7-21
7
îš‹ If Peripheral Devices are Influenced by the Starting or Running Inverter
The following solutions are possible:
• Change the Inverter's Carrier Frequency Selection (C6-02) to lower the carrier frequency. This will help to
reduce the amount of transistor switching noise.
• Install an Input Noise Filter at the Inverter's input power terminals.
• Install an Output Noise Filter at the Inverter's motor terminals.
• Use shielded motor cables or a conduit. Metal shields electrical noise.
• Check the grounding of the Inverter and motor.
• Separate main circuit wires from control circuit wires.
îš‹ If the Earth Leakage Breaker Operates When the Inverter is Running
The Inverter’s output is pulse modulated, i.e. the output voltage consists of high frequency pulses (PWM).
This high frequency signal causes a certain amount of leakage current which may cause the earth leakage
breaker 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 higher, with an operating time of 0.1 s or more), and
one, which incorporates high frequencies countermeasures (i.e., one designed for use with Inverters). Lower-
ing the Inverter's Carrier Frequency Selection (C6-02) can also help, since the leakage current increases with
the cable length.
îš‹ If There is Mechanical Oscillation
Use the following information when there is mechanical vibration:
îš„Oscillation and hunting occur with V/f control
The torque compensation parameter settings may be incorrect for the machine. Adjust parameters C4-01
(Torque Compensation Gain) and C4-02 (Torque Compensation Delay Time). Decrease C4-01 carefully in
steps of 0.05 and/or increase C4-02.
Furthermore the Slip Compensation Delay Time (C3-02) can be increased or decreased.
îš„Oscillation and hunting occur with Open Loop Vector control.
The torque compensation parameter settings may be incorrect for the machine. Adjust parameters C4-01
(Torque Compensation Gain), C4-02 (Torque Compensation Delay Time Parameter) and C3-02 (Slip Com-
pensation Delay Time) in order. Lower the gain parameters and raise the delay time parameters.
If auto-tuning has not been performed, proper performance may not be achieved for Vector Control. Perform
auto-tuning or set the motor parameters manually.
îš„Oscillation and hunting occur with Closed Loop Vector control for IM and PM
The gain adjustment may be insufficient. Adjust the speed control loop (Automatic Speed Regulator, ASR) by
changing the C5- parameters. If the oscillation points overlap with those of the machine and cannot be
eliminated, increase the ASR Delay Time, and then readjust the ASR gains.
If auto-tuning has not been performed, proper performance may not be achieved for Closed Loop Vector Con-
trol. Perform auto-tuning or set the motor parameters manually.
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