Toyota Pallet Truck Service Manual
Systems Overview
Theory of Operation
00700-CL390-04, Issued: 2 February 2004
3-9
grip. This shifts the motor controller from speed
mode M1 to mode M2 (forks first) or mode M4
(tractor first). The rabbit command is “latched”
until the twist grip is returned to neutral or the
brake (deadman) switch is opened.
Motor Controller
The basic functions of the motor controller
include:
•
Direction Control
section: controls the drive
motor direction by manipulating the drive
motor field polarity according to the
directional switch inputs (SW3, SW4).
•
Throttle Control
section: controls the drive
motor speed and torque by monitoring
relative position change of the wiper in the
travel potentiometer wrt the static neutral
position. Infinitely variable motor speed is
accomplished by separate control of field
and armature current.
•
Emergency Reverse
circuitry: controls the
override of the directional travel control.
•
Main Contactor (M1)
control
•
Diagnostics
section: continuously
monitors the travel circuits for fault
conditions and responds appropriately,
shutting down travel in some cases.
