CN201365217Y

CN201365217Y - Double-delta-winding transfer start circuit of three-phase motor

Info

Publication number: CN201365217Y
Application number: CNU2009201418194U
Authority: CN
Inventors: 陈雅民; 王凯
Original assignee: AO Smith Electrical Products Suzhou Co Ltd
Current assignee: Thunder Electric (suzhou) Co Ltd
Priority date: 2009-02-26
Filing date: 2009-02-26
Publication date: 2009-12-16
Anticipated expiration: 2019-02-26

Abstract

The utility model discloses a double-delta-winding transfer start circuit of a three-phase motor. The start circuit comprises two groups of three-phase windings and two contactors, wherein the head ends of a first, a second and a third coil of the first group of three-phase windings are respectively connected with the tail ends of the first, the second and the third coil of the second group of three-phase windings, and then connected with a three-phase power source through three transfer switches of the first contactor respectively; simultaneously the tail ends of the first, the second and the third coil of the first group of three-phase windings are respectively connected with the head ends of the third, the second and the first coil of the second group of three-phase windings and then connected with one end of the three transfer switches of the second contactor respectively, while the other end of the three transfer switches of the second contactor is respectively connected with the three-phase power source through the three transfer switches of the first contactor. The start circuit can effectively solve the defects of the existing three-phase motor such as heavy start current, multiple used contactors and easy overheat caused by the participation of only part of coils in starting.

Description

Two triangle winding changing-over start-up circuits of three phase electric machine

Technical field

The utility model relates to a kind of start-up circuit of three phase electric machine, especially a kind of pair of triangle winding changing-over start-up circuit.

Background technology

A lot of middle-size and small-size three phase electric machines adopt star-triangle start method or coil sections startup method to reduce starting current more at present, the start-up circuit that is dependent on the former startup method and produces exists contactor to use more shortcoming (needing 3 contactors usually at least), if capacity motor is bigger, then cost allowance is bigger; And be dependent on the latter's startup method and there is following shortcoming in the start-up circuit that produces: owing to only use coil sections when starting, so detent torque is less than normal and overheated burning easily.

Summary of the invention

The utility model purpose is: at the deficiency of the existing three phase electric machine start-up circuit of mentioning in the background technology, and provide a kind of two triangle winding changing-over start-up circuits of three phase electric machine, it not only can only need two contactors to realize that just the low current of motor starts, save motor cost, and can make all coils all participate in the startup of motor, the fail safe that starts with further raising three phase electric machine.

The technical solution of the utility model is: a kind of two triangle winding changing-over start-up circuits of three phase electric machine comprise two group of three phase winding and two contactors; Wherein the head end of first, second of first group of three phase winding and tertiary coil connects three phase mains through three reversing switches of first contactor respectively respectively with after the end of first, second and tertiary coil of second group of three phase winding is connected again; Simultaneously the end of first, second of first group of three phase winding and tertiary coil then respectively with second group of three phase winding the 3rd, second with an end that is connected on three reversing switches of second contactor after the head end of first coil is connected respectively, the other end of three reversing switches of second contactor is then respectively through three reversing switches connection three phase mains of first contactor.

The utility model is when electric motor starting, three reversing switches in first contactor at first close, six coil first and last ends of first group of three phase winding and second group of three phase winding linked to each other and constituted a big delta-connected circuit this moment, and the coil resistance of circuit is equivalent to two resistances after the three-phase windings in series at this moment.And after the motor operation, three reversing switches in second contactor again close, this moment first group of three phase winding with second group of three phase winding in three coils respectively first and last link to each other and form two little delta-connected circuits, and access three phase mains after the head end of three coils links to each other with the head end of three coils in second group of three phase winding respectively in first group of three phase winding.This moment, the coil resistance of circuit was equivalent to two three resistances after the phase winding parallel connection.Because the coil resistance when the coil resistance during electric motor starting move greater than motor, so the electric current of the electric current during electric motor starting when also just being lower than the motor operation, so the utility model can be realized the low current startup of motor.

The utility model advantage is:

The utility model is compared present start-up circuit based on star-triangle start method, only needs two contactors can realize that the low current of motor starts, therefore the manufacturing cost that can save three phase electric machine greatly; And compare at present start-up circuit based on coil sections startup method, it can make coil all participate in electric motor starting, so can avoid coil sections to participate in causing the less than normal and overheated situation of burning of motor torque to take place, improve the fail safe of three phase electric machine operation greatly.

Description of drawings

Below in conjunction with drawings and Examples the utility model is further described:

Fig. 1 is the syndeton schematic diagram of a kind of specific embodiment of start-up circuit described in the utility model;

Fig. 2 is the circuit equivalent structural representation of Fig. 1 embodiment when electric motor starting;

Fig. 3 is the circuit equivalent structural representation of Fig. 1 embodiment when motor moves.

Embodiment

Embodiment: be illustrated in figure 1 as a kind of embodiment of two triangle winding changing-over start-up circuits of the utility model three phase electric machine, it comprises two group of three phase winding and two contactor A, B; Wherein the head end of first, second of first group of three phase winding and

tertiary coil

1,2,3 is connected three phase mains through three reversing switch A1, A2, the A3 of the first contactor A respectively respectively with after first, second end with

tertiary coil

4,5,6 of second group of three phase winding is connected to three contact a, b, c altogether again; Simultaneously the end of first, second of first group of three phase winding and

tertiary coil

1,2,3 is connected on three reversing switch B1, the B2 of the second contactor B, the end of B3 respectively after then being connected to three contact d, e, f altogether with the head end of the 3rd, second and

first coil

6,5,4 of second group of three phase winding respectively, and three reversing switch B1, the B2 of the second contactor B, the other end of B3 then connect three phase mains through three reversing switch A3, A2, the A1 of the first contactor A respectively.

Present embodiment is when electric motor starting, three reversing switch A1, A2, A3 among the first contactor A at first close, this moment first group of three phase winding and second group of three phase winding the first and last end of six

coils

1,6,3,5,2, the 4 big delta-connected circuit of formation that links to each other, its equivalent circuit structure is as shown in Figure 2.This moment, the coil resistance of circuit was equivalent to two resistances after the three-phase windings in series.

And after the motor operation, three reversing switch B1 among the second contactor B again need close, B2, B3, three coils 1 in this moment first group of three phase winding, 2,3 first and last link to each other and form a little delta-connected circuit, three coils 4 in while second group of three phase winding, 5,6 also first and last link to each other to form a little delta-connected circuit, and three coils 1 in first group of three phase winding, 2,3 head end a, b, c respectively with second group of three phase winding 4,5, the head end f of three coils in 6, d, e connects the back altogether and inserts three phase mains, and its equivalent circuit structure as shown in Figure 3.This moment, the coil resistance of circuit was equivalent to two three resistances after the phase winding parallel connection.

Because the coil resistance when the coil resistance during electric motor starting move greater than motor, so the electric current of the electric current during electric motor starting when also just being lower than the motor operation, so present embodiment can be realized the low current startup of motor.

Two triangle winding changing-over start-up circuits of this three phase electric machine that present embodiment provided, compare present start-up circuit based on star-triangle start method, only need two contactor A, B can realize that the low current of motor starts, therefore the manufacturing cost that can save three phase electric machine greatly; And compare at present start-up circuit based on coil sections startup method, it can make coil all participate in electric motor starting, so can avoid coil sections to participate in causing the less than normal and overheated situation of burning of motor torque to take place, improve the fail safe of three phase electric machine operation greatly.

Claims

1. two triangle winding changing-over start-up circuits of a three phase electric machine is characterized in that it comprises two group of three phase winding and two contactors (A, B); Wherein the head end of first, second of first group of three phase winding and tertiary coil (1,2,3) is connected three phase mains through three reversing switches (A1, A2, A3) of first contactor (A) respectively respectively with after first, second end with tertiary coil (4,5,6) of second group of three phase winding is connected to three contacts (a, b, c) altogether again; Simultaneously the end of first, second of first group of three phase winding and tertiary coil (1,2,3) then is connected to an end that is connected on three reversing switches (B1, B2, B3) of second contactor (B) behind three contacts (d, e, f) respectively with the head end of the 3rd, second and first coil (6,5,4) of second group of three phase winding respectively altogether, and the other end of three reversing switches (B1, B2, B3) of second contactor (B) is then respectively through three reversing switches (A3, A2, A1) connection three phase mains of first contactor (A).