Transistor Controller; Theory Of Operation; Basics Of Circuit Operation - prime mover smx45 Master Service Manual

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Transistor Controller

1. Theory of Operation

Interchanging the transistor controller
WARNING
with another truck model could cause
internal
controller. The warranty will be void if
the transistor controller is interchanged
from one truck to another!
The transistor controller is programmed specifically for this
truck. It is microprocessor based and programmable
designed for separately excited motors. The transistor
controller provides smooth control of the traction (drive) motor
utilizing four distinct operating modes. An LED is built into the
transistor controller that communicates controller status.

1.1. Basics Of Circuit Operation

The transistor controller provides both armature and field
outputs. Through these outputs, it regulates the voltage and
current applied to the motor according to it's programmed
motor control algorithm. This programmable motor control
algorithm allows the user to optimize truck performance
based on their application. The polarity and magnitude of the
field is controlled to provide solid state, contactor-less
direction control and plug braking.
As the transistor controller is powered up, it performs an
internal self test.
• A short between M- and Ground.
(Insures the M- output or power MOSFETs are not
shorted.)
• Continuity in the field coil.
(Occurs each time forward or rearward travel is
selected.)
Selecting either tractor-first or forks-first travel selects the
direction of current flow in the field. The voltage and current in
the armature circuit raises when the throttle increases. The
field current will then follow a predetermined current map to
match the armature current. In this manner, the motor is kept
Master Service Manual 2006-12-12
F-code Section
PT S5.7
Transistor Controller
Version no T-code
001 SMX
failure to the
C-code
5460
transistor
239