Vestil EPT-30 User Manual
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Curtis PMC 1207/1207A Manual
16
2 — INSTALLATION & WIRING: 1207 Controller
SWITCHES AND OTHER HARDWARE
Keyswitch
The vehicle should have a master on/off switch to turn the system off when not
in use. The keyswitch provides logic power for the 1207 controller, coil current
for the contactors, and shunt current (in compound motor applications). The
keyswitch must be capable of carrying these currents.
Main Contactor
A main contactor allows the 1207 controller to be disconnected from the battery.
In 24V applications a main contactor is optional, but in 36V applications a
main contactor is required. A heavy-duty single-pole, single-throw (SPST)
contactor with silver-alloy contacts is recommended, such as an Albright SW80
or SW180 (available from Curtis).
After initial closing of the contacts, inrush currents flow as the controller’s
internal filter capacitors are charged. A 250
Ω, 5W resistor (such as Curtis PMC
p/n MP-2) can be used across the contactor to precharge the capacitors and
reduce the inrush current through the contacts.
Forward/Reverse Contactors
For forward/reverse, a paired single-pole, double-throw (2
×SPDT) contactor is
recommended, such as an Albright DC88 or DC182 (available from Curtis).
With 4-terminal split field motors, two single-pole, single-throw (SPST) contac-
tors are typically used. The coil voltage should match the vehicle voltage. The
maximum allowed coil current is 1 ampere.
Forward/Reverse, Emergency Reverse, and Mode Switches
The direction input switches can be any type of single-pole, single-throw (SPST)
switch capable of switching the battery voltage at 10 mA.
Circuitry Protection Devices
For reverse polarity protection, a diode should be added to the control circuit. It
must be sized appropriately for the maximum contactor coil currents (and shunt
current, in compound motor applications). To protect the control wiring from
accidental shorts, a low current fuse (appropriate for the maximum current draw)
should be connected in series with the battery feed. These devices are both shown
in the wiring diagrams.