Curtis 1244 Manual, Rev. E
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3. If the intent is to make the loaded speed less than the unloaded speed
(for reasons of safety, efficiency, or reduced motor heating), then:
(i) Unload the vehicle and drive it on at ground with full throt-
tle applied. When the vehicle reaches maximum speed, observe
the armature current displayed in the programmer’s Test Menu.
(ii) Set the Field Map Start parameter to the observed armature
current value.
(iii) Load the vehicle and drive it on at ground with full throttle
applied. Further adjustments to the vehicle’s loaded speed can
now be made by varying the Field Map parameter. Increasing
the Field Map parameter value will decrease the vehicle’s loaded
speed, and decreasing the Field Map parameter value will increase
the vehicle’s loaded speed.
CAUTION: If the Field Map Start parameter is set too high, the motor’s
safe commutation region may be exceeded. If this is the case, reduce the
Field Map Start parameter to a safe value. en, adjust the Field Map
parameter as needed to reach the desired loaded top speed. Reducing
the Field Map parameter will help bring the loaded speed closer to the
unloaded speed. However, care must still be taken because it is possible
for too low Field Map values—like too high Field Map Start values—to
result in operation outside the motor’s safe commutation region.
6 — VEHICLE PERFORMANCE ADJUSTMENT