CN2305750Y

CN2305750Y - AC contactor phase-defect protector

Info

Publication number: CN2305750Y
Application number: CN 97215293
Authority: CN
Inventors: 谷耀军
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-04-25
Filing date: 1997-04-25
Publication date: 1999-01-27
Anticipated expiration: 2007-04-25

Abstract

The utility model relates to an emergency protective device for an electric device. The utility model is characterized in that an AC contactor is additionally provided with one contact which passes through a voltage dividing and current limiting circuit and then is connected with a rectifier, a filtering capacitor and a DC relay through a leading wire at one end of a starting button of the contactor, and the normally open contact of the relay is connected in series to a contact branch circuit which is connected in parallel with the starting button. The utility model is integrated with the AC contactor, and has the advantages of simple structure, few parts and reliable work, has protective function for the phase interruption of each phase of a three-phase power supply, and perfects the function of no-voltage protection of the AC contactor.

Description

The A.C. contactor phase-lacking protective device

The utility model relates to a kind of power consumption equipment emergency protective device, specifically a kind of protective device that prevents the phase failure.

A.C. contactor is the main electrical equipment in the various electrical control equipments, and normal and fuse, thermal relay are used, and the motor even load is played short circuit and overload protective function.Because ac contactor coil and control loop normally are connected across between certain two line voltage of three phase mains; thereby has certain o-volt protection function; when if the phase failure appears in the two-phase of institute's cross-over connection, A.C. contactor is deenergization voluntarily also, realizes open-phase protection.But to not connecting an other phase of contactor, as occur that the phase failure then can't detect and disconnect voluntarily, thereby cause phase-deficient operation, make electrical appliance damage occur.The CN89212631 patent disclosure a kind of threephase motor phase failure short-circuit protection contactor, this contactor is at base installation and control plate, and signal circuit is arranged on the control board.Signal circuit is to be connected into the star loop by three identical branch roads, three node tap three phase mains, and each route rectifier, divider resistance and relay serial connection constitute.All there is a normally opened contact to be serially connected on the contact branch road in parallel on each relay with start button.The used components and parts in sort signal loop are more, and structure is relatively complicated, makes the cost of whole device higher relatively, and operational reliability also descends to some extent.

The purpose of this utility model just provides a kind of simple in structure, reliable A.C. contactor open phase protection, to realize the safe operation of electrical appliance.

The utility model is achieved in that the 3rd contact is set on A.C. contactor, in order to connect another phase power supply outside the former contactor wiring.This joint connects the rectifier input after the dividing potential drop current-limiting circuit, another input of rectifier is connected on the collateral contact branch road of A.C. contactor start button, rectifier output connects direct current relay behind filter capacitor, a normally opened contact of relay is serially connected on the collateral contact branch road of start button.

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is a circuit diagram of the present utility model.

As shown in the figure, by stop button TA, start button QA, coil ZC, and constituted traditional A.C. contactor at the normally opened contact ZC1 of QA two ends parallel connection and three normally opened contacts that on three phase mains, are connected in series.On this contactor, newly establish a contact in order to connecting A phase power supply, original two contact tap B of contactor mutually with C power supply mutually.Newly establish contact and connect an input of bridge rectifier D through the dividing potential drop current-limiting circuit, another input of rectifier is connected on the collateral contact branch road of A.C. contactor start button QA.The dividing potential drop current-limiting circuit is made of resistance R and capacitor C 1 parallel connection.The output of bridge rectifier D meets direct current relay J behind filter capacitor C2, the normally opened contact J1 of relay J is serially connected on the collateral contact branch road of start button QA.Use the A.C. contactor of this band protective device can realize any open-phase protection to three phase mains.

The course of work of this device is, at three phase mains just often, press and start ammonium button QA, contactor coil ZC gets electric adhesive, make normally opened contact ZC1 and other three closings of contact, the B phase voltage is added to an end of rectifier through contact ZC1, and the A phase voltage is added to another input of bridge rectifier D after the dividing potential drop current-limiting circuit simultaneously.The direct current of rectifier output is added on the direct current relay J after capacitor C 2 filtering, makes relay J get electric adhesive, its contact J1 closure.This moment release button QA, circuit gets final product normal power-up, uses electrical work.When the phase failure of A phase, then relay J outage, contact J1 disconnects, contactor coil ZC outage, each contact deenergization.When the phase failure of C phase, coil ZC outage, each contact deenergization.When the phase failure of B phase, pass through dividing potential drop current-limiting circuit, rectifier, filter capacitor, relay J and contact J1 between A, the C phase, arrive contactor coil ZC at last, return the C phase, can form electric loop, but this impedance loop is very big, electric current is much smaller than the electric current of keeping of coil ZC, make contactor not keep attracting state and discharge, thus deenergization.The definite of the operating voltage range of A.C. contactor can realize by the capacitance-resistance value of adjusting in the dividing potential drop current-limiting circuit.If power supply phase shortage before work then lacks the A phase time, press QA, coil ZC adhesive, the contactor action, but relay J can not adhesive; Unclamp QA, coil ZC dead electricity, deenergization.When scarce B or C phase time, press QA, coil ZC can not adhesive, and contactor is failure to actuate.

The utility model is by newly establishing a power line contact, and increases a simple electric control circuit, makes A.C. contactor all can implement power-off protection to each phase phase failure of three phase mains, makes the o-volt protection function of this contactor more perfect.This device is made one with A.C. contactor, and it is simple in structure, and components and parts are few, and reliable operation can guarantee the safe operation of electrical appliance effectively.

Claims

1, a kind of A.C. contactor phase-lacking protective device; it is characterized in that this device is newly to establish a contact on A.C. contactor; this contact connects the rectifier input after the dividing potential drop current-limiting circuit; another input of rectifier is connected on the collateral contact branch road of A.C. contactor start button QA; rectifier output meets direct current relay J through filter capacitor C2, and the normally opened contact J1 of relay J is serially connected on the collateral contact branch road of start button QA.

2, protective device according to claim 1 is characterized in that described dividing potential drop current-limiting circuit is made of resistance R and capacitor C 1 parallel connection.