Electromagnetic release

Abstract

The invention provides a releasing electromagnetic device capable of restraining changes of an attractive force between connection faces of a movable armature and a fixed armature without increasing a connection area of the movable armature and the fixed armature. The movable armature (6) arranged on a yoke iron sheet (4) projectingly and freely is configured facing the fixed armature (10), a hollow cylindric permanent magnet (5) magnetized in an axes direction is configured around the fixed armature (10) and the movable armature (6), a flux density passing through the connection face of the movable armature (6) and the fixed armature (10) is set more than 1 tesla.

Description

technical field [0001] The invention relates to a release type electromagnetic device, which is especially suitable for tripping device of a circuit breaker which makes an electromagnet act when an overload current or leakage current flows through a main circuit so that a tripping mechanism can trip. Background technique [0002] Conventionally, circuit breakers and leakage circuit breakers have been provided with tripping devices for circuit breakers. The tripping device of such a circuit breaker can detect abnormal currents such as overload current and leakage current flowing in the main circuit, and trip the main mechanism part according to the detection signal at that time, thereby opening the main circuit. In recent years, use of a release type electromagnetic device provided with a release type electromagnet has been increasing as a tripping device of a circuit breaker. [0003] Figure 10 It is a cross-sectional view showing a schematic structure of a conventional re...

AI Technical Summary

Problems solved by technology

[0011] However, in the conventional release electromagnetic device, the magnetic resistance of the permanent magnet 205 seen from the coil 202 is large, so when the coil 202 is energized to eliminate the magnetic flux of the permanent magnet 205, the magnetomotive force required by the coil 202 increases. Big

Therefore, it is necessary to increase the number of turns of the coil 202, which not only increases the size of the electromagnet, but also causes a problem of cost increase.

[0012] In addition, in the method disclosed in Patent Document 1, the magnetic flux density of the engaging surface when the movable armature is engaged with the fixed armature is set to be 1 Tesla or less, and therefore the required engaging area must be increased. , so there is a problem that the coil is difficult to miniaturize

[0013] In addition, when the movable armature protrudes, dust and dust generated during circuit breakage enter the connecting surface between the movable armature and the fixed armature through the gap, reducing the attractive force generated by the permanent magnet, so there is a problem of poor environmental resistance.

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