PDF Service Manual Clark Forklift PWC 30 PWT 7 - 2 MB
Keep your Clark PWC 30 and PWT 7 forklifts running smoothly with this detailed service manual.
It contains comprehensive procedures for maintenance, troubleshooting, and major repairs.
Technicians will find this guide invaluable for diagnostics and disassembly of key components.
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--- Page 1 ---
SM-614
PWC 30, PWT 7
Service Manual
--- Page 3 ---
GENERAL INFORMATION
RECORD KEEPING
Model & Serial No. Stock No.
Date Placed in Service
GI 3-2
--- Page 4 ---
GENERAL INFORMATION
PWC MAINTENANCE SCHEDULE
Period Time Function
Daily
Check water level in battery.
Check oil level transmission.
Check all wheels and tires. Remove any and all tape,
plastic and material.
Check operation of truck steering and speed change
including all warning and safety devices (if equipped),
horn, speed limit switch, lift limit switches, lights.
Ensure that unit lifts and lowers properly.
Check brake operation and stopping distance (approx.
the length of the truck including forks, unloaded).
Check oil levels and insure unit has been greased.
Check hydraulic tank with load carrying device (forks)
fully lowered. Check for and correct any leaks.
Weekly 100 Hours
Check speed of truck and plugging distance (PMCBCR
only).
* * Check brake linkage, adjust as necessary. Lubricate pivot
points, see lubrication chart (located in Service
Information Section).
Check entire truck for loose items, power and control
wiring, linkage, nuts and bolts.
Clean battery terminals of corrosion. Check electrolyte
level. Inspect plug and battery cables.
Clean and inspect motor brushes. Use only low pressure
air or vacuum.
Check all hydraulic hoses and fittings for wear or leaks,
repair as required.
Inspect contact tips.
Clean any and all dirt or corrosion from terminal area of
PMC Controller units.
30 Days 200 Hours
Check steerhead bearing for wear.
Lubricate entire truck see lubrication chart (located in
Service Information Section, for type and points).
Check safety devices, horn, alarms (if equipped), lift
limit switch and slow speed adjustment. Repair or adjust
before truck goes back into operation.
l/98 GI4-10
--- Page 5 ---
GENERAL INFORiMATION
BATTERY CARE AND SERVICE
The Chemical Reaction (cont’d.)
During cell discharge, Lead Peroxide and Sponge Lead combine with sulfuric acid to form Lead
Sulfate (Pb Sod) on both plates (See Fig. 3). This action decreased cell voltage as the two electrodes
approach being of the same chemical composition (Lead Sulfate). As the sulfuric acid is removed
from the electrolyte solution the specific gravity of the electrolyte decreased and approaches the
specific gravity of water (See Fig. 4). The discharged cell will have a voltage potential of approxi-
mately 1.75 volts. LL53nUNWWun
I
+
I
When charging current is applied to a discharged cell (as shown if figure 5) the Lead Sulfate is broken
up, the active materials are restored to their respective plates and the electrolyte again becomes a
sulfuric acid solution. Cell voltage rises as the two elements become increasingly different in compo-
sition. The specific gravity of the electrolyte increases as more and more is formed.
Once again we have a fully charged cell, the positive electrode is Lead Peroxide, the negative elec-
trode is Sponge Lead and the electrolyte is a sulfuric acid solution.
l/98 GI 5-4
--- Page 6 ---
GENERAL INFORiKATION
BATTERY CONTROLLER
What The Gage Measures (cont’d.)
When the truck does heavy work consisting of a lot of lifling and little driving, the gage will not
permit as much total energy to be removed from the battery as when the truck does light work.
This will be evidenced in two ways:
1. Lockout will occur sooner.
2. The specific gravity of the battery at lockout will be higher.
Only when the occurrence of lockout interferes with the work schedule should adjustments be made.
This should be done in consolation with the truck supplier and the battery supplier to insure the
equipment is not damaged and warranties invalidated.
Precise details of when to adjust and how to adjust are given later.
Troubleshooting
Equipment Needed:
Digital Voltmeter with better than .5% accuracy
Curtis 1142 2048 tester
1141 FasTesT Accessory (Optional - speeds up discharge testing from 30 minutes to I
minute.
Description and hookup of the 1141 and 1142 are on the attached data sheet.
Symptom: Gage does not reset to full with a freshly charged battery.
Check battery voltages across controller terminals 1 and 8. No current should be flowing from the
battery at the time. If voltage is greater than 25.3 volts for 24 volt butteries or 38 volts for 36 volt
batteries, gage should rest.
Before replacing controller, check that reset pot is at B. If not, set to B, disconnect the battery for 15
seconds and reconnect. If reset is not, achieved replace controller.
If battery voltage is less than the values above, the following problems can exist:
Battery needs to have sulfuric acid added to it.
: Insufficient time on the charger to bring the battery up.
Charger malfunctioning.
: Battery has shorted cells.
While corrective action is being taken, the battery still can be used but with reduced capacity and
shorter work time on the floor.
GI 6-5 l/98
--- Page 7 ---
GENERAL INFORMATION
PAINT & DECAL
PWC
ITEM NO. PART NO. DESCRIPTION on.
38693-900 Standard Paint & Decal
38693-901 Fixed Steerhead Paint & Decal
38693-902 Tilt Steerhead Paint & Decal
1 39250-004 Decal, 24V Only 1
5 39065-005 Non-Skid Matting 2
6 97836IOKOO-Fl Decal, Warning (Pinch Point) 2
7 39250-006 Decal, Clark 1
11 27607-00 1 Rivet (use additional qty. of 6 on Fixed Steerhead) 4
12 * Serial Number & Capacity Plate 1
13 39241-000 Decal, Warning (Operator) 1
14 27763-O11 Anti-Fatigue Matting 1
15 39250-001 Decal, USA Flag 1 1
16 15817-013 Sponge Rubber Knee Pad 1
17 15817-011 Sponge Rubber Knee Pad 1
18 39245-000 Decal, Warning (Do Not Tilt, use on Tilt Steerhead) 1
19 39244-000 Decal, Warning (Apply Parking, use on Tilt Steerhead) 1
20 39247-000 Decal, Warning (Caution, use on Tilt Steerhead) 1
21 39250-003 Clark Logo Plate 1
22 12485-092 Key Switch Nameplate (use on Fixed Steerhead) 1
23 11434-015 Reverse Switch Nameplate (use on Fixed Steerhead) 1
24 11434-038 Horn Switch Nameplate (use on Fixed Steerhead) 1
25 39243-000 Decal, Caution Polartiy 1
26 39409-000 Decal, Warning (Battery Gate) 4
27 39430-000 Decal, Control Function 1
28 39801-000 Rubber Strip 1
29 6183-000 Nameplate, Lift/Lower (use on Fixed Steerhead) 1
31 39323-000 Nameplate, UL - ES Rated Trucks (use additional qty. of 4 of Item # 11) 1
32 96917~L4000-Fl Decal, ES Rated $ucks 2
-- * Black Paint AR
-_ * Green Paint AR
*Consult Factory with Model and Serial Number.
1198
--- Page 8 ---
BASIC TEST (TOOLS) EQUIPMENT IN TROUBLESHOOTING
On the following pages, proper use of the Simpson VOM and Handyman Component Tester is pre-
sented. Proper use of the Electric Vehicle System Analyzer has been presented at the end of each
section on component identification.
CLARK stresses that the minimum test equipment to properly troubleshoot an Electric Forklift would
consist of
1) A high quality Volt-OHM-Current meter as the Simpson VOM or Fluke Multimeter.
2) A Handyman Component Tester.
3) AMP Meter or Stunt.
EC 2-4
--- Page 9 ---
ELECTRIC CONTROL
ROTARY SWITCH
To turn the meter on, turn the rotary switch from the
OFF position. The meter pexforms a selftest, then
starts taking readings.
Function R&Lead Descrhionhmt Limits
.zt
V- vR4 Volts AC-75OV ac
V --_-__ W-i- Volts DC -lOOOVdc
mVZ VsZ-d- Millivolt-5OOVdc or rms ac
R vR4 Ohms resistance-500V dc or rms ac
4 2))) vR4 ContinuiQ with beeper-500V dc or rms ac
A- 1OA Amps AC-1OMOOV (20A < 30 sex)
A __-____
3oomA Amps DC -320 lnivzov
EC 2-14
--- Page 10 ---
ELECTRTC CONTROL
HANDYMAN COMPONENT TESTER
SCR BLOCKING VOLTAGE
(LEAKAGE) TEST DIODE REV.
DEVICE UNCERTEST
VOM-OPTIONAL
r------- - IMPORTANT -
1
l SOME STUD TYPE DIODES
HAVBTHElR ANODE AND
Q
i CATHODE REVERSED.
SUFFIX 2” IN PART NO.
I
l
f
055’
I 0"'
PRESSLEAKTESTBUTION
VOM MBASURES TEST
VOLUME
LED INDICATOR SHOWS
FUNCTIONSELECTORIN FUNCTION LEAKAGE IN EKE% OF 1 MA
“LEAKAGE” TEST POSlTiON SELECTION
VOM MEASURES
“ON” VOLTAGE
- IMPORTANT -
SOME STUD TYPE DIODES
HAVETHEIRANODEAND
CATHODE REVERSED.
SUFFIX “R” IN PART NO.
“CONXNUTY” LAMP SHOWS
PROPERFIRING AND HOLDING
25VDCRANGEGQODSCR’S OF SCR
WILL RANGE BEXWEEN 0.6 8c
l.!iV PRESSGATBTBSTBUTIONSTO
FIRESCRANDCHECK
FUNCTIONSELECTOR IN
“CON’nNwW’ TEST POSITION TESTALLSCR’SUSING”LO”
GATE TESTBUTIONS
!3WlTCHFUNCXON SELECTOR
MOMENTARILY TO OFF/PEAK SOMELARGER SCR’S ONLY MAY
READINGANDTHENBACKTO REQlJlREUSlNG“HI”GATElEST
REPEATTEST BUTIQN’I-OFIRE
‘EC 2-24
--- Page 11 ---
ELECTMC CONTROL
BASIC OPERATION FOR PWT
RESISTOR CONTROL CONTACTOR
B.D.I. Speed Control Option
One of the most common options is to use a Battery Discharge Interrupt to cut the speed of the unit
when the battery voltage is lower than 80%. The simple diagram below shows how a battery dis-
charge interrupt meter can be used to cut out the battery negative (-) lead to the speed time delay.
This then cuts both 2nd and 3rd speed from turning on. Please note that this is only the most com-
mon type of speed interrupt and you should always refer to your units Parts Manual for the correct
assembly used.
FUSE TlME DELAY
BATTERY TO‘am 1SPEED
TO 3RD SPEED
l/98 EC 3-4
--- Page 12 ---
PARTSPAGE
ALWAYS SPECLFY MODEL AhKI SERL4L NUMBER MEA’ ORDERlNG PARTS
PWT 7 24V POWER WIRING 3 SPEED RESISTOR,
W/EV-1 FWDJREV. CONTACTORS & TILT OR FIXED STEERHEAD
lTEM NO, PART NO, DESCRIPTION
1 8268-000 SB-2 Connector 1
2 7028-008 l/4-20 x 1.50” Lg. Hex Head Bolt 2
3 7000-009 l/4 Lock Washer 12
4 7001-001 l/4-20 Hex Nut 2
5 39069-00 1 Standoff Resistor 6
6 39080-005 Resistor (Use Qty. 2 on PWT 7) 1
7 7162-005 l/4 Flat Washer 10
8 7028-004 l/4-20 x .75” Lg. Hex Head Bolt 2
9 7028-005 l/4-20 x .88” Lg. Hex Head Bolt 6
14 27732-03 1 Buss Bar 1
15 29000262-000 200 Amp Fuse 1
23 7028-002 l/4-20 x .50” Lg. Hex Head Bolt 2
50 7000-010 S/l6 Lock Washer 4
52 39080-00 1 Resistor (Used Only on PWT 7) (Fast Resistor) 1
9510 3-10 PWT 7-102I-5A~ZS40&120 & I21
--- Page 13 ---
PARTSPAGE
ALWA YS SPECIFY MODEL AND SERUL NUMBER WHEN ORDERING PARTS
PWT 7 24V POWER WIRING 3 SPEED RESISTOR,
W/EV-1 FWDJREV. CONTACTORS & TILT OR FIXED STEERHEAD
ITEM NO, PART NO. DESCRIPTION on.
1 8268-000 SB-2 Connector 1
2 7028-008 l/4-20 x 1.50” Lg. Hex Head Bolt 2
3 7000-009 l/4 Lock Washer 12
4 7001-001 l/4-20 Hex Nut 2
5 39069-001 Standoff Resistor 6
6 39080-005 Resistor (use Qty. 2 on PWT 7) 1
7 7162-005 l/4 Flat Washer 10
8 7028-004 l/4-20 x .75” Lg. Hex Head Bolt 2
9 7028-005 l/4-20 x .88” Lg. Hex Head Bolt 6
14 27732-03 1 Buss Bar 1
15 29000262-000 200 Amp Fuse 1
23 1 7028-002 l/4-20 x .50” Lg. Hex Head Bolt 2
50 7000-010 5116 Lock Washer 4
52 39080-001 Resistor (Used Only on PWT 7) (Fast Resistor) 1
9609 3-10 PWT 7-l OZl-6/25408-120 & 121
--- Page 14 ---
ELECTRlC CONTROL
SERVICE GUIDE
FOR PMC CONTROL (1204/1205/1209B)
This manual covers all current Curtis PMC units (1204/1205/l 209).
SECTION 1 FEATURES OF CURTIS PMC SERIES TRANSISTORIZED MOTOR
CONTROLLERS
1.1 Smooth Stepless Operation
The Curtis PMC 1204/l 205/l 209 series of transistorized motor speed controllers give electric ve-
hicles new and improved driving characteristics by allowing superior operator control of the vehicle’s
drive motor speed. This is possible through the use of electronic control techniques by which the
power delivered to the motor can be smoothly varied from fully off to full on. There are no speed
steps or increments.
A high power semiconductor switch, consisting of an array of paralleled power MOSFET transistors,
controls the current in the motor windings. As sown in figure below, the transistors are connected in
series with the battery and the motor. The transistors are turned on and off at the rate of 15,000
timers per second by the control circuitry, while the ratio of the on and off times is varied in response
to the input demanded by the throttle. This technique is called pulse width modulation. When the
transistors are on, the current through the motor builds up, storing energy in the motor’s magnetic
field. When the transistors turn off, this stored energy causes the motor current to continue to flow
through the freewheel diode. As shown in figure below, the motor current ramps up and down as the
switch turns on and off, the average current (which determines the motor torque) being controlled by
the ratio of the on and off times. In this way, smooth, stepless control <the power delivered to the
motor is achieved with the very low power loss in the control components.
v---w,
CONTROLLER
~_~_--~---
+-L
;=,
I I
EATTERG
7 1 +
I :-
1 FILTER
CAPS
-L
I
=
- I
I
. COWRDL
I
I
ACCELERATOR
POT
YOTOR CURRENT
- - - - - CURRENT WTW DURING
TRANSSTDR ‘ON’ TIME
1
0000000 CURRNPAT~DUllNC
fRANSlST03( lOFF’flYE
I i I
EC 4-3 l/98
--- Page 15 ---
ELECTRIC CONTROL
SERVICE GUIDE
FOR PMC CONTROL (1204/1205/1209B)
SECTION 4 TROUBLESHOOTING
4.1 Introduction
The following procedures are intended to help users of Curtis PMC 1204/1205/1209 controllers
diagnose problems in the field. The controllers themselves are sealed and thus not field serviceable,
so the intent is to enable the user to determine if the trouble is in the controller or some other part of
the motor control circuitry. This guide is detailed enough to enable users to track down these other
problems to their source and repair them.
CAUTION:
IT IS IMPORTANT THAT THE TEST BE DONE IN THE ORDER THAT THEY
ARE WRITTEN; IF NOT, THE CONCLUSIONS REACHED MAY NOT BE
VALID.
The controllers have features designed to protect against damage caused by low batteries. The power
to the motor is cut back when the battery voltage goes below approximately 16 volts (for 24-36 volt
controllers). The loss of power felt when the batteries become this far discharged is normal. Simi-
larly, the controllers are protected against damage from overheating by reducing the power to the
motor if the internal temperature exceeds 165°F. In typical applications of these units, overheating
will very rarely be a problem. Operation with oversized motors and/or vehicle overloading may cause
overheating, particularly if the controller is mounted so that heat cannot be conducted away from its
case. Power output will be reduced for as long as the overhead condition remains; full power will
return when the unit cools.
4.2 Symptoms and Cures
Some of these “symptoms” do not indicate a problem but rather are typical of normal operation. The
1 kHz tone heard during plug braking and the inability of the vehicle to plug brake to a stop on a
steep ramp, for example, are not indicative of controller malfunctions.
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. A 1 kHz tone may also be heard if the controller overheats. The controller shifts
frequency during over-temperature from its normal 15 kHz to 1 kHz, providing an audible tone to
alert the operator to the over-temperature condition.
EC 4-13 l/98
--- Page 16 ---
ELECTRIC CONTROL
BASIC OPERATION FOR
PWT CURTIS PMC
Battery Discharge Speed Interrupt
This operation uses either Curtis 933/3 or BDI with Lift Interrupt to put the unit into creep speed
when the battery becomes discharged below allowable voltage levels.
In this system the battery interrupt is connected to a relay. This relay is connected to the acceleration
pots. When the battery becomes to low, the relay bypasses the main acceleration system to a third
walkie speed pot, which is adjustable to a creep speed of approximately 1.5 mph. The relay is
mounted by the BDI itself and the pot is mounted in the lower right comer of the contactor panel (see
figure below).
PLATFORM
HI SPEED n
l/98 EC 5-4
--- Page 17 ---
ELECTRlC CONTROL
TROUBLESHOOTING
PWC CURTIS PMC CONTROL
NO TRAVEL - FORWARD dz REVERSE CONTACTORS ARE CLOSING
a WARNING:
Follow all warnings on Page EC 6-5.
Plug in battery, close start
switch, foward contactor
should close. Check fof
battery wltage on truck
side of power fuse, wire
#21.
YES
t
Check battery Recharge or
Does UJttage
No _ underload . No ) replace
stay level? test. battery.
,I , YES
Check for wltage
atB+onPMC
NC
controller, wire Repair wire
Use Setice Tip
#21. * #21 to fuse.
in PMC Venice
* ) Guide on Page
EC 4-15.
YES
w
v Motor &es not Motor runs Q
run. full speed.
Mow VOM Check forbattery -
negatiw (-), test YES wItage contml
lead to B- terminal ) terminal #l, wire
on PMC controller #lO on PMC YES
shwld still mad. contrdler.
No
No
v
Check for battery
u&age on terminal
strip position #lo.
Replace tie #l0 between
l/98 EC 6-6
--- Page 19 ---
ELECTRIC CONTROL
EV-100 CONTACTOR AND MAINTENANCE
Component Replacement
Contactor (Pump, 1A) 39186-001,010,011
Contact Tip Replacement (See Page EC 7-8 of this Section)
1. Remove nut (Item 1) from armature, Lift washer, spring retainer, spring and spring guide
washer (Item 2,3,4,5) from armature.
2. Lift movable contact (Item 6) from armature. Install replacement contact.
3. Assemble spring guide washer, spring & spring retainer and washer on armature.
4. Install nut on armature and tighten between 14- 18 inch-pounds (torque) (1.6-2.0 Newton
meters.
5. Remove four (4) long screws (Item 7) and remove the stationary tip clamps (Item 9) from
contactor assembly.
6. Remove stationary contacts (Items 11 & 12).
7. Install replacement contacts and secure in place with stationary tip clamps. Tighten four
screws in one turn increments using a diagonal pattern. Tighten screw between 14-18 inch-
pounds (torque) (1.6-2.0 Newton meters).
coils
1. Remove four (4) long screws (Item 7) and stationary tip clamps (Item 0.
2. Remove stationary contacts.
3. Lift stationary tip carrier (Item 24) with the armature assembly (Item 26) from the contactor
assembly.
4. Remove magnet frame (Item 28).
5. Lift coil (Item 29) from post on base plate (Item 30). Note position of coil terminals in
relation to base plate for assembly.
6. Position replacement coil on base plate, as noted in disassembly, and locate projections on
base plate in indentations of coil.
7. Position magnet frame over coil and locate projections on magnet frame in indentation of
coil.
8. Make certain the small end of spiral spring (Item 27) is formed over small diameter of
plunger (Item 26). Assemble armature assembly and stationary tip carrier on top of magnet
frame (as shown below).
l/98 EC 7-8
--- Page 20 ---
POWER WIRING FOR PWT 7 12 & 24V CURTIS PMC CONTROL
W/TILT OR FIXED STEERHEAD
ex”
2 13 P24
2 8268-000 SB-2 Cmmector
13 7028-008 M-20 x 1SO” Lg. Hex Head Bolt
23 7000-009 l/4 Lock Washer
24 7001-001 M-20 Hex Nut
26 7000-010 S/l6 Lock Washer
PWT 7.1071-5/25408-124 & 127
--- Page 21 ---
PARTSPAGE
ALWAYS SPECIFY MODEL AND SERLAL NUMBER K’TEN ORDERLNG PARTS
PLATFORM HI-SPEED SWITCH FOR PWT 7 CURTIS PMC CONTROL
For Final Assembly Breakdown See Parts Page 1017-2 Located in Final Assembly Section.
-
FLOOR MATTING
MAlTlNG PLATE
FLOOR PLATE
SUPPLIED WITH
- ACTUATOR
-.
-. -SEE CONTROL WIRING
DIAGRAM FOR WIRE NUMBERS
-
ITEM NO. PART NO. DESCRIPTION
1 7660-093 spring
2 27350-025 Switch, Plunger Pin
3 27350-026 Actuator Plunger
PWT 7-1071~6/25408-128
--- Page 22 ---
PARTSPAGE
ALWAYS SPECIFY MODEL AND SERUL NUMBER WHEN ORDERING PARTS
CONTROLWIRINGFORPWC30/4024VCURTISPMCCONTROLLER
WITHTEEHANDLEINTERMEDIATESECTION
ITEM NO, PART NO, DECRIPTION SEL
1 38900-025 Coritactor Panel (See Pages 5-12 and 6-12) 1
3 3 8460-000 Potentiometer Bracket 1
4 27140-002 Potentiometer, Slow Speed 1
5 29000465-000 Brake Switch 1
10 7910-001 Insulated Standoff 5’
12 38905-012 Steerhead Harness 1
30 7001-005 3/8- 16 Hex Nut 2
31 7000-O 11 318 Lock Washer 2
33 7162-009 l/2 Flat Washer 2
35 7099-O 14 ##6-32 x 1.25” Lg. Round Head Screw 2
36 7002-013 ##6-32 Hex Nut 2
37 7162-001 #6 Flat Washer 2
38 7000-005 ##6Lock Washer 2
PWC30/40-1068-2A/25409-125&
127 412 9510
--- Page 23 ---
PARTSPAGE
ALWAYSSPECIFY .UODEL AhiD SERL4L NUMBER MEN ORDERING PARTS
POWER WIRING FOR PWC 30/40 24V CURTIS PMC CONTROLLER
WITH TEE HANDLE INTERMEDIATE SECTION
FORWARD R
DRIVE
ITEM NO, PART NO,
1 29000262-000 200 Amp Fuse