The function and working principle, technical parameters and selection of leakage circuit breaker

Update date:2017-10-23 Source:maxge

.Leakage circuit breaker

(1) function: it is mainly used to cut off the power supply quickly when the person is electrocuted or leakage, to ensure the safety of the person and prevent electric shock. Some leakage protector also has overload, short circuit protection, for not frequent, power failure motive.

(2) working principle: when the normal work, no matter whether the three-phase load balance, through the zero sequence current transformer main circuit of three phase current phasor sum is equal to zero, so the second time in the winding generating induced electromotive force, the leakage protector in closed state. If a leakage or electrocution occurs, the sum of the three phase currents Is no longer zero, but Is equal to one current value Is. Is through the human body, the earth, transformer neutral point forming circuit, the zero sequence current transformer secondary side with the corresponding induction electromotive force, Is added to the trip, and when Is reaches a certain value, the trip action, promote the main switch of the lock, breaking the main circuit.

(3) parameters and types

Parameters: rated current, rated leakage action current, rated leakage action time.Leakage circuit breaker

Type: the action mode can be divided into voltage action type and current action type; According to the action mechanism, there are switch type and relay type; According to the number of poles and lines, there is a single pole, two poles, two poles, and so on.

(4) selection: selecting the leakage protector shall be selected according to the purpose of use and the operating conditions:


The purpose of preventing physical shock. Install at the end of the line, choose high sensitivity, quick type leakage protector.

In order to prevent the contact of electric shock for the purpose of the device grounding and the branch line, select the sensitivity, rapid type leakage protector.

In order to prevent the leakage of fire and protection lines, equipment for the purpose of the main route, should choose the sensitivity, delay type leakage protector.

Selected by power supply:

When protecting the single-phase line (equipment), select the single pole or two electrode leakage protectors.

To protect the three-phase line (equipment), choose the tripole product.

When there are three phases and single phases, three poles or four poles are chosen.

(5) use method

In selecting the number of the leakage protector, the number of lines that are protected must be adjusted to the number of lines that are protected.

Check the leakage reliability after the meter and the fuse, check regularly.


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