RU2795269C1 - Polarized high-speed electromagnet - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention is related to protective switching equipment and can be used to protect against overloads and short circuits of electrical installations and DC lines. A polarized high-speed electromagnet is a magnetic circuit, through the window of which a current-carrying bus, an armature, a spring and a permanent magnet are passed. The permanent magnet is installed in the magnetic circuit of the magnetic circuit parallel to the armature and is magnetized along the magnetic lines of the magnetic circuit. The armature doesn’t touch the permanent magnet in the initial or in the final position.

EFFECT: resistance to shock loads and reduction in size and simplification of the design of a polarized high-speed electromagnet

1 cl, 1 dwg

Description

The invention relates to electrical engineering, in particular to protective switching equipment, and can be used to protect against overloads and short circuits of electrical installations and DC lines.

To protect high power DC circuits and equipment, automatic high-speed switches are often used, the tripping time of which is a few milliseconds from the moment an emergency occurs, for example, when the current rises to an unacceptably large value. The automatic quick-acting switch has a device that is adjusted to a certain current - the so-called switch operating current, and when the current in the circuit reaches this value, the switch turns off. This device can be a release device - in this case it mechanically opens the circuit breaker mechanism, or operate as a current relay - that is, when triggered, a low-current contact is switched, which, in turn, gives the command to open the circuit breaker - as a rule, breaks the holding current of the high-speed circuit breaker. In some cases, as, for example, when protecting rectifiers from reverse currents, it is required that the trip current depend on the direction of current flow - the magnitude of the trip current when current flows in one direction differs from the trip current when current flows in the other direction, that is, a release or current relay must be polarized.

This function is performed by a high-speed electromagnet according to the RF patent for the invention 2322720. This electromagnet contains a U-shaped magnetic circuit, through the window of which a current-carrying bus, an armature and a magnetic shunt are passed, connected to the magnetic circuit rods and forming a magnetic circuit parallel to the magnetic circuit of the armature. A gap is made in the magnetic shunt, in which a permanent magnet is embedded, magnetized along the magnetic shunt. This electromagnet can be used both as a release and as an electromagnet for a current relay. However, the presence of a magnetic shunt significantly increases the design of the electromagnet and its weight.

Closest to the patented electromagnet is the design of the release mechanism according to the patent EP 2431991 A1.

This mechanism contains a magnetic circuit, through the window of which a current-carrying bus is passed, an armature and at least two permanent magnets mounted on the magnetic circuit so that the armature in the extreme position touches both magnets and closes the magnetic circuit of the permanent magnets.

This mechanism also has its drawbacks. After the armature of the mechanism is triggered, the current in the main circuit is interrupted by a switch that contains this release mechanism, and the armature returns to its initial position under the action of the spring, and since this movement occurs already without resistance forces, the armature can pick up a sufficiently high speed under the action of the spring. As a result, the armature hits the magnets after each operation, and, as you know, the characteristics of permanent magnets deteriorate from direct impacts, which will negatively affect the stability of the operation currents. In addition, in order to avoid distortions, the armature must always touch two magnets simultaneously, that is, machining must be performed with increased accuracy, which is technologically difficult to perform for a unit assembled from a set of thin sheets of electrical steel.

The invention solves the problem of creating a polarized high-speed electromagnet of reduced dimensions, technologically simple to manufacture and resistant to shock loads.

The technical result provided by the above set of features is to increase the strength to impact loads.

The essence of the invention is as follows.

A polarized high-speed electromagnet contains a magnetic circuit, through the window of which a current-carrying bus, an armature, a spring and a permanent magnet are passed. The permanent magnet is installed in the magnetic circuit of the magnetic circuit parallel to the armature and is magnetized along the magnetic lines of the magnetic circuit. The spring creates a force that counteracts the electromagnetic attraction force of the armature. To ensure speed, the magnetic circuit and the armature are laminated from thin sheet electrical steel. Anchor can make a straight line along the guides or can be attached to the levers mounted on the axis, in which case the movement will be along the part of the circle. Structurally, the armature is made in such a way that, when triggered at the end of the stroke, it does not touch the permanent magnet. The ratio of the sections of the magnetic circuit, armature and permanent magnet is calculated based on the required characteristics - depending on what the difference between the operation currents of different directions should be.

The invention is illustrated by the drawing, where in Fig. 1 schematically shows the inventive polarized high-speed electromagnet in the initial position (the armature is not pulled), where

1 - magnetic circuit;

2 - current-carrying bus;

3 - anchor;

4 - spring;

5 - permanent magnet;

6 - air gaps.

A high-speed electromagnet (Fig. 1) contains a magnetic circuit 1, through the window of which a current-carrying bus 2, an armature 3, a spring 4 are passed. A permanent magnet 5 is installed parallel to the armature 3, magnetized along the magnetic lines of the magnetic circuit. In the initial position, there are air gaps 6 between the armature and the magnetic circuit.

Polarized high-speed electromagnet works as follows.

The magnetic flux Fp (Fig. 1) of the permanent magnet 5 flows mainly through the magnetic circuit 1, and practically does not flow through the armature 3, since there are air gaps 6 between the magnetic circuit and the armature, which are a sufficiently large resistance for this magnetic flux. The magnetic flux F1, created by the current of the busbar 2, flows mainly through the magnetic circuit 1 and the armature 3 and almost does not flow through the magnet, since for this flux the permanent magnet 5 represents a much greater resistance than the magnetic resistance of the air gaps 6.

With a certain direction of the current flowing through the current-carrying bus 2, the magnetic fluxes Φ1 and Фp flow as shown in Fig. 1 arrows. In this case, in the magnetic circuit 1, these flows are added, which leads to saturation of the material of the magnetic circuit. The saturation of the material of the magnetic circuit leads to a significant increase in the magnetic resistance of the magnetic circuit 1, and, consequently, to a significant weakening of the flux Ф1. In this case, to attract the armature 3 to the magnetic circuit 1, a significant amount of current is required through the current-carrying bus 2.

If the direction of the current through the current-carrying bus 2 changes to the opposite, then the flux F1 will change its direction, and the direction of the flux F2 of the permanent magnet 5 will remain unchanged. Then, in the magnetic circuit 1, the fluxes Ф1 and Фп will flow in different directions, which will reduce the total flux, and, consequently, reduce the magnetic resistance of the magnetic circuit 1. In this case, the armature 3 will be attracted to the magnetic circuit 1 at a much lower current than in the first case.

This design is easier to manufacture than the prototype, as it does not require precise machining of inclined planes to ensure symmetry. In addition, in the patented design, the armature does not touch the permanent magnet in either the initial or final position, which protects the permanent magnet from impacts.

Thus, an easy-to-manufacture, shock-resistant and reduced in size polarized high-speed electromagnet is created.

Claims (1)

A polarized high-speed electromagnet containing a magnetic circuit, through the window of which a current-carrying bus, an armature, a spring and a permanent magnet are passed, characterized in that the permanent magnet is installed in the magnetic circuit of the magnetic circuit parallel to the armature and is magnetized along the magnetic lines of the magnetic circuit, while the armature is neither in the initial nor in end position does not touch the permanent magnet.

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