9.2 Troubleshooting
9-13
9.2.10 If There is Noise When the Inverter is Started or From an AM Radio
D
If noise is generated by Inverter switching, implement the following countermeasures:
• Lower the Inverter’s carrier frequency (constant C6-01). This will help to some extent by reducing
the amount of internal switching.
• Install an Input Noise Filter at the Inverter’s power supply input area.
• Install an Output Noise Filter at the Inverter’s power supply output area.
• Use metal tubing. Electric waves can be shielded by metal, so encase the Inverter with metal (steel).
• Ground the Inverter and motor.
• Separate main circuit wiring from control wiring.
9.2.11 If the Ground Fault Interrupter Operates When the Inverter is Run
D
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 oper-
ating time of 0.1 s or more), or one that incorporates high frequency countermeasures (i.e., one designed
for use with Inverters). It will also help to some extent to lower the Inverter’s carrier frequency (constant
C6-01).
In addition, remember that the leakage current increases as the cable is lengthened.
9.2.12 If There is Mechanical Oscillation
J
The machinery is making unusual sounds.
1. There may be resonance between the mechanical system’s characteristic frequency and
the carrier frequency.
D
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 C6-01 to C6-03.
2. There may be resonance between a machine’s characteristic frequency and the output fre-
quency of the Inverter.
D
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.
J
Oscillation and hunting are occurring with open-loop vector control.
D
The gain adjustment may be insufficient. Reset the gain to a more effective level by adjusting constants
C4-02 (torque compensation time constant), C8-08 (AFR gain), and C3-02 (slip compensation primary
delay time) in order. Lower the gain setting and raise the primary delay time setting.
D
Vector control will not perform if autotuning has not been performed. Perform autotuning separately
for the motor, or set the motor constants through calculations. Alternatively, change the control mode
selection (A1-02) to V/f control.
J
Oscillation and hunting are occurring with V/f control.
D
The gain adjustment may be insufficient. Reset the gain to a more effective level by adjusting constants
C4-02 (torque compensation time constant), C7-02 (hunting prevention gain), and C3-02 (slip com-
pensation primary delay time) in order. Lower the gain setting and raise the primary delay time setting.
J
Oscillation and hunting are occurring with flux vector control.
D
Thegainadjustmentmaybeinsufficient. Adjust the various types of speedcontrolloop(ASR)gain.(For
details, refer to page 6 - 38.)
D
If the mechanical system’s resonance point coincides with the Inverter’soperatingfrequencyandtheos-
cillationcannot beeliminatedinthisway,increasetheASRprimarydelaytime(constantC5-06)andthen
try adjusting the gain again.
D
Vector control will not perform if autotuning has not been performed. Perform autotuning separately
for the motor, or set the motor constants through calculations. Alternatively, change the control mode
selection (A1-02) to V/f control.
J
Oscillation and hunting are occurring with V/f w/PG control.
D
Thegainadjustmentmaybeinsufficient. Adjust the various types of speedcontrolloop(ASR)gain.(For
details, refer to page 6 - 45.)
D
If the oscillation cannot be eliminated in this way, set the hunting prevention selection (constant C7-01)
to “0” (disabled) and then try adjusting the gain again.
J
Oscillation and hunting are occurring with PID control.
D
Check the oscillation cycle and individually adjust the P, I, and D. (Refer to page 7 - 51.)
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