Motor control and protection switch with overload thermal memory protection function

Abstract

The invention discloses a motor control and protection switch with an overload thermal memory protection function. The motor control and protection switch comprises a motor, a three-phase switch, an overload thermal memory module, a first current transformer, a second current transformer and a third current transformer, wherein input ends of the first current transformer, the second current transformer and the third current transformer are connected with three phase lines of a three-phase power supply respectively; output ends of the first current transformer, the second current transformer and the third current transformer all are connected with three-phase terminals of the motor through the switch respectively; control ends of the first current transformer, the second current transformer and the third current transformer are connected with corresponding input ends of the overload thermal memory module; and the output end of the overload thermal memory module is connected with the three-phase switch by virtue of a wire. By the motor control and protection switch with the overload thermal memory protection function, the burnout condition that the motor is insulated and damaged due to a temperature rise can be avoided; the service lifetime of the motor is prolonged; and the motor control and protection switch can be used for preventing the motor from being damaged due to an over-high temperature.

Description

technical field [0001] The invention relates to an electrical switch. Specifically, it is a motor control and protection switch with overload thermal memory protection function used to prevent motor damage caused by excessive motor temperature. Background technique [0002] As we all know in the electrical field, most of the current motors use single-chip microcomputers to finally realize the on and off of the switch through protection functions such as three-phase current overload, three-phase current imbalance, overvoltage and undervoltage. When the motor operating current exceeds the set value, the switch will play a tripping role. If the current is too high during the operation of the motor but does not reach the set value, the switch will not trip and the motor will not be powered off. Because the current is too high during the operation of the motor, the temperature inside the motor will accumulate and the temperature inside the motor will rise. When the temperature...

AI Technical Summary

Problems solved by technology

When the temperature inside the motor rises to the maximum allowable temperature, it will cause the motor insulation to be damaged and burnt

It can be seen that although the single-chip microcomputer is used to realize the on and off of the switch through the protection functions of three-phase current overload, three-phase current unbalance, overvoltage and undervoltage, it cannot avoid the motor insulation damage caused by the temperature rise and be burned. The situation occurs, which shortens the service life of the motor

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