In the process of using leakage circuit breaker, tripping often occurs when using its frequency converter, so why?

这是因为我们在使用变频器时，它的输出波形中含有高次谐波，而电机及变频器与电机之间的电缆就会产生泄漏电流，该泄漏电流跟工频驱动电机时的电流相比之下会大许多，故而也就产生了跳闸现象。隔离断路器一般用于高压电器的控制。而塑壳断路器能够在电流超过跳脱设定后自动切断电流。

This is because when we use the frequency converter, its output waveform contains high-order harmonics, and the motor and the cable between the frequency converter and the motor will produce leakage current, which will be much larger than the current when the motor is driven by power frequency, so the tripping phenomenon occurs. Isolation circuit breakers are generally used for the control of high-voltage electrical appliances. The molded case circuit breaker can automatically cut off the current when the current exceeds the trip setting.

这种情况下我们还应当使用的就是漏电保护器。当漏电断路器的变频器操作输出侧的漏电流大约为工频操作时的3倍多时，外加电动机等处的漏电流，这时候我们所选择的漏电保护器的动作电流就应该大于工频时漏电流的10倍。

In this case, we should also use leakage protector. When the leakage current at the frequency converter operation output side of the leakage circuit breaker is more than 3 times that of the power frequency operation, plus the leakage current at the motor, the action current of the leakage protector we selected should be greater than 10 times that of the power frequency operation.