Yaskawa P7 Drive User Manual - Manual (Page 162)

Diagnostic & Troubleshooting 6 - 18
If the Ground Fault Interrupter Operates When the Drive is Run
The Drive performs internal switching, so there is a certain amount of leakage current. This may cause an external ground fault
interrupter to operate and cut off the power supply. Whenever possible, use 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 Drives). It will also help to change the Drive'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 Vibration
Use the following information when there is mechanical vibration.
The application is making unusual sounds.
The following causes are possible.
There may be resonance between the mechanical system's natural frequency and the carrier frequency.
This is characterized by the motor running with no noise generation, but the machinery vibrates with a high-pitched whine. To
prevent this type of resonance, adjust the carrier frequency with parameters C6-02 to C6-05.
There may be resonance between an applications characteristic frequency and the output frequency of the
Drive.
To prevent this from occurring, use the jump frequency functions in parameters d3-01 to d3-04, or have the driven motor and
load balanced to reduce vibration.
Oscillation and hunting are occurring with V/f control.
The gain adjustment may be insufficient. Reset the gain to a more effective level by raising the value of C4-02 (Torque
Compensation Primary Delay Time Parameter) and then lowering the setting of n1-02 (Hunting Prevention Gain).
Oscillation and hunting are occurring with PI control.
If there is oscillation or hunting during PI control, check the oscillation cycle and individually adjust P and I parameters.
•Disable integral (I) control
•Reduce the proportional gain (P) until hunting stops
•Reintroduce the integral function, starting with long integral time values, to eliminate the P offset