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Maintenance Operations
Controller or AM radio receives noise when Inverter is started.
Problem
Noise derives from
Inverter switching.
The ground fault interrupter is actuated when Inverter is started.
Problem
Leakage current flows
through the Inverter.
There is mechanical vibration.
Problem
The mechanical sys-
tem is making unusual
noise.
The motor vibrates
excessively and does
not rotate normally.
4-10
Probable cause
Take the measures to prevent
noise. Noise can be reduced to
some extent.
Probable cause
The Inverter performs internal
switching. Therefore, a leakage
current flows through the Inverter.
This leakage current may actuate
the ground fault interrupter, shut-
ting the power OFF.
Note: In addition, remember that a
leakage current increases in pro-
portion to the cable length. (Nor-
mally, approximately 5 mA of
leakage current is generated for
each meter of cable.)
Probable cause
Resonance is occurring between
the characteristic frequency of the
mechanical system and the car-
rier frequency.
Resonance is occurring between
the characteristic frequency of the
mechanical system and the out-
put frequency of the Inverter.
Motor Phase Interruption.
If one or two of the three phases
of the motor are open, the motor
will vibrate excessively and will
not rotate.
Correction
Lower the carrier frequency of the Inverter in
P14 to 4 kHz.
Install an Input Noise Filter on the power input
area of the Inverter.
Install an Output Noise Filter on the output
area of the Inverter.
Enclose the Inverter with a metal shield and
ground the shield.
Correction
Use a ground fault interrupter with a high leak-
age-current detection value (sensitivity amper-
age of 200 mA or more, operating time of 0.1 s
or more) or one with high-frequency counter-
measures for Inverter use. Reducing the car-
rier frequency value in P14 is also effective.
Correction
If the motor is running with no problems and
the machinery system is vibrating with a high-
pitched whine, it may indicate that there reso-
nance is occurring between the characteristic
frequency of the mechanical system and the
carrier frequency. To prevent this type of reso-
nance, adjust the carrier frequency value in
P14.
Install vibration-proof rubber on the motor
base to prevent the resonance of the mechani-
cal system.
Check that the motor is wired correctly without
any disconnection. The same phenomenon
will occur if the output transistor of the Inverter
is open and damaged. Check the balance of
the Inverter's output voltage as well.
Chapter 4
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