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µP-T System Description
GENERAL DESCRIPTION
The µp-T microprocessor controllers are self contained tem-
perature control units designed for RD-II Smart Reefer
truck units.
Model 30 units are powered by a diesel engine and Model
50 units are powered by either a diesel engine or an external
electric standby power source turning an induction motor.
The unit mounts on the upper front of the truck box and the
evaporator extends into the box. The compressor, condenser
and evaporator fans are driven by belts. Defrost is accom-
plished by means of hot gas when operating in Diesel mode
and hot gas and electric evaporator heaters when operating
in optional Electric Heat mode.
CAUTION: Dangerous single phase or three phase AC
power is present whenever the unit is operating in Electric
mode or whenever the unit is connected to external
standby power. Voltages of this magnitude can be lethal.
Exercise extreme caution when working on the unit.
µP-T Control System
The µP-T Microprocessor Control System consists of the
following main components:
• Microprocessor Power Switch
• Remote Control Panel
• µP-T Microprocessor
• Interface Board
•Sensors
• Refrigeration System Controls
• Engine Controls
• High Voltage Tray (Model 50 Units)
Microprocessor Power Switch
The microprocessor power switch applies 12 volts DC con-
trol power to the microprocessor. It is located just below the
control box on the street side of the unit. Main power to the
balance of the controls is supplied by the 50 amp circuit
breaker CB1. Note that when the Microprocessor Power
Switch is turned “off” that power is still applied to the Inter-
face Board and control circuits via CB1. To completely
remove power from the control system disconnect the unit
battery.
Microprocessor Power Switch
For additional information, see Operation and Diagnosis
Manual TK 41087.
Optional Electric Standby
(Model 50 Units Only)
The Electric Standby option allows the unit to be operated
on either the diesel engine or external electric power. The
units can be supplied to operate on either single phase or
three phase power.
CAUTION: High voltage AC power is present
whenever the unit is operating in Electric mode and
whenever the unit is connected to external standby power.
Voltages of this magnitude can be lethal. Exercise extreme
caution when working on the unit.
CAUTION: The Electric Power Icon will not
appear in the display if electric power is not present
(the unit is not plugged in), or if there are electrical volt-
age or phase problems while the power cord is connected
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