PLUG
CURRENT
ADJUST
CURRENT
LIMIT
ADJUST
(internal)
OVER
TEMP
TEMP
SENSE
UNDER
TEMP
Fig. A-1 Block diagram, Curtis 1204/1205 controllers.
The controllers consist of a POWER SECTION and a LOGIC SECTION.
POWER SECTION
An array of paralleled power metal oxide semiconductor field effect transistors (MOSFETs) switches
pulses of current from the battery to the motor. During the interval when the MOSFETs are off,
the motor current continues to flow in the freewheel diode, which is actually a number of paralleled
fast recovery rectifiers. An array of filter capacitors connected directly across the battery provides
the instantaneous current required by the power switching circuitry and in this way provides
battery ripple current filtering and voltage spike suppression. The plug diode provides a path for
armature current to flow during plug braking of series motors. In versions of these controllers for
Curtis 1204/1205 Manual, Rev. C
A-1
39
APPENDIX A: FUNCTIONAL DESCRIPTION
use with PM motors only, the plug diode and A2 terminal are omitted; however, the Functional
Description is written in terms of series motors.
LOGIC SECTION
B- is the ground return for all of the logic circuitry. For systems over 12 volts, the battery supply
is regulated down to 14 volts to power the logic circuitry. The output of the 14 volt regulator is
switched on and off (switch) by the keyswitch input (KSI) to power up the control circuitry when
the vehicle is in use and to power it down (shutdown) when the vehicle is not in use.
The speed control input (throttle input) is usually a 5000 ohm, two-wire pot, but other types
can be accommodated, so a flexible throttle input scaling circuit conditions the control input to
a standard level. This standardized throttle input goes to the acceleration circuit which limits the
rate at which the controller output can increase. The acceleration rate is set by a resistance, and is
adjustable via a user accessible trimpot (acceleration ramp adjust).
The output of the throttle input scaling also goes to a pot fault circuit which turns the controller
output off in the event of inputs (e.g., broken wires) which would otherwise cause a runaway. An
optional protective feature, high pedal disable (HPD), inhibits controller output if the controller is
turned on with the throttle applied. After an interval measured (start-up timer) from the moment
the KSI input is turned on, the HPD circuit checks the throttle position. If an applied throttle
condition is detected, controller output is held off until the throttle input is returned to zero and
then normal operation is allowed.
The control signal then goes to the limit integrator which reduces the controller output in response
to undervoltage or overcurrent. The time-averaged response of this circuit gives a stable limiting action. The undervoltage detector gives an output when the battery voltage is too low. The
reduction in output allows the battery voltage to recover and an equilibrium to be established at
a voltage high enough to allow the controller to function properly. The current limit function is
explained in more detail below.
The heart of the logic circuitry is the pulse width modulator in which the control input derived
from the previous stages is compared in magnitude to a 15 kHz sawtooth wave from the oscillator. The resulting pulse output can be smoothly varied between full off and full on. These pulses
become the input to the controller’s main power MOSFET switch via a gate drive circuit that
provides the high pulse currents needed to turn the power MOSFETs on and off (see Fig. B-1).
The shape of the sawtooth wave may be altered so that most of the pulse width change occurs in
the earlier or in the latter part of the control input range, giving more sensitive throttle response
at high or at low speeds.
Current limiting is done by sensing the voltage drop across the main power MOSFET switch when
it is on. This voltage is compared (current limit comparators) with a current limit reference; when
it exceeds the reference, an overcurrent signal acts on the limit integrator to reduce the controller
40
A-2
Curtis 1204/1205 Manual, Rev. C
APPENDIX A: FUNCTIONAL DESCRIPTION
output and thus hold the current at the limit. Because the voltage across the power MOSFET
switch is high when it is off, the current limit comparison is inhibited during the off interval by
the current limit disable circuit. The current limit is set as follows:
1.
During manufacture, the current limit is set by an internal trimpot (current
limit adjust) to the model’s nominal rating.
2.
During operation at extreme high or low temperatures, current limit is reduced to protect the controller from damage. From a thermal sensor (temp
sense) on the heatsink, signals are produced to cut back the current limit
at temperatures above 75°C or below -25°C (overtemp, undertemp).
3.
During plug braking operation, the current limit is reduced to give an
appropriate motor braking torque. The plug braking current is set during
manufacture; it is also user-adjustable by a trimpot (plug current adjust).
The plug current limit reference is derived from the current limit reference.
The transition to the plug braking mode is detected (plug detect) by monitoring the voltage across
the plug diode. When this diode becomes forward biased, it indicates that the motor field has been
reversed and the controller has gone into plug mode. The current limit is reduced as described,
and the frequency of the oscillator is reduced from 15 kHz to 1 kHz, to allow finer control of
the controller output while plugging. During plug braking operation, the acceleration circuit is
reset to a low level so that when drive operation resumes, the controller will go through a normal
acceleration ramp. When the motor has come to a stop, the plug diode will again become reverse
biased and the controller will revert to normal drive operation.
Curtis 1204/1205 Manual, Rev. C
A-3
41
APPENDIX B: PULSE WIDTH MODULATION
APPENDIX B
PULSE WIDTH MODULATION
(SHADED AREA REPRESENTS CONTROLLER)
FREEWHEEL
DIODE
ARM
FILTER
CAPS
MOTOR
+
PLUG
DIODE
FIELD
BATTERY
+
–
CURRENT PATH DURING
TRANSISTOR ON TIME
CURRENT PATH DURING
POWER
MOSFETS
MOTOR CURRENT
CONTROL
CIRCUITRY
THROTTLE
POTBOX
TRANSISTOR OFF TIME
TIME
Fig. B-1 Pulse width modulation.
A high power semiconductor switch, consisting of an array of parallel power MOSFET transistors,
controls the current in the motor windings. The transistors are connected in series with the battery
and the motor. The transistors are turned on and off 15,000 times per second by the controller
circuitry, while the ratio of the on/off times is varied in response to the input demanded by the
accelerator.
When the transistors are on, the current through the motor builds up, storing energy in the motor’s
magnetic field. When the transistors are off, the stored energy causes the motor current to continue
to flow through the freewheel diode. The control current ramps up and down as the switch turns
on and off. Average current, which determines motor torque, is controlled by the ratio of on/off
times. Smooth, stepless control of the power delivered to the motor is achieved with almost no
power loss in the control components.
42
B-1
Curtis 1204/1205 Manual, Rev. C
APPENDIX C: WEEE / RoHS
APPENDIX C
CURTIS WEEE / RoHS STATEMENT, MARCH 2009
WEEE
The Directive 2002/96/EC on Waste Electrical and Electronic Equipment (WEEE) was adopted
by the European Council and Parliament and the Council of the European Union on January 27,
2003. The aim of the directive was to improve the collection and recycling of WEEE throughout
the EU, and to reduce the level of non-recycled waste. The directive was implemented into law by
many EU member states during 2005 and 2006. This document provides a general description of
Curtis’s approach to meeting the requirements of the WEEE legislation.
Note that the directive gave some flexibility to the member states in implementing their individual WEEE regulations, leading to the definition of varying implementation requirements by
country. These requirements may involve considerations beyond those reflected in this document.
This statement is not intended and shall not be interpreted or construed to be legal advice or to
be legally binding on Curtis or any third party.
Commitment
Curtis is committed to a safe and healthy environment and has been working diligently to ensure
its compliance with WEEE legislation. Curtis will comply with WEEE legislation by:
• Designing its equipment with consideration to future dismantling, recovery and
recycling requirements;
• Marking its products that fall within the scope of the directive with the required
symbol and informing users of their obligation;
• To separate WEEE from general waste and dispose of it through the provided recycling systems;
• Reporting information as required by each member state;
• Facilitating the collection, recycling and disposal of WEEE from private households
and other than private households (businesses) as defined by the applicable member
state regulation;
• Providing information to treatment centres according to the requirements defined
in the local regulation.
WEEE symbol on Curtis products
The requirement to mark equipment with the WEEE symbol (the crossed-out wheeled
bin) went into effect as of August 13, 2005. As of this date, Curtis Instruments began
the process of marking all products that fall within scope of this directive with the
WEEE symbol, as shown opposite.
Curtis 1204/1205 Manual, Rev. C
C-1
43
APPENDIX C: WEEE / RoHS
Obligations for buyers of electrical and electronic equipment
As of 13 August 2005, in each EU member state where the WEEE directive has been implemented,
disposal of EEE waste other than in accordance with the scheme is prohibited. Generally, the schemes
require collection and recycling of a broad range of EEE products. Certain Curtis products fall
within the scope of the directive and the implemented member state regulations. Affected Curtis
products that have reached end-of-life must not be disposed as general waste, but instead, put into
the collection and recycling system provided in the relevant jurisdiction.
RoHS
For several years now, Curtis has been implementing a rigorous program with the aim of achieving full compliance with the Restrictions on the use of Hazardous Substances (RoHS) Directive,
2002/95/EC.
Curtis has taken all available steps to eliminate the use of the six restricted hazardous substances
listed in the directive wherever possible. As a result of the Curtis RoHS program, many of our
instrumentation product lines are now fully RoHS compliant.
However, Curtis’s electronic motor speed controller products are safety-critical devices,
switching very large currents and designed for use in extreme environmental conditions. For these
product lines, we have successfully eliminated five out of the six restricted hazardous substances.
The single remaining issue preventing full RoHS compliance is the unsuitability of the lead-free
solders available to date, due to the well-documented issues such as tin whiskers, and premature
failure (compared with leaded solder) due to shock, vibration, and thermal cycling.
Curtis is closely monitoring all RoHS developments globally, and in particular is following the
automotive industry’s attempts to introduce lead-free solder as a result of the End of Life Vehicle
(ELV) Directive, 2003/53/EC. To date, the automotive industry has rejected all lead-free solder
pastes due to a significant reduction in reliability compared to leaded soldering.
Curtis firmly believes that the operating environments, safety requirements, and reliability
levels required of automotive electronics are directly analogous to that of our speed controller
products. As such, Curtis will not be switching to a lead-free solder process until lead-free solder
pastes and techniques are available that meet the requirements of the RoHS study groups and
ELV Automotive Industry bodies. That is, when all known issues, including that of tin whiskers,
are satisfactorily resolved.
At this moment in time, all Curtis motor speed controllers used on industrial vehicle applications
are also regarded as exempt under EEE category 9 of the RoHS directive 2002/95/EC. This means
there is no requirement at this time for Curtis control systems used on such equipment to comply
with the directive. Curtis will work closely with all key customers to ensure that whenever possible,
we are in a position to continue the supply of products should these exemptions expire.
44
C-2
Curtis 1204/1205 Manual, Rev. C
APPENDIX D: SPECIFICATIONS
APPENDIX D
SPECIFICATIONS
NOMINAL INPUT VOLTAGE
12V, 24–36V, and 36–48V
PWM OPERATING FREQUENCY
15 kHz
STANDBY CURRENT
less than 20 mA
STANDARD THROTTLE INPUT
5 kΩ ±10% (others available)
WEIGHT
1204: 1.8 kg (4 lbs)
DIMENSIONS
1204: 146mm×170mm×70mm (5.75”×6.75"×2.8”)
1205: 146mm×222mm×70mm (5.75”×8.75"×2.8”)
1205: 2.7 kg (6 lbs)
NOMINAL
BATTERY
VOLTAGE
CURRENT
LIMIT
2 MIN
RATING
5 MIN
RATING
1 HOUR
RATING
VOLTAGE
DROP
@ 100 AMPS
UNDERVOLTAGE
CUTBACK
(volts)
(amps)
(amps)
(amps)
(amps)
(volts)
(volts)
24–36
24–36
24–36
24–36
275
175
275
175
275
175
275
175
200
130
200
130
125
75
125
75
0.35
0.50
0.35
0.50
16
16
16
16
-4XX
-5XX
36–48
36–48
275
175
275
175
200
130
125
75
0.35
0.50
21
21
-6XX
-7XX
12
12
275
175
275
175
200
130
125
75
0.35
0.50
9
9
24–36
36–48
12
400
350
400
400
350
400
275
250
275
175
150
175
0.25
0.30
0.25
16
21
9
MODEL
NUMBER
1204-0XX
-1XX
-2XX †
-3XX †
1205-1XX
-2XX
-3XX
† Models for use with permanent magnet motors (no A2 bus bar provided).
Curtis 1204/1205 Manual, Rev. C
45
D-1