Wesley SCT-7750-8AC - Manual (Page 28)

Owner’s Manual and Service Guide – SC & SCT Series 28
COMPONENTS - ELECTRICAL
M OTOR
All Pack mule electric vehicles are equipped with Advanced
Motor and Drives “DL” Series Separately Excited DC motors
(Figure 21). The motor Field and Armature are completely
separate and are energized independently by the motor
controller.
F IGURE 21
C ONTROLLER
The PC Series electric vehicle is equipped with a Curtis
separately excited (Sep Ex) motor speed controller (Figure
22). These programmable controllers are simple to install,
efficient, and cost effective. The Curtis controller provides
smooth precise control of motor speed and torque. A full-
bridge field control stage is combined with a half-bridge
armature power stage to provide solid state motor reversing
and full regenerative braking without additional relays or
contactors.
The controller’s rugged IP53 housing and packaging are
built to with-stand shock and vibration. The controller is fully
programmable
through the Curtis 13XX handheld
programmer. In addition to configuration flexibility, the
programmer provides diagnostic and test capability. The
Curtis motor controller offers superior operator control of the
vehicle’s motor drive speed.
Features include:

Interlock braking with load sensor to meet required
braking distance without unnecessary harsh braking at
light loads

Maintenance monitor responds to preset vehicle
operating hours and drive hours as programmed by the
OEM

Two hour meters —total KSI-on hours and traction
hours —and the associated maintenance timers are built
into the controller

BDI calculations performed within controller

Estimates motor temperature based on field resistance
and cuts back maximum speed if the motor is overheated

Diagnostic checks for field open and field shorted faults

Supports PWM electromagnetic brake with maximum
continuous current of 2 amps

Supports Type 4 throttle

Active pre-charge of controller capacitor bank extends life
of main contactor

Compatibility with Curtis 1307/1311 handheld
programmers for quick and easy testing, diagnostics, and
parameter adjustment

Continuous armature current control, reducing arcing and
brush wear

Complete diagnostics through the handheld programmer,
the built-in Status LED, and the optional 840 Spyglass
display

Two fault outputs provide diagnostics to remotely
mounted displays

Regenerative braking allows shorter stopping distances,
increases battery charge, and reduces motor heating

Automatic braking when throttle is reduced provides a
compression braking feel and enhances safety

Brake/Drive Interlock meets ISO stopping distance
requirements

Ramp restraint feature provides automatic electronic
braking that restricts vehicle movement while in neutral

Meets EEC fault detect requirements

Linear cutback of motor drive current during over-
temperature or under-voltage

Linear cutback of regenerative braking current during
overvoltage

High pedal disable (HPD) and static return to off (SRO)
interlocks prevent vehicle runaway at startup

Internal and external watchdog circuits ensure proper
software operation

Fully protected inputs and short-circuit protected output
drivers
F IGURE 22
This manual covers the most commonly required information
as it pertains to the Pack Mule vehicles. For more detailed
instructions, contact Wesley International for a copy of the
complete manual for the Curtis motor controller, or download
a copy from www.packmule.com.