SU1700635A1 - Protection device of electric circuits - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to electrical engineering, in particular, to overcurrent protection devices. The goal is to increase the sensitivity and speed of operation of the protective device of electrical circuits. Protection - the device contains two elastic contact leads fixed in cross section, between which there is a fusible element in the form of a ring. A dielectric bushing is placed in the casing, which is connected to the casing by a spring, having radial protrusions 1 ... 1 hp f-ly, 2 ill. 1l "H h t l IfT

Description

FIELD OF THE INVENTION The invention relates to electrical engineering, in particular, to overcurrent protection devices.

The purpose of the invention is to increase the sensitivity and speed of operation of the protective device of electrical circuits.

FIG. 1 shows a protective device, a general view; in fig. 2 - protective device sleeve.

The protective device contains two contact leads 1 rigidly fixed in the fixed case 2, between which is placed a fuse 3 in contact with them. The case 2 of dielectric material is coaxially located with the inner sleeve 4, which is connected to the case 2 by an elastic connection - a torsion spring 5 .

The sleeve 4 (FIG. 2) is a cylinder, at one end of which there is a blind hole for arranging the torsion spring 5, the second end faces a cylindrical surface of smaller diameter, at the end of which there is a blinker, for example, a signal flag 6. On the side the surfaces of the sleeve 4 are two symmetric spiral sector protrusions 7, which serve to dilute the contact- and conclusions 1 when turning.

The sleeve with its protrusions 7 statically expands the elastic contact leads 1, which stretch the jumper-fuse 3.

The protective device operates as follows.

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A fuse jumper 3 in the form of a ring is connected in series to the circuit to be protected. At the moment of overload, the current flows through the jumper-fuse 3 of firing both of its branches or one of them. The sleeve k under the action of the spring 5 begins to rotate, pushing its protrusions 7 with the contact leads, which in turn spread the fused jumper parts to a sufficient distance, shortening the time for the arc to exist. The control of opening of the electric circuit is carried out visually by changing the position of the flask 6 located at the end of the sleeve k

Because of the fused jumper in the form of a ring, there are two fusible branches, so the diameter of each branch can be reduced, and each branch will pass a current less than half the optimum. Thus, the sensitivity of the security device is increased.

The presence of a spinning sleeve, which expands the contact leads and thereby expands the ends of the burnt fuse, reduces the arc burning time, and the presence of a detachable fuse provides quick

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replacement of a burnt out fusible element.

Claims (2)

1. A protective device for electrical circuits containing two contact leads mounted on a housing, between which a fusible element is located, characterized in that, in order to increase sensitivity and response speed, it is equipped with a torsion spring and a sleeve of dielectric material with two symmetrical spiral sector protrusions located on its side surface, said dielectric sleeve is installed in the housing coaxially, partially protrudes from the housing and is connected to the housing by a torsion spring, the contact terminals are made elastic, and the fusible element is designed as a removable ring located on the protruding portion of the dielectric bushing and enclosing the contact terminals. 2. The device according to claim. Characterized in that it is provided with a blinker located at the end of the dielectric sleeve protruding from the housing. 7 3 FIG. I. FIG. 2