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Bi-directional
Fig. 13
twist-grip throttle with a
standard 20 k Ω pot and a
controller with the
optional 5k Ω –0 throttle
input.
Reduced speed
Fig. 14
operation (with standard
0–5k Ω pot).
Curtis PMC 1204X/1205X/1209/1221 Manual
A third method of accommodating bi-directional twist grip throttles uses a
standard potentiometer and a controller with a nonstandard throttle input. As
shown in Figure 13, a standard 20 kΩ pot is used, with its end terminals wired
SPEED
INCREASES
BOTH WAYS
20 kΩ
WARNING: with the input circuit shown in Figure 13,
potentiometer or wiring open circuits turn off the controller's
output. However, pot wiring shorts appear the same as a
normal zero ohm signal to the controller, and will produce
full speed operation if the short occurs while the power is on.
Reduced Speed Operation
Vehicle top speed can be easily limited, for safety or other reasons. A single resistor
connected in parallel with the throttle pot will reduce maximum speed according
to its resistance value, as shown in Figure 14. Use of a variable resistor makes
adjustment of maximum speed easier. With a switch, speed can be limited in
reverse only, or the speed reduction can be switched off—for example, to allow
authorized personnel to run the vehicle outdoors at full speed.
FASTER
OPTIONAL
SWITCH
SPEED
REDUCTION
RESISTOR
The speed reduction shown in the curve is approximate. The actual vehicle
top speed will depend on the motor characteristics and the vehicle load. You
together. The resistance goes from
5 kΩ at neutral to zero at the
extremes—the opposite of the
standard throttle input configu-
ration. Contact the factory if you
need this type of controller.
TO
THROTTLE
INPUT
25
20
15
TO
THROTTLE
INPUT
10
5
0
0
APPROX. % OF ORIGINAL TOP SPEED
WIRING
20
40
60
80
100
17
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