ELECTRICAL
4262930-Rev A 4-31
4
Reel Motor Circuit—Theory of
Operation
Reel Motor Circuit Components
Main Control Unit
The main control unit (MCU) manages all machine
functions based on user input and programmed settings.
Bail Potentiometer
The bail potentiometer (R2) is supplied 5 VDC from
MCU.
The bail potentiometer provides a 0–5 VDC input voltage
to the MCU terminal J2-32.
Mow Switch
The mow switch (SW1) is supplied 15 VDC from MCU.
When the mow switch closed, a 15 VDC input voltage is
provided to MCU terminal J2-13.
Reel Motor Controller Unit
The reel motor controller (U1) is supplied 48 VDC from
the MCU.
The reel motor controller provides an AC output and 5
VDC output to the reel motor. The reel motor controller
manages motor speed based on input from the MCU.
Reel Motor
Reel motor (M1) is supplied AC current from the reel
motor controller.
The reel motor hall effect sensors provides the reel motor
controller an input voltage to communicate motor speed.
Reel Motor Circuit Operation
See Figures 4-16 and 4-17.
Main control unit (MCU) terminal J1-1 provides +48 VDC
to reel motor controller terminal J7-1.
MCU terminal J2-31 provides +5 VDC to bail
potentiometer terminal 3.
When the bail potentiometer is adjusted, a 0–5 VDC
reference voltage is provided from bail potentiometer
terminal 2 to the MCU bail pot input terminal J2-32.
The reel motor controller (U1) provides +5 volts and a
signal ground to the traction motor (M2), powering the
motor hall effect and temp sensors.
The hall A, B, and C sensor output terminals provide a
signal to the reel motor controller hall A, B, and C input
terminals through the traction motor terminals J11-2,
J11-3, and J11-4.
The reel motor controller, motor tach output terminal J6-1
provides an AC signal to MCU reel motor tach input
terminal J2-17. The AC signal is used to indicate motor
speed. The tach signal is based on the reel motor hall
sensor signals provided to the reel motor controller.
The reel motor temp sensor provides a 0–5 VDC
reference voltage to the reel motor controller temp input
terminal J1-6. The reel motor controller, motor temp
output terminal J6-2 provides the temperature value to
the MCU reel motor temp terminal J2-12.
The MCU provides a ground (low) signal output from reel
motor enable terminal J2-8 to reel motor controller
terminal J6-5. This ground (low) enables motor operation.
The MCU provides an open/high or approximately 8 VDC
from the reel motor direction terminal J2-9 to reel motor
controller terminal J6-4. The 8 VDC signal turns the
motor in the CCW direction.
The reel motor controller provides three-phase AC
voltage to the traction motor through terminals phase A,
B, and C.
The MCU reel motor speed output terminal J2-21
provides a 0–5VDC reference voltage to the reel motor
controller motor speed input terminal J6-3. Depending on
the value of the signal provided from the MCU, the reel
motor controller will operate the reel motor at the speed
requested.
The MCU will display the reel motor controller fault icon
on the LCD display when a problem is detected in the
reel motor controller. The reel motor will not operate until
the problem is resolved.
The MCU will also display the reel motor fault icon on the
LCD display when a reel motor short circuit is detected or
the reel motor current draw exceeds a constant 25 amps.
The reel motor will not operate until the problem is
resolved.
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