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36
Fault
Check Point
Corrective Action
.Wiring of frequency setting circuit is
correct
Correct the wiring.
Operation (method selection) mode
setting is correct.
Check operation method selection
mode [constant Pn-01] by digital
operator.
Motor rotates but
variable speed is
not available.
Load is not excessively large.
Reduce the load.
Motor ratings (number of poles,
voltage) are proper.
Check the specifications and
nameplate.
Accel/decel ratio by speed changer
(gears, etc.) is correct.
Check speed changer (gears etc.)
Maximum frequency set value is
correct.
Check the max. Frequency set
value [constant Pn-02]
Motor r/min is too
high (low).
Voltage between motor terminals is
not excessively reduced. (Use
rectifier type Volt-meter)
Check V/f characteristic set value
[Constant Pn-02~08]
Load is not excessively large.
Reduce the load.
Load variation is not excessively
large.
˙ Reduce the load variation.
˙
Increase the inverter or motor
capacity.
Motor r/min is not
stable during
operation (Note)
3-phase or single-phase power supply
is used.
Connect an Ac reactor to the
power supply if single-phase
power supply is used.
Note: Because of motor and load (geared machine) characteristics, motor r/min becomes unstable or
motor current ripples. To correct these problems, changing the inverter control constants may be
effective. Refer to “FUNCTIONS FOR REDUCTION OF MACHING VIBRATION OR SHOCK”
on page 99 for details of control constants to be changed.
