72
Fault Corrective ActionPossible Cause
Motor rotates, but
variable speed
Wiring of frequency setting circuit is incor-
rect.
Correct the wiring.
does not work.
Load is too large. Reduce the load.
Motor speed is
too high (low)
Motor ratings (number of poles, voltage)
are incorrect.
Check motor specifications and name-
plate.
Accel/decel ratio by speed converter
(gears, etc.) is incorrect.
–––
Maximum frequency set value is incorrect. Check the maximum frequency set value.
Voltage drops excessively between motor
terminals.
Check the base frequency.
Motor speed is
Load is too large. Reduce the load.
unstable
Excessive load variation. Reduce load variation.
Increase Inverter or motor capacity.
3-3 Maintenance
3-3-1 Periodic Inspection
The 3G3XV requires a few routine checks to ensure trouble-free
operation. Be sure that the 3G3XV is kept clean, cool, and dry, and
follow the recommendations given in
1-3-1 Location
.
Before inspecting the Unit, turn off the power and make sure that
the CHARGE indicator is off.
Component Check For Corrective Action
Terminals, Unit mounting
bolts, connectors, etc.
Loosened screws or connectors Tighten
Cooling fins Build-up of dust and dirt Clean off with dry compressed air at a
pressure of 57 to 85 psi (4 to 6 kg⋅cm
2
).
Printed circuit board Accumulation of dust or oil Dust and oil can conduct electricity. Clean
the board if necessary. Replace Inverter
unit if dust and oil cannot be removed.
Cooling fan Abnormal noise or vibration Replace cooling fan
Power components Build-up of dust and dirt Clean off with dry compressed air at a
pressure of 57 to 85 psi (4 to 6 kg⋅cm
2
).
Smoothing capacitor Discoloration or odor Replace capacitor or Inverter.
3-3-2 High Voltage Test
Use an insulation resistance tester (500 V) to conduct an insulation
resistance test (high voltage test) on the main control circuit, as
described below.
1, 2, 3...
1. Remove the Inverter’s main circuit and control circuit terminal
wiring and perform the test only between the main circuit termi-
nals and ground G (E), as shown in the following figure.
Maintenance Section 3-3
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