SU1432631A1 - Automatic circuit-breaker - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to simplify the design and increase reliability. The purpose of the invention is achieved by making the maximum current splitter in the form of a final microswitch installed under a slow-moving contact 7 of a current-limiting device. At the same time, the contact of the final microswitch is connected to the control circuit of the remote trip release 5. When short-circuit currents appear, the slow-moving contact 7 rotates and causes the end microswitch to activate, the contact of which connects the remote disconnecting coil 5 to the power source, which leads to the disconnection of the automatic switch. 2 Il. S cl

Description

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The invention relates to electrical engineering, namely to current-limiting circuit breakers for automatic disconnection of electrical circuits during a short circuit,

The purpose of the invention is to simplify the design and increase reliability.

FIG. 1 shows a circuit breaker, common vi, c in fig. 2 is a circuit for disengaging a remote shutdown trip device.

The automatic switch consists of the base 1, to which the cover 2 is attached. On the basis of the arcing chamber 3 and the i-mechanism of the free release 4, which kinematically connects the remote shutdown release 5 to the moving contact 6, is located. The automatic switch consists of contact 6, a slow-moving contact 7 with a current-limiting device and a fixed contact 8 "The low-moving contact 7 is connected to a fixed contact 8 so that the low-moving contact 7 can revolve around its axis providing electrical connection to the fixed and slow-moving contacts. The overcurrent release 9 is designed as a final microswitch and is installed under the slow-moving contact 7. automatic power switch

Automatically works as follows.

In the event of a short circuit in the circuit breaker circuit, the slow-moving contact 7 of the current-limiting device is rotated around its axis under the action of the increasing current of the short circuit, which causes the overcurrent release to operate - the final microswitch 9, that acts on the remote trip release 5

When the overcurrent release trips, the contacts of the end switch SQ2 or 503, igai SQ4 (FIG. 2) are closed, on the connector P

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The power supply 5 is disconnected remotely by applying an electrical voltage, which leads to the disconnection of the circuit breaker.

The remote on-line shutdown of the circuit breaker is accomplished by pressing the SQ1 button,

Simplification of the design is achieved, therefore, by the fact that instead of an electromagnetic overcurrent release consisting of three nodes, a device is proposed from one node (a contact pair of microswitches). In addition, the electromagnetic overcurrent release requires additional components, which is associated with the characteristics of the electric shunt, with the mounting and selection of the location of the electromagnet, adjustment of the gap between the electromagnet core and the circuit breaker trip mechanism,

The overcurrent release, made in the form of a final microswitch, allows to increase the reliability of a circuit breaker. the following figure is m.

The reliability of the successive links of the device is determined by the product of the reliability of each link. If we assume that the reliability of all (the Links are the same (P), then the reliability of the electromagnetic release P g P., - P –P P. The reliability of the final RP switch Mp is significantly higher than the reliability of the electromagnetic release Pp77P, since P.: 1,

The presence of additional heat sources, such as coils of electromagnetic releases, leads to additional heating of the entire circuit breaker, which does not contribute to an increase in reliability. Elimination of these additional sources of heat by replacing electromagnets that are constantly under current (if the main contacts of the circuit breaker are flowing) with a microswitch whose contacts are open, if the current of the main contacts did not reach the currents k, s ,, increases reliability and service life of the automatic switch.

Claims (1)

The response time (turning) of an inert contact under the action of electrodynamic forces is 1-2 MG, and the response time of the electromagnet of the overcurrent during the occurrence of currents ke. 14t18 ms, which is confirmed by the test results of the A3710 and A3720 circuit breakers. The microswitch response time is 2-3 ms. Therefore, replacing an electromagnetic overcurrent release with a microswitch does not reduce the speed of the short-circuit current protection device, and therefore does not reduce the reliability of the protection according to this indicator. Invention Formula Circuit breaker containing base, cover, arcs a detachable chamber, a free-release mechanism, a remote disconnecting release with a control circuit, a contact system including a moving contact, a slow-moving contact of a current-limiting mechanism, a fixed contact, and an overcurrent release, characterized in that, in order to simplify the design and increase reliability, the overcurrent release is made in the form of a final microswitch installed under a slow-moving contact of the current-limiting mechanism and connected to the circuit pack ION releasers remote control.