Novel fire cutoff phase-stagger protector for electric hoist

Abstract

The invention discloses a novel fire cutoff phase-stagger protector for an electric hoist, comprising a first limiting stopper and a second limiting stopper, wherein the first limiting stopper is connected between an electromotor and two parallel alternating current contactors in an electromotor control circuit; the pulling normally closed contact and the pushing normally closed contact of the first limiting stopper are respectively used for connecting two contacts of the main contacts of a first alternating current contactor and two contacts of the main contacts of a second alternating current contactor; the pulling normally closed contact of the second limiting stopper is connected with the pushing normally closed contact of the first limiting stopper; and the pushing normally closed contact of the second limiting stopper is connected with the pulling normally closed contact of the first limiting stopper. Cutoff limiting protection and power supply phase-stagger protection can be effectively realized for the electric hoist by the novel fire cutoff phase-stagger protector in the invention, the reliability is high, the novel fire cutoff phase-stagger protector also can provide effective and reliable protection even if the alternating current contactors are adhered or a main circuit is subjected to phase stagger in the overhauling process, and the accidents can be avoided.

Description

technical field [0001] The invention relates to an electric hoist, in particular to a novel fire-off and misphase protector for the electric hoist. Background technique [0002] At present, my country's wire rope electric hoist has gone through three stages of imitation, development, and improvement. CD and MD electric hoists are currently the largest and most widely used electric hoists in my country. According to the JB9009-1999 safety regulations for wire rope electric hoists, electric hoists are required It should have a wrong-phase protection function, but in the prior art, the electric hoist only has the upper and lower two-way limit function, no wrong phase sequence protection function, and no fire-off limit function. When the power supply phase sequence is wrongly connected, the motor cannot stop on time, which is easy Therefore, it is necessary to design a fire-break type phase sequence protector with fire-break and misphase protection. Contents of the invention ...

AI Technical Summary

Problems solved by technology

[0002] At present, my country's wire rope electric hoist has gone through three stages of imitation, development, and improvement. CD and MD electric hoists are currently the largest and most widely used electric hoists in my country. According to the JB9009-1999 safety regulations for wire rope electric hoists, electric hoists are required It should have a wrong-phase protection function, but in the prior art, the electric hoist only has the upper and lower two-way limit function, no wrong phase sequence protection function, and no fire-off limit function. When the power supply phase sequence is wrongly connected, the motor cannot stop on time, which is easy Cause accidents, so it is necessary to design a fire-break type phase sequence protector with fire-break and misphase protection

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