Plastic-shell electromechanical integrated three-phase AC motor protector with energy storage and impact device

Abstract

The invention discloses a protection device for a three phase AC motor of mechanical and electronic integration with a plastic shell and an energy-storing percussive device, which is applicable to the protection of the three phase AC motor. The invention have a slight change on internal electric connection wires on the basis of a breaker with a plastic shell or a creepage breaker with a plastic shell having creepage protection function (also called residual current protection device). Furthermore, the invention increases a special delayer, a voltage loss releasing device, an energy-storing percussive device, three current detection transformers and a zero sequence current transformer, as well as allocates a corresponding central processing unit (CPU) and a relative circuit outside the device. The invention is applicable to automatic power-off in the case of phase-lacking, creepage, overload and locked-rotor of the three phase AC motor to the reach the function of protecting the motor and realize the specialization and automation of motor protection.

Description

technical field [0001] The invention relates to a three-phase motor protection device, in particular to a molded case electromechanical integrated three-phase AC motor protector (switch) with an energy storage impact device. Background technique [0002] There are three types of damage to three-phase AC motors: [0003] 1. The motor is overheated, mechanically shaken or damp due to long-term use, resulting in reduced or damaged insulation performance. The three-phase power line fed to the motor rubs against the motor casing, causing leakage, endangering human life and causing electrical fires. [0004] 2. Overload and stall: When the motor is working, the motor cannot run normally and is stuck due to the change of load, which is called stall. Once a stall occurs, the motor will be damaged due to overload and stall within a few seconds. [0005] 3. The three-phase motor needs to be supplied with three-phase power when it is working. Due to the la...

AI Technical Summary

Problems solved by technology

[0010] 1. It consists of two discrete components, thermal relay and AC contactor, which is inconvenient to install;

[0011] 2. In terms of protection performance, when using it, it must be accurately adjusted by a person with certain professional knowledge, and its sensitivity is extremely poor;

[0012] 3. There is no phase loss protection function and leakage protection function

[0016] 1. It must be completed by more than two components, namely the motor protector and AC contactor or automatic switch, which is difficult to debug and has low sensitivity;

[0017] 2. Most products lack leakage protection function

[0028] 1) When the voltage of the power supply system is low to a certain value, the leakage circuit breaker cannot work reliably and cannot protect the motor

[0029] 2) The three-phase circuit breaker with leakage protection function is equipped with a shunt release. When the trip is working, it is connected to the two phases of the three-phase power supply in parallel. The two-phase power supply connected to the release lacks any phase. , the release loses its working condition and cannot produce impact force. If the trip lever of the circuit breaker is knocked open, the circuit breaker cannot be broken, and the motor cannot be protected.

[0030] 3) General molded case circuit breakers do not have continuous stepless adjustable setting of working current and leakage protection function

[0031] 4) The impact force generated by the pressure-loss release is insufficient when the pressure is lost. In order to meet the impact force, the pressure-loss release must be made very large, occupying a large space and high production cost

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