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Curtis PMC 1204X/1205X/1209/1221 Manual
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 PMC
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, with two exceptions. 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.
The same noise may indicate overtemperature. The controller shifts fre-
quency during overtemperature from its normal 15 kHz to 1 kHz, providing an
audible tone to alert the operator to the overtemperature condition.
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 PMC 1204X/1205X/
1209/1221 controllers are designed to protect against damage caused by low
TROUBLESHOOTING & BENCH TESTING
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