CN2039071U

CN2039071U - Phase-failure protector

Info

Publication number: CN2039071U
Application number: CN 88216075
Authority: CN
Inventors: 张兼程
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-11-08
Filing date: 1988-11-08
Publication date: 1989-06-07

Abstract

The utility model relates to a phase-failure protector for a three-phase motor. The action energy source of the phase-failure protector is originated from the same one power source of a controlled motor. The phase-failure protector requires no additional device, and is suitable for motors of any power. When a malfunction occurs in a three-phase power supply, a relay closed motor can be disengaged from the three-phase power source by the sum of current vectors on two capacitors, and accordingly, the motor can be protected. The utility model of phase-failure protector has simple structure, convenient maintenance and low cost, being benefit for organized productions.

Description

Phase-failure protector

The utility model relates to a kind of emergency protective circuit device, particularly relates to a kind of phase failure protector that is used for threephase motor.

The phase failure protector of Xiao Shouing is specifically designed to powerful motor in the market; need set up time-delay relay or additional other auxiliary lines during use; product price is more expensive; the middle low power motor generally then relies on thermal relay double as open phase protection; because thermal relay is slow in reacting, so effect is undesirable.

The purpose of this utility model provides a kind of improved phase failure protector, and its action energy is directed to by the same power supply of controlled motor, need not attachment device, is applicable to the motor of any power, and has reduced manufacturing cost.

A kind of phase failure protector that is used for threephase motor described in the utility model comprises relay and auxiliary line; it also comprises three equivalent capacitance devices that connect into Y shape; each is connected one end of described three capacitors with A, B, C three; the other end is by " 0 " point; a termination " 0 " point of relay coil BJ, other end ground connection or connect the center line of three-phase four-wire system.

A kind of phase failure protector described in the utility model is simple in structure, with low cost, helps tissue production.During the three phase mains normal power supply; relay coil is in " rest " state; no heater element; so the requirement of environment for use is lower, when motor starting, need not to be provided with the auxiliary line such as time-delay relay; simplified the motor starting control circuit; it is with the watt level of controlled load, and symmetry whether, parameter such as power factor is irrelevant, can form the open phase protection automatic control circuit with electrical equipment such as the relay of any specification, contactor, the omnipotent automatic air circuit breakers of DW10 series.Very convenient when checking or keep in repair components and parts.

With reference to the accompanying drawings the utility model is elaborated below.

Fig. 1 is a kind of circuit theory diagrams of phase failure protector.

Fig. 2 is the application circuit of above-mentioned phase failure protector in magnetic starter.

Referring to Fig. 1; a kind of phase failure protector that is used for threephase motor comprises relay and auxiliary line; it also comprises three the equivalent capacitance device C1, C2, the C3 that connect into Y shape; each is connected the end of described three capacitor C1, C2, C3 with A, B, C three; another termination " O " point " O " point of C1, C2, C3 connects with the end of relay coil BJ, and the other end of BJ is the center line of ground connection or three-phase four-wire system then.

When three phase supply just often because the capacitance of three capacitors equates that formed three phase symmetry load, the relay coil no current passes through.If caused phase shortage for a certain reason, symmetry is destroyed, just there is electric current to pass through to move in the relay coil, its normally closed interlock disconnects thus, cuts off the power supply of contactor coil, and motor just breaks away from three phase mains.

See Fig. 2 again, magnetic starter comprises push-button switch TA, QA, contactor QC and thermal relay RJ, and controlled device is threephase motor D.Phase failure protector is by being connected on shown in the figure between contactor QC and the motor D.When three phase mains any phase time that broken, relay coil BJ action makes motor break away from power supply, has avoided the two-phase running of motor D thus.

Claims

1, a kind of phase failure protector that is used for threephase motor; It comprises relay and auxiliary line, it is characterized in that it also comprises three equivalent capacitance device C1, C2, C3 that are linked to be Y shape, and each is connected another termination " O " some an end of described three capacitors with A, B, C three.A termination " O " point of relay coil BJ, other end ground connection or connect the center line of three-phase four-wire system.