leakage switch

The leakage switch can be divided into three types according to the action type:

1) RCCB residual current operated circuit breaker

The residual current operated circuit breaker does not have overload protection and short circuit protection, only leakage protection.

2) RCBO residual current operated circuit breaker

RCBO residual current operated circuit breaker with overload protection and short circuit protection, also with leakage protection.

3) Residual current action relay

The residual current action relay has no overload protection and short circuit protection, and can not directly divide the circuit, only the leakage alarm function. The leakage protection function is generally implemented in combination with other electrical appliances such as circuit breakers or contactors.

Leakage circuit breakers can be divided into three types according to measurement and control methods: electromagnetic leakage circuit breaker RCD, electronic leakage circuit breaker RCD, and hybrid leakage circuit breaker RCD.

The difference is

1) Electromagnetic leakage circuit breaker RCD

The electromagnetic RCD consists of a zero-sequence current transformer (zero-sequence current transformer), an iron core, an armature, a permanent magnet, a demagnetization coil, and the like. The sensitivity of the electromagnetic RCD is poor, it is difficult to achieve 30 mA or less; the time from the start of leakage to the trip of the circuit breaker is within 0.1 seconds, with no delay time.

2) Electronic leakage circuit breaker RCD

The electronic RCD is also equipped with a zero-sequence current transformer (zero-sequence current transformer). When leakage occurs, the secondary winding of the zero-sequence current transformer outputs a leakage current signal to the electronic measuring component, and then the electronic component converts the leakage signal to drive the intermediate relay or the shunting coil of the circuit breaker so that the switching device or the circuit breaker trips.

3) Hybrid leakage circuit breaker RCD

When leakage occurs, the phase-separated zero-sequence current transformer secondary winding can output the residual current. The trip unit is an electromagnetic structure including an iron core, an armature, a permanent magnet, a demagnetizing coil, and the like. After the zero-sequence current transformer detects the residual current, the electronic component amplifies the residual current signal to excite the demagnetization coil and then trips the circuit breaker through the armature. This approach is often used for leakage measurement and protection of ACB and MCCB circuit breakers.

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