If There Is Noise When The Inverter Is Started Or From An Am Radio; If The Ground Fault Interrupter Operates When The Inverter Is Run; If There Is Mechanical Oscillation - YASKAWA Varispeed F7 Instruction Manual

Autotuning has not been performed for vector control
Vector control will not perform if autotuning has not been performed. Perform autotuning, or set the motor
constants through calculations. Alternatively, change the Control Method Selection (A1-02) to V/f control (0
or 1).

If There is Noise When the Inverter is Started or From an AM Radio

If noise is generated by Inverter switching, implement the following countermeasures:
Change the Inverter's Carrier Frequency Selection (C6-02) to lower the carrier frequency. This will help to
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some extent by reducing the amount of internal switching.
Install an Input Noise Filter at the Inverter's power supply input area.
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Install an Output Noise Filter at the Inverter's power supply output area.
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Use metal tubing. Electric waves can be shielded by metal, so encase the Inverter with metal (steel).
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Ground the Inverter and motor.
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Separate main circuit wiring from control wiring.
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If the Ground Fault Interrupter Operates When the Inverter is Run

The Inverter 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 Invert-
ers). It will also help to some extent to change the Inverter's Carrier Frequency Selection (C6-02) to lower the
carrier frequency. In addition, remember that the leakage current increases as the cable is lengthened.

If There is Mechanical Oscillation

Use the following information when there is mechanical oscillation.
The machinery is making unusual sounds.
The following causes are possible.
There may be resonance between the mechanical system's characteristic frequency and the
carrier frequency.
If the motor is running with no problems and the machinery is oscillating with a high-pitched whine, it may
indicate that this is occurring. To prevent this type of resonance, adjust the carrier frequency with constants
C6-02 to C6-05.
There may be resonance between a machine's characteristic frequency and the output fre-
quency of the Inverter.
To prevent this from occurring, either use the jump frequency functions in constants d3-01 to d3-04 or install
rubber padding on the motor base to reduce oscillation.
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