Haier GE NF96UV Service Manual page 12

Motor speed is determined by the size of the electrical pulse sent to
the motor windings. The longer the pulse, the faster the motor.
OUTPUT FROM CONTROLLER TO MOTOR WINDINGS
WINDINGS TURNED OFF
The frequency of the pulses to the windings is 20KHz.
DO NOT ATTEMPT TO MEASURE THESE VOLTAGES.
LOW SPEED HEAT/COOL (output from controller to motor windings)
One
Pulse
One revolution
325VDC
O volts
WINDING #1
325VDC
O volts
WINDING #2
325VDC
O volts
WINDING #3
HIGH SPEED HEAT (output from controller to motor windings)
One revolution
325VDC
O volts
WINDING #1
325VDC
O volts
WINDING #2
325VDC
O volts
WINDING #3
HIGH SPEED COOL (output from controller to motor windings)
One revolution
325VDC
O volts
WINDING #1
325VDC
O volts
WINDING #2
325VDC
O volts
WINDING #3
Figure 8. Motor Speed Control with D.C. Pulse-Width Modulation
WINDINGS TURNED ON
ON PULSE
Page 12
OFF PULSE
31-5000726 Rev. 0