Curtis PMC 1209B/1221B/1221C/1231C Manual
17
Fig. 11
Alternate
forward/reverse control
wiring, which provides
arcless contactor switching.
Wired this way with an
HPD controller, the
vehicle will freewheel;
with a non-HPD
controller, the vehicle will
plug brake.
A2
M-
B-
B+
F
O
R
W
A
R
D
R
EVER
SE
M
A
IN
KEYSWITCH
INTERLOCKS
THROTTLE
MICROSWITCH
FUSE
POLARITY
PROTECTION
DIODE
F/R SWITCH
(DPDT, center off)
+
–
WIRING
Fig. 12
Standard throttle
pot, 0–5k
Ω
.
Throttle Wiring
Standard Potbox Wiring
If the throttle input to the controller is from a Curtis PMC potbox or footpedal,
the wiring is simple: just connect the two wires of the potbox/footpedal cable to
the two push-on terminals of the controller, as shown in Figures 9 and 10. It
doesn
’
t matter which wire goes on which terminal. The wires can be extended as
required.
IMPORTANT
:
All vehicles should have throttle-actuated microswitches to
protect against runaways in the event the forward/reverse switch becomes
stuck in either direction. If your potbox doesn’t have such a microswitch
built in, you should add one.
Any suitable potentiometer of 5 k
Ω
nominal resistance will work with the
standard throttle input of the 1209B/1221B/1221C/1231C controllers. As
shown in Figure 12, connection should be made to the wiper and to one outer
terminal of the pot so that resistance increases as the throttle is applied.
TO
THROTTLE
INPUT
FASTER
0
–
5
k
Ω
P
O
T
TO
THROTTLE
INPUT
0–5k
Ω
POT
FASTER