Troubleshooting
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Noise is Produced from an AM Radio or when the MxC is Started
If noise is generated by MxC switching, then take the following action:
•
Change the MxC's Carrier Frequency Selection (C6-02) to lower the carrier frequency. This will help to
some extent by reducing the amount of internal switching.
•
Install an Input Noise Filter at the MxC's power supply input area.
•
Install an Output Noise Filter at the MxC's power supply output area.
•
Use metal tubing. Electric waves can be shielded by metal, so encase the MxC with metal (steel).
•
Ground the MxC and motor.
•
Separate main circuit wiring from control wiring.
Ground Fault Interrupter Operates while the MxC is Running
The MxC performs internal switching, so there is a certain amount of leakage current. This may cause the
ground fault interrupter to operate and cut off the power supply. Change to a ground fault interrupter with a
high leakage detection level (i.e., a sensitivity current of 200 mA or greater per Unit, with an operating time of
0.1 s or more), or one that incorporates high frequency countermeasures (i.e., one designed for use with
inverter). It will also help to some extent to change the MxC’s Carrier Frequency Selection (C6-02) to lower
the carrier frequency. In addition, remember that the leakage current increases as the cable is lengthened.
Mechanical Oscillation
Use the following information when there is mechanical oscillation.
The machinery produces an irregular sound.
The following causes are possible.
There may be resonance between the mechanical system's characteristic frequency and the
carrier frequency.
The motor is running with no problems and the machinery is oscillating with a high-pitched whine. To prevent
this type of resonance, adjust the carrier frequency with parameters C6-02 (Carrier Frequency Selection).
There may be resonance between a machine’s characteristic frequency and the output fre-
quency of the MxC.
Either use the jump frequency functions in parameters d3-01 to d3-04 or install rubber padding on the motor
base to reduce oscillation.
