Curtis 1244 Manual, Rev. E
21
CONTACTOR, SWITCHES, and OTHER HARDWARE
Main Contactor
A main contactor is recommended for use with any 1244 controller. A main
contactor allows the controller and motor to be disconnected from the bat-
tery. is provides a significant safety feature in that the battery power can be
removed from the drive system if a controller or wiring fault results in battery
power being applied to the motor.
A single-pole, single-throw (SPST) contactor with silver-alloy contacts
is recommended for use as the main contactor. It is not necessary to specify
the coils at the nominal battery pack voltage as long as the Contactor Pull-In
Voltage and Contactor Holding Voltage are programmed to accommodate
the coil’s voltage rating—see Section 3, page 46. e contactor coil should be
specified with a continuous rating if the Holding Voltage parameter is to be
set at 100%. Intermittent duty coils can be specified if they are used with ap-
propriate Holding Voltage values.
Keyswitch and Interlock Switch
e vehicle should have a master on/o switch to turn the system o when
not in use. e keyswitch input provides logic power for the controller. e
interlock switch provides a safety interlock to prevent operation when a me-
chanical brake is engaged or to ensure operator presence before the vehicle is
allowed to move. e keyswitch and interlock switch provide current to drive
the various contactor coils as well as the controller’s internal logic circuitry and
must be rated to carry these currents.
Forward, Reverse, Mode Select, and Pedal Switches
ese input switches can be any type of single-pole, single-throw (SPST) switch
capable of switching the battery voltage at 25 mA.
Reverse Polarity Protection Diode
For reverse polarity protection, a diode should be added to the control circuit.
is diode will prohibit main contactor operation and current ow if the battery
pack is accidentally wired with the B+ and B- terminals reversed. It should be
sized appropriately for the maximum contactor coil and fault diode currents
required from the control circuit. e reverse polarity protection diode should
be wired as shown in the standard wiring diagram (Figure 3, page 8).
2 — INSTALLATION & WIRING: Switches, etc.
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