CN2408563Y

CN2408563Y - Phase lost protector for motor

Info

Publication number: CN2408563Y
Application number: CN 00201973
Authority: CN
Inventors: 黎显银
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-01-14
Filing date: 2000-01-14
Publication date: 2000-11-29
Anticipated expiration: 2010-01-14

Abstract

The utility model provides a phase-failure protector for a motor. The phase-failure protector for a motor is mainly composed of three inductors L1, L2 and L3 which have the same impedance and iron cores and are respectively connected with a three-phase line according to star connection, a star point is connected with a relay coil after rectified by a diode, and the normally closed contacts of a relay are connected with a control loop of a main contactor. When any phase in the three-phase power line lacks, the voltage of the star point voltage displaces and causes the relay to act after rectified by the diode. The electricity of the contactor is cut off when the normally closed contacts D and E are disconnected, and a phase-failure motor can not operate any longer. The utility model has the advantages of simple circuit, few elements, low cost and high reliability.

Description

Open phase protector of motor

The utility model relates to the open phase protector of motor that a kind of motor that is used to prevent that the three-phase electricity phase shortage from causing damages.

Prior motor open phase protector kind is more; but ubiquity circuit structure complexity; components and parts are many; shortcomings such as service behaviour is unreliable; for this reason; it is simple that the applicant once designed a kind of circuit structure; cost is low; the open phase protector of motor of good reliability; and applied for patent to Patent Office of the People's Republic of China; its number of patent application is 99212872.2; its primary structure is: connect three-phase power line by three symmetrical electric capacity respectively by star connection; its asterism is succeeded electric apparatus coil after the diode bridge rectification, the relay normally-closed contact inserts in the control loop of main contactor, but finds in use afterwards; electric capacity in its circuit is after repeatedly starting voltage is impacted; breakdown easily, cause the whole protecting device durable inadequately, the life-span is short.

At above shortcoming, the utility model provides a kind of reliable operation, and circuit is simple, and cost is low, the open phase protector of motor of long service life.

Solution of the present utility model is: it is to utilize three-phase imbalance neutral displacement principle equally, respectively connect three-phase power line with the inductor of ribbon core by star connection by three impedance phases, its asterism is the cut-in relay coil after the diode bridge rectification, and the relay normally-closed contact inserts in the control loop of main contactor.

The utility model has the advantages that: adopt inductor and without capacitor, avoided making whole protecting device short shortcoming in useful life because of capacitor is punctured by starting voltage easily in circuit, and line construction is simple, cost is low.

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

Fig. 1 is the utility model circuit structure schematic diagram.

Fig. 2 is that the utility model is at the operating protection winding diagram of motor.

Among Fig. 1, three impedance phases insert three-phase power line A, B, C with inductor L1, L2 and the L3 of ribbon core respectively by star connection, and its asterism N is cut-in relay J coil behind diode D1, D2, D3 and D4 bridge rectifier.Among Fig. 2; in the control loop of relay J normally-closed contact D, E incoming transport contactor C; X1, X2 and X3 are respectively three phase mains; HK is a threephase switch, and QA is a starting button, and TA is a stop button; C is the A.C. contactor control coil; HR is the A.C. contactor main contacts, and DJ is a motor, and BH is this protector.

Its operation principle is: when the normal distribution of three phase mains, asterism N voltage is low or be 0, the input of no-voltage electric current, relay J is failure to actuate, when arbitrary when cutting off the power supply mutually in the triple line, and asterism N electric voltage displacement, it will be by the synthetic alternating voltage of other two-phase vector addition, behind diode D1, D2, D3 and D4 bridge full-wave rectifier, input relay J coil, the actuating of relay, disconnect normally-closed contact D, E, this moment main contactor C coil blackout, contactor loss of excitation and tripping outage, the phase shortage motor does not rerun.

Claims

1. open phase protector of motor; comprise inductor, diode and relay; it is characterized in that: three impedance phases insert three-phase power line A, B, C with inductor L1, L2 and the L3 of ribbon core respectively by star connection; its asterism N is cut-in relay J coil behind diode D1, D2, D3 and D4 bridge rectifier, and relay J normally-closed contact D, E insert the control loop of main contactor C.