Service manual

4. Apply AC power to frequency converter.
5. Give the frequency converter a run command
and slowly increase reference (speed command)
to approximately 40 Hz.
6. Using an analog volt meter or a DVM capable of
measuring true RMS, measure phase-to-phase
output voltage on all three phases: U to V, U to
W, V to W. All voltages must be balanced within
8 V. If unbalanced voltage is measured, refer to
6.4.2 Input Voltage Test.
7. Stop frequency converter and remove input
power. Allow 20 minutes for DC capacitors to
fully discharge.
8. Reconnect motor leads to frequency converter
output terminals (U, V, W).
9. Reapply power and restart frequency converter.
Adjust motor speed to a nominal level.
10. Using a clamp-on style ammeter, measure output
current on each output phase. All currents must
be balanced.
Troubleshooting
VLT
®
HVAC Basic Drive Service Manual
40 MG90X202 - VLT
®
is a registered Danfoss trademark
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