GE ZIS360NM Technical Service Manual page 19

White Wire (DC Common)
The white wire is the DC common wire used for
testing. During repairs, DC polarity must be
observed. Reversing the DC polarity will cause a
shorted motor and/or board.
Red Wire (Supply)
Each motor uses an internal electronic controller
to operate the motor. Supply voltage from the
main control board remains at a constant
12 VDC.
Blue Wire (Feedback/RPM)
The blue wire feeds rpm (speed) information to
the main control board, allowing the board to
maintain consistent fan speeds. Loss of feedback
from the blue wire will result in the fan accelerating
to maximum speed. Measure the fan rpm using
the frequency between the blue and white wires.
High speed - 195 to 200 Hz
Medium speed - 145 to 160 Hz
Note: Fan operates at the same speed in low and
medium.
Low speed - 145 to 160 Hz (same as medium)
Yellow Wire (Signal)
The yellow wire is the input wire from the main
control board. The main control board provides
8.1 VDC effective voltage for low speed, 8.1 VDC
effective voltage for medium speed, and 12.6 VDC
for high speed. The fan will operate in low speed
only when the fresh food thermistor is satisfied.
Note: When testing these motors:
• You cannot test with an ohmmeter.
• DC common is not AC common.
• Verify 2 voltage potentials:
a. Red to white - power for internal controller.
b. Yellow to white - power for fan.
• Observe circuit polarity.
• Motors can be run for short periods using a
9-volt battery. Connect the white wire to the
negative (-) battery terminal only. Connect the
red and yellow wires to the positive (+) battery
terminal.
– 17 –
Low Voltage DC
120 VAC
GEA01196