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Curtis PMC 1204X/1205X/1209/1221 Manual
1
Check for power to the controller
TEST
Leave the keyswitch off for these tests.
1-A
Verify that battery (-) connects to the B- terminal of the controller. Connect
1-B
voltmeter (-) lead to this point.
Connect voltmeter (+) to the battery side of the main contactor. Check for
1-C
full battery voltage. If it is not there, the trouble is in the battery pack, the
cables to it, or the power fuse.
Connect the voltmeter (+) lead to the controller B+ terminal. You should
1-D
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.
2
Check for main contactor operation and KSI
TEST
Turn the key on, place the forward/reverse switch in forward or reverse, and
2-A
depress the footpedal until its microswitch operates. (In these procedures,
we assume the footpedal is equipped with the recommended microswitch.)
This should cause the main contactor to operate with an audible click.
2-B
Connect the voltmeter across the contactor coil terminals. You should see
full battery voltage (minus the polarity diode drop).
The controller KSI terminal should also be getting full battery voltage.
2-C
Verify this by connecting the voltmeter (-) to the controller's B- terminal,
and the voltmeter (+) to the controller's KSI terminal.
If the contactor and KSI terminal are not getting voltage, that's the problem.
2-D
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 the flow:
TROUBLESHOOTING & BENCH TESTING
28
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