CN2251215Y

CN2251215Y - Open-phase protector for motor

Info

Publication number: CN2251215Y
Application number: CN 95220065
Authority: CN
Inventors: 冯清松
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-08-28
Filing date: 1995-08-28
Publication date: 1997-04-02
Anticipated expiration: 2005-08-28

Abstract

The utility model relates to an open-phase protector for a motor, which is composed of three capacitors which are connected into a star shape, a bridge rectifier and a relay. When a phase interruption accident arises, the voltage of a neutral point arises, and the voltage is rectified and drives directly the relay to cut off the coil power supply of the AC contactor of a main loop to achieve the purposes of power-down protection. The utility model has the advantages of reliable action of phase interruption protection, simple circuit, few parts and low cost, and the utility model is suitable for the phase interruption protection of various motors.

Description

Phase failure protector of electric motor

The utility model relates to a kind of open-phase protection device for electromotor, belongs to technical field of relay protection.

Motor is in operation the phase failure often takes place, and cuts off the electricity supply as untimely, can cause the consequence of burn-down of electric motor.The neutral point current potential took place and is changed to signal when general open phase protection utilized the phase failure, went control executing mechanism to cut off the electricity supply after shaping is amplified, and reached the purpose of protection motor.Traditional view thinks that this electric displacement can not directly drive the circuit breaker action, and therefore, open phase protection all is provided with some intermediate circuits, and only the neutral point current potential is used as control signal.The protective device complex circuit of making like this, cost is higher.

The purpose of the new reason of this practicality provides new departure of a kind of open phase protection, and its decapacitation is finished outside the open phase protection action, also should have circuit characteristics simple, with low cost.

The purpose of this utility model is achieved in that

A kind of phase failure protector of electric motor, it goes out capacitor C ₁, C ₂, C ₃And relay J forms, and described electric capacity is connected into star, and draw connector lug A`, B` respectively, these connector lugs of C` will be in use, between the A.C. contactor JC contact and motor in the access motor main circuit.The common port P of electric capacity succeeds the solenoid of electrical equipment J, and the other end connecting to neutral line O of solenoid, the normally-closed contact of J draw the self-keeping circuit of back serial connection motor major loop contactor.

Relay J also can adopt direct current relay, at this moment, needs to insert a bridge rectifier between O and P, and electrical equipment J is succeeded in the direct current output of rectification circuit, and J is a direct current relay, still is connected in series the self-keeping circuit of motor major loop contactor after the normally-closed contact of J is drawn.

Capacitor C ₁, C ₂, C ₃The appearance value be 2-10 μ f.

Press the phase failure protector that the utility model is made, circuit constitutes very simple, and open phase protection is reliable in action then, because components and parts are few, complete machine is with low cost; Be applicable to the various motor of star dihedral connection.

Below in conjunction with accompanying drawing the utility model is done further narration:

Fig. 1 is an electrical schematic diagram of the present utility model.

Three capacitor C in the utility model are connected into star, and when normally moving, the neutral point current potential is zero, and then its voltage that is added on the relay J is zero, and J can not move.And even three-phase voltage is asymmetric, its neutral point displacement is less, also can not make the relay J action.When the phase failure, neutral point current potential increasing degree is bigger, when reaching the operation voltage of J, and the J adhesive, its normally-closed contact disconnects, and cuts off the solenoid power supply of A.C. contactor, thereby disconnects major loop.In this course, owing to be inductive load, the voltage on the relay J is slowly to rise, as long as reach the operation voltage of J, just cut off the supply power voltage on the electric capacity, therefore, the solenoid of J is not considered to adopt the voltage magnitude that equals phase voltage, but selects between 12-36V.The appearance value of capacitor is selected between 2-10 μ, and withstand voltage requires more than the 400V.

When using direct current relay instead, coil working voltage is still pressed 12-36V and is selected, triode then the selection work electric current at 1A, withstand voltage more than 250V.

Claims

1, a kind of phase failure protector of electric motor; it is characterized in that; it is made up of capacitor C 1, C2, C3 and relay J; described electric capacity is connected into star; and draw connector lug A`B`, C` respectively; the common port P of electric capacity succeeds the solenoid of electrical equipment J, and the other end connecting to neutral line O of solenoid, the normally-closed contact of J draw the self-keeping circuit of back serial connection motor major loop contactor.

2, protector according to claim 1 is characterized in that, inserts a bridge rectifier between P and O, and electrical equipment J is succeeded in the direct current output of rectification circuit, and J is a direct current relay.

3, protector according to claim 1 and 2 is characterized in that, capacitor C 1, C2,

The appearance value of C3 is 2--10 μ f.