Relay protection circuit

Abstract

The invention discloses a relay protection circuit, which comprises a controller, a first nand gate, a second nand gate, a first delay circuit, a second delay circuit, a signal drive circuit, a triode Q2, a photoelectric isolator, a silicon controlled rectifier, a first relay RLY 1 and a second relay RLY 2, wherein the elements are connected to form the circuit. The relay protection circuit has the advantages that as two delay circuits are arranged in the circuit to be matched with other elements, the electricity-passing-time of contacts of the relays is delayed relative to the closing time of the contacts, so that the phenomena that the contacts of the relays are electrified immediately when the relays are in contact and contact splashing matters are produced are avoided.

Description

technical field [0001] The invention relates to a protection circuit for a relay in a controller of an intelligent lighting control system. Background technique [0002] In the control of equipment such as motors or lights, many circuits are connected in parallel by several load units, so that the load power is very large, and the power is as high as 2000W-3000W. Because contact spatters are easy to be generated when a large load is switched on and off, they will adhere to the contacts. The greater the current, the easier it is to cause the contacts to stick and cannot be disconnected. [0003] When many lamps are in a cold state, the resistance is very small, almost close to an instantaneous short circuit, and the current is 5 times to 10 times larger than the normal operation when starting, so it is easy to cause damage to the relay contacts in the control circuit in an instant, causing the controller to fail. Shortened lifespan, failure. Especially the motor load is gre...

AI Technical Summary

Problems solved by technology

[0003] When many lamps are in a cold state, the resistance is very small, almost close to an instantaneous short circuit, and the current is 5 times to 10 times larger than the normal operation when starting, so it is easy to cause damage to the relay contacts in the control circuit in an instant, causing the controller to fail. shortened life, failure

Especially the motor load is greater at the moment of starting, so it is easy to damage the relay

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