Troubleshooting for Common EMC Interference Problems
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9 Troubleshooting for Common EMC Interference
Problems
9.1 Leakage Current Suppression
The drive outputs high‑speed pulse voltage, which may easily incur high‑frequency
leakage current. The leakage current generated by each drive is higher than 100 mA.
The rated action current of the earth leakage circuit breaker (ELCB) therefore must be
above 100 mA. The drive may generate DC leakage current in the protective
conductor, a B‑type (delay‑time) ELCB therefore must be used.
If multiple drives are used, install an ELCB to each drive. The factors that affect the
leakage current are as follows:
● AC drive capacity
● Carrier frequency
● Type and length of the motor cable
● EMI filter
When leakage current causes the circuit breaker to trip, you should:
● Increase the rated operating current of the circuit breaker.
● Replace the circuit breaker with a new one with high‑frequency suppression.
● Reduce the carrier frequency.
● Shorten the output drive cable.
● Install a current leakage suppression device.
● Use a circuit breaker from recommended manufacturers such as Chint Electric and
Schneider.
9.2 Earth leakage Circuit Breaker Malfunction
When an earth leakage circuit breaker malfunctions, perform troubleshooting
according to the following table.
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