Nidec Control Techniques HVAC Drive H300 HMI Bypass, Installation And Commissioning Manual

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46 HMI Bypass Controller Installation and Commissioning Guide
Symptom Indications Corrective Actions
Motor does not
rotate when Bypass
mode is selected and
HAND is pressed or
AUTO is pressed and
the Auto-Run input
is ON - Check mechanical motor to load couplings
are intact
- Ensure that motor connections are made
and no bypass to motor disconnects are open
- Check that the mechanical load is not
binding
- If Bypass contactor is not closed check
control transformer and contactor coil
Fuses blow on
power up - Check VFD input wiring
- Replace VFD (see Section 6.4 for instructions)
Input circuit breaker
trips on power up - Check control transformer
- If fuses are blown see “Fuses blow” on
power up
Input circuit breaker
trips when a Bypass
run is initiated - Check motor cables
- Check motor direction
- Check motor