Page 11
The DC filter capacitors inside the controller are con-
nected electrically to the speed tap wires. The capacitors
take approximately 5 minutes to discharge when the
disconnect is opened. For this reason it is necessary to
wait at least 5 minutes after turning off power to the
unit before attempting to change speed taps.
DANGER
Disconnect power from unit and
wait at least five minutes to allow
capacitors to discharge before at-
tempting to adjust motor speed tap
settings. Failure to wait may cause
personal injury or death.
Motor Start-Up
When B3 begins start-up, the motor gently vibrates back
and forth for a moment. This is normal. During this time
the electronic controller is determining the exact position
of the rotor. Once the motor begins turning, the controller
slowly eases the motor up to speed (this is called “soft-
start”). The motor may take as long as 10-15 seconds to
reach full speed. If the motor does not reach 200rpm
within 13 seconds, the motor shuts down. Then the
motor will immediately attempt a restart. The shutdown
feature provides protection in case of a frozen bearing or
blocked blower wheel. The motor may attempt to start
eight times. If the motor does not start after the eighth try,
the controller locks out. Reset controller by momentarily
turning off power to unit.
One revolution
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
FIGURE 11
HIGH SPEED COOL (output from controller to motor windings)
MOTOR SPEED CONTROL WITH D.C. PULSE-WIDTH MODULATION
WINDING #1
WINDING #2
WINDING #3
LOW SPEED HEAT/COOL (output from controller to motor windings)
HIGH SPEED HEAT (output from controller to motor windings)
O volts
325VDC
One revolution
O volts
325VDC
O volts
325VDC
WINDING #1
WINDING #2
WINDING #3
O volts
325VDC
O volts
325VDC
O volts
325VDC
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
WINDING #1
WINDING #2
WINDING #3
O volts
325VDC
O volts
325VDC
O volts
325VDC
Motor speed is determined by the size of the electrical pulse sent to
the motor windings. The longer the pulse, the faster the motor.
One
Pulse
ÇÇ
ÇÇ
ON PULSE
OFF PULSE
ÇÇ
ÇÇ
WINDINGS TURNED OFF
The frequency of the pulses to the windings is 20KHz.
DO NOT ATTEMPT TO MEASURE THESE VOLTAGES.
WINDINGS TURNED ON
OUTPUT FROM CONTROLLER TO MOTOR WINDINGS
One revolution
