RU2361310C1 - Diagnostic method for switching unit contacts gap - Google Patents

Abstract

FIELD: electric engineering.

SUBSTANCE: invention relates to electric engineering, particularly, to switching devices and may be used for disconnecting emergency currents. The method assumes to provide gap between insulated lever and clutch mechanism of switching device in on-position. For this purpose, interlock contact is used and fixed so that the distance between interlock contact switch-over key and insulated lever coincides with the value of gap in on-position.

EFFECT: improved safety, reliability of operation and extended lifetime of switching device.

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Description

The invention relates to electrical engineering, namely to switching devices, and is intended to disconnect emergency currents, for example, for switches protecting the electrical equipment of urban electric vehicles, railway traction substations.

A method for diagnosing contact failure of a switching device is known, for example, from the following source: Patent No. 333261 RU for utility model “Automatic high-speed circuit breaker” dated May 29, 2003. A circuit breaker based on this source based on the number of common essential features can be taken as the closest prototype.

This switch contains a frame, movable and fixed contacts, holding an electromagnet with a magnetic circuit and an armature, breaking the spring, contact pressing spring, lever and switching mechanism.

The main disadvantage of this design is as follows. During the operation of the switch, the contacts are subject to wear, which is associated with the transfer of material in the molten bridge when the contacts open. As the contact surfaces wear, the stroke in the contacts decreases. In this case, an air gap may appear between the contact surfaces in the closed state and, as a result, to the violation of the contact connection. To prevent such a danger, all opening contacts have a so-called additional stroke in the contacts (failure), the value of which for automatic high-speed switches does not exceed 3-6 mm. During continuous operation of the circuit breaker, the magnitude of the dip decreases, which reduces the reliability of the circuit breaker.

Summing up, we can note the following. To date, failure diagnostics as such are not used in switching equipment. The failure selection process is monitored by visual inspection of the equipment during inspection or repair. The disadvantage of this method is the occurrence of an emergency when choosing a contact failure until the next technical control, which can lead to failure of the switching device and damage to the protected equipment in both emergency and normal (nominal) operation.

The problem to which the invention is directed is to increase operational safety, reliability and increase the service life of the switching apparatus.

The technical result of the invention is the exclusion of the inclusion of the switching device when choosing the failure of the contacts, that is, when the contact surfaces wear.

This problem is solved in that a method for diagnosing a failure of contacts of a switching apparatus, including a movable and fixed contacts, disconnecting a spring, a contact pressing spring, including a mechanism that is connected to the movable contact by an insulating lever, by creating a gap (failure) between the lever and the switching mechanism in the on the position of the switching apparatus is supplemented by the following: the switching mechanism is equipped with a block contact, which is fixed in such a way that the distance between the switching button bl ok-contacts and the insulating lever coincides with the size of the dip in the on position of the switching device. When the contacts wear (selecting a failure), switching on the switching device is excluded by switching the button of the contact block, which transmits a signal to the control of the switching device.

An example implementation of the proposed method is illustrated in figure 1 and figure 2.

Figure 1 schematically shows the switching apparatus in the on position; figure 2 is the same in the off position.

The switching apparatus contains a frame 1, movable 2 and fixed 3 contacts, holding an electromagnet with a magnetic circuit 4 and an armature 5, disconnecting a spring 6, a contact pressing spring 7, a lever 8 and an electromagnetic switching mechanism 9. Anchor 5 and a magnetic circuit 4 are mounted on a common axis 10. The armature 5 is connected to the movable contact through the insulating rod 11. The contact pressing spring 7 is located between the switching mechanism 9 and the magnetic circuit 4. In this case, the switching mechanism 9 is connected to the magnetic circuit 4 through the lever 8, using springs 7 and 12. Spring 13 rests on the bracket 14, on which the block contact 15 is fixed.

The switching device operates as follows.

In the on position (figure 1), the magnetic circuit 4 and the armature 5 are attracted to each other due to the current in the coil of the holding electromagnet. The anchor of the switching mechanism 9 is in an attracted position due to the holding current in the coil of the electromagnet of the switching mechanism. The gap δ (contact failure) provides guaranteed contact closure of contacts 2 and 3 when they are worn.

The signal from the current sensor (or other emergency shutdown sensor) interrupts the current in the coils of the holding electromagnet and the switching mechanism. Under the action of the springs, the anchor of the switching mechanism, the lever 8, the magnetic circuit 4, the anchor 5 of the holding electromagnet and the rod 11, and with it the movable contact 2 go into the off position (figure 2).

When the contacts of the switch are worn out until the failure δ = 0 is completely selected, the lever 8 switches the block contact 15, which transmits a signal to the control station to turn off the switch. When a signal is sent to turn on, the switch will not turn on.

Thanks to the indicated design differences, increased reliability in operation and safety during operation of the switching apparatus are ensured.

Claims (1)

A method for diagnosing a failure of contacts of a switching apparatus, including a movable and fixed contacts, breaking a spring, a contact pressing spring, including a mechanism that is connected to a movable contact by an insulating lever, by creating a gap (failure) between the lever and the switching mechanism in the on position of the switching apparatus, characterized in that the switching mechanism is supplemented by a block contact, which is fixed in such a way that the distance between the switch button of the block contacts and the insulating lever agom coincides with the magnitude of the failure in the on position of the switching apparatus.

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