Three-phase high-power overcurrent and overheating protector

Abstract

The invention discloses a three-phase high-power overcurrent and overheating protector. The three-phase high-power overcurrent and overheating protector comprises a shell, a bottom plate, a thermosensitive plate, three binding posts and three static contacts, and the three-phase high-power overcurrent and overheating protector also comprises a heating plate, a first short shaft, a support and three moving contacts. The first short shaft is perpendicular to the heating plate, the lower end of the first short shaft is fixedly connected with the center of the heating plate, a first through hole is formed in the center of the thermosensitive plate, the thermosensitive plate is sleeved on the first short shaft through the first through hole, the bracket is fixedly mounted on the bottom plate, the bracket comprises three vertical plates which are arranged at intervals and are perpendicular to or inclined to the bottom plate, each vertical plate is located between two adjacent binding posts,the peripheral surface of the heating plate is in sliding fit with each vertical plate in the direction perpendicular to the bottom plate, the peripheral surface of the thermosensitive plate is embedded in the upper part of each vertical plate, the three moving contacts are respectively fixed on the bottom surface of the heating plate, and the three moving contacts and the three static contacts are respectively and correspondingly arranged up and down. The three-phase high-power overcurrent and overheating protector can reliably work under the large-current working condition of 200A or above,and accidents such as phase loss of a three-phase loop can be avoided.

Description

technical field [0001] The invention relates to an electric protector, in particular to a three-phase high-power over-current and over-heating device which is arranged inside electrical equipment such as motors and compressors, and which can automatically cut off the power supply to prevent its damage when it is over-current and over-heated. protector. Background technique [0002] The existing three-phase built-in overcurrent and overheating protector includes a metal shell with an open bottom, a metal bottom plate that closes the bottom of the shell, a heat sensitive plate, three moving contacts, three static contacts and three binding posts; The upper ends of the binding posts respectively pass through the bottom plate and extend into the closed space formed by the shell and the bottom plate. The bodies of the three binding posts are respectively insulated and sealed with the bottom plate. The three static contacts are respectively fixed and installed on the upper ends of...

AI Technical Summary

Problems solved by technology

[0004] (1) Since the current flows to the thermal board through the terminal post, a three-phase loop is formed between the terminal post and the thermal board, and because the current intensity that the thermal board can withstand is small, usually only tens of A, when the loop current When it reaches 200A, the large current can easily damage the thermal board, and the current impact of more than 200A can instantly destroy the internal electronic structure and stress structure of the thermal board, making the protector fail instantly, so that it cannot protect the electrical equipment such as the motor. There is still no market for high-power over-current and over-heat protectors above 200A, and circuit breakers and contactors are usually used to replace them;

[0005] (2) During the use of the protector, due to the impact and ablation of the current, the difference in the amount of silver loss between the three sets of contacts is likely to cause a serious loss of silver in a certain set of contacts, resulting in the loss of silver in each set of contacts. The pressure between them cannot be consistent, and the pressure failure of one group of contacts will instantly affect the stability of other contacts, resulting in accidents such as "phase loss" in the three-phase circuit, which seriously affects the use safety of electrical equipment;

[0006] (3) The overcurrent and overheating protection value of the protector cannot be adjusted, resulting in low protection precision of the protector and narrow application range

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