Selective protection switch

Abstract

A switch with selective protection function, comprising a trip rod (18), a first temperature sensing element (16), a second temperature sensing element (20) and an electromagnetic mechanism (22). Wherein, the tripping rod is movably arranged in the switch; the electromagnetic mechanism pushes the tripping rod when the circuit is short-circuited, so that the tripping rod moves from the first temperature-sensing element to the second temperature-sensing element, and keeps At the position of the second temperature sensing element. When the circuit is overloaded, the first temperature-sensing element pushes the trip lever to disconnect the switch after a delay; when the circuit is short-circuited, the second temperature-sensing element acts to push the trip lever to disconnect the switch; the first temperature-sensing element It is connected in series with the second temperature sensing element, and also includes a trip lever position reset mechanism. When the circuit is disconnected due to a short circuit, the reset mechanism resets the trip lever to correspond to the first temperature sensing element s position. The invention realizes the selective protection of the circuit during overload and short circuit by adopting common thermal sensitive element and simple selection device.

Description

technical field [0001] The invention relates to a switchgear, in particular to a switch with selective protection function. The switch is generally used in the technical fields of power transmission and distribution, generators, and electrical control, such as current switching equipment such as load switches, circuit breakers, and contactors, and their supplementary electrical equipment. Background technique [0002] The current selective switch equipment is widely used. For example, in the power distribution system, in order to reduce the power outage range once the line or equipment fails, it is required to only cut off the power of the faulty line, and the other lines are still powered normally, which requires protection. The superior switch has a selective protection function. [0003] The current selective protection is divided into current selectivity, time selectivity and energy selectivity. The current selectivity is realized by the different action currents of th...

AI Technical Summary

Problems solved by technology

Conventional current-limiting resistors use ordinary alloy resistance wires to be wound into coils. The coils generate a strong magnetic field and need to be wound in reverse and in parallel. The process is quite complicated.

Moreover, in order to avoid short circuit between windings, the resistance wire needs to be specially insulated, which increases the cost, and the final formed current-limiting resistor has a large volume, which is very inconvenient to use.

In order to avoid this problem, some existing technologies use a current-limiting resistor of a special material to be connected in parallel to the current path, such as a resistor of a ceramic material with a constant or negative temperature coefficient. In order to achieve a good effect on this current-limiting resistor The requirements are relatively strict, the processing materials are more complicated, and the sintering process is more complicated, which increases the cost

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