Jacobsen Eclipse 322, Repair Manual

Page: 130 / 336

4-56 4222983 Second Edition
ELECTRICAL
4
With the traction pedal in the forward or reverse position,
AC power is provided from TCU AC motor output
terminals J43-U, J43-V, and J43-W to traction motor AC
motor terminals J45-U, J45-V, and J45-W. To control the
speed of the traction motor, the TCU varies the frequency
of the AC voltage applied to the AC motor terminals. To
control the direction of the traction motor, the TCU
changes phase of the AC voltage applied to the AC motor
terminals.
The TCU encoder 1 input terminal J44-5 connects to
traction motor encoder 1 output terminal J74-B. The TCU
encoder 2 input terminal J44-6 connects to traction motor
encoder 2 output terminal J74-C. The encoders provide
to the TCU the direction and movement data of the
traction motor.
When the TCU needs to slow the traction motor, the TCU
will change the phase between the three AC motor
terminals to magnetically slow down the traction motor.
As the motor is slowed, energy is created. The TCU
rectifies this energy and places it on the 48 volt power
bus (regenerative braking).
The traction motor temperature sensor output terminal
(J46-A) provides a signal to TCU motor temperature
sensor input terminal (J44-16). If the motor temperature
rises above 356° F (180° C), the TCU communicates this
condition to the MCU. Now the MCU instructs LCD to
turn on the alarm and display a fault code. The controllers
communicate through the CAN system.
The MCU automatically turns on and off the traction
control unit fan. The TCU has an internal temperature
sensor that monitors the temperature of the heat sink.
The MCU monitors the status of the TCU temperature
sensor through the CAN system. To turn on the fan, the
MCU fan output terminal (J3-4) provides a ground to the
traction control unit fan.
The optional third wheel drive circuit operates the same
as the traction drive circuit. The pedal and brake position
sensor signals are shared between the two controllers.
Also, the forward and reverse signals are shared.
Over Voltage Limit Monitor
During regenerative braking, the regenerative voltage
produced by the traction motor is routed by the TCU to 48
volt power bus to charge the 48 volt battery pack.
If the battery pack is fully charged, the excess
regenerative voltage on the 48 volt power bus is diverted
to ground by the over voltage limit monitor (OLM) through
the resistor bank.
The OLM will alternately divert power to ground between
the four resistors within the resistor bank, giving the
resistors time to cool.