Nortec T-448AC, Operator And Maintenance Manual

Page: 22 / 57

Maintenance
- 21 -
TRAVEL AT REDUCED SPEED
Check batteries.
Turn off all switches and disconnect charger. Wear face shield and gloves. Do not disturb any
battery connection to avoid sparks. Check the specific gravity of each cell. Cold batteries,
highly discharged batteries or dead cells are the most frequent causes of reduced travel speed.
Check potentiometer.
Turn off the key switch, disconnect potentiometer terminals. Check the resistance between
terminals.
Other causes of lower speed:
 dragging brakes;
 cold temperature (higher differential oil viscosity).
INTERMITTENT OPERATION
A bad potentiometer is the most probable cause of the following:
 acceleration is not constant;

maximum speed is erratic;
 sudden stop after a bump or shock;
 erratic starts, requiring several pedal cycles.
Erratic starts could also be the cause of a misadjusted potentiometer or micro-switch; the pot signal
must be less than 50 ohms when the micro-switch turns on.
PMC has a HPD safety feature that prevents the vehicle from moving if the accelerator pedal is
depressed before the key switch is ON and seat switch is activated.
PMC also has a SRO safety feature that prevents the vehicle from moving if the F/R switch is activated
before turning on the key switch and activating the seat switch.
The vehicle stops on a steep and long ramp or while towing a heavy load: the PMC monitors the
temperature of the motor and is also equipped with an internal thermal protection that cutback the
current until the PMC and/or motor has cooled down.
NO MOTION
Make sure that the PMC surface is clean and dry; check the terminal areas. Dust Particles or acid
contamination, can create current leaks and cause a PMC malfunction.
Check F/R switch
Turn on the key switch and set to forward. Check voltage between the forward terminal and the
B– post on the PMC, check voltage between the reverse terminal and the B– post on the PMC;
if both B+, replace the F/R switch.
Check switches and wiring
Disconnect control terminals on the PMC and check all control signals. If a switch pin does not
read B+, check wiring or replace the switch.