Specifications
Curtis PMC 1223/33, 1225/35, 1227/37 Manual
21
Speed Limit Pot
A speed limit pot allows the operator to adjust the speed of the vehicle at full
throttle. Wiring for the speed limit pot is shown in each of the basic wiring
diagrams (Figures 3 & 4, 6 & 7, 9 & 10). The speed limit pot should be sized so
that it does not affect the throttle input resistance and thus the throttle response.
A 100kΩ pot is recommended.
The speed limit pot is at its maximum speed setting when its wiper is shorted
to the throttle pot’s pot high connection (Pin 1). When the speed limit pot is in
its maximum speed position, the vehicle’s speed at full throttle corresponds to the
programmed maximum speed setting. The speed limit pot is at its minimum
speed setting when its wiper is shorted to the throttle pot’s pot low connection
(Pin 3). When the speed limit pot is in its minimum speed position, the vehicle’s
speed at full throttle corresponds to the programmed minimum speed setting.
For information on the programmable speed parameters, see Section 3.
The speed limit pot varies the vehicle’s speed linearly over the range between
the minimum and maximum speed settings in each mode. In the examples
shown in Figure 13, the Mode 2 maximum and minimum speeds (M2 max, min)
are set at 100% and 40%, and the Mode 1 maximum and minimum speeds (M1
max, min) are set at 60% and 20%.
2 — INSTALLATION & WIRING:
Throttle
Fig. 13 Effect of speed limit pot position on speed curves.
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PWM OUTPUT (percent)
M2
min
M2
max
THROTTLE (percent)
Speed limit pot in maximum speed position
100500
PWM OUTPUT (percent)
M2
min
M2
max
THROTTLE (percent)
Speed limit pot halfway
100500
PWM OUTPUT (percent)
M2
min
M2
max
THROTTLE (percent)
Speed limit pot in minimum speed position
100500
PWM OUTPUT (percent)
M1
min
M1
max
THROTTLE (percent)
Speed limit pot in maximum speed position
100500
PWM OUTPUT (percent)
M1
min
M1
max
THROTTLE (percent)
Speed limit pot halfway
100500
PWM OUTPUT (percent)
M1
min
M1
max
THROTTLE (percent)
Speed limit pot in minimum speed position
100500
MODE 2 OPERATION
MODE 1 OPERATION