How does the automatic cut work?

Since the beginning of electricity use protection against overcurrents, that is currents, too high in comparison with the flow capacity of lines, the currents caused by malfunctions or wrong polzovayoniy the electric unit was the main problem.

Устройство автоматического выключателя

Device of the automatic cut.

In order that it is better to control and interrupt such currents, they were separated into currents of the peyoregruzka and short-circuit currents. The optimum ustroyyostvo which is completely solving such problem is the termoyomagnitny automatic cut (see the photo).

Such switch inside continuously measures current and if it exceeds defined values, automatically interrupts it during the set time.

The automatic cut is applied to protection of lines against the short circuit and against the overload (thermal protection). In addition, the automatic cut performs function of the normal switch. The resource of the automatic cut makes about 20000 cycles of inclusion and shutdown.
Any automatic cut has to disconnect the different short-circuit current. At household automatic cuts it makes from 4000 to 6000 And. The rated current at them fluctuates from 1 to 63 And. Automatic cuts happen one - two - three - and quadripolar.

At the overload current the active element is the bimetallic plate. It heats up, changes the foryoma, and it leads to operation of the mechanism of the releaser. The line is disconnected without formation of the arch.

At the short circuit the proceeding current is much higher, than at the overload, and active elements are the magnet coil and the arc-suppressing camera. Sharply vozrastayoyushchy magnetic flux in the coil also puts the releaser mechanism in action, contacts are moved apart, but, unlike the situation with the overload current, there is the electric duyoga, i.e. current is not interrupted. Further under the influence of magnetic force and the arisen high pressure of the ionized gases in the switch the arch moves towards the arc-suppressing camera, hits against its plates, is split up, cools down and disappears - current is broken off.

  1. regel

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