CN2039084U

CN2039084U - One-way start controlling box of a three-phase ac motor

Info

Publication number: CN2039084U
Application number: CN 88215765
Authority: CN
Inventors: 李玉梅; 王德明; 李顺枝
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-11-11
Filing date: 1988-11-11
Publication date: 1989-06-07

Abstract

The utility model discloses a one-way start controlling box of a three-phase AC motor and relates to the field of control equipment of a motor. The one-way start controlling box of a three-phase AC motor comprises a box body, and a starting control part of a motor arranged on the box body. The one-way start controlling box of a three-phase AC motor is characterized in that an asymmetrical star load is arranged on a three-phase power supply. The load is composed of a capacitance and two alternating current contactors. Three pairs of main contacts of the contactors are connected in series and are inversely connected in a main circuit, which changes the phase-sequence of the three-phase voltage. Therefore, the motor can be started uniaxially no matter how a power cord is introduced. The utility model has the advantages of simple structure and high reliability. The one-way start controlling box of a three-phase AC motor is especially suitable for the motor of a mobile device or the equipment with reversing rotation which does not need a motor.

Description

One-way start controlling box of a three-phase AC motor

The utility model belongs to the control appliance of motor

Three phase alternating current motor is widely used in all trades and professions, and the starting control cabinet of present existing three phase alternating current motor is behind power connection, motor can drive, and as power line paraphase position, motor is with regard to fail to start, at this moment, the wiring paraphase of power line just can must be made electric motor starting.Therefore, for roving equipment, whenever mobile primary equipment, will before wiring, predict the phase place of three-phase power line, perhaps first wiring experimental starting, as not rotating, line falling is nose heave again connects, and obviously is very inconvenient like this, and the end of a thread also disconnects tired easily back and forth and fractures, very uneconomical, work efficiency is also low.

The purpose of this utility model is the unidirectional starting control cabinet of a kind of new three phase alternating current motor of design, and it can realize automatic commutation, also promptly how to introduce regardless of power line, always this control cabinet can make the unidirectional starting of three phase alternating current motor.Thereby use convenient greatly, work efficiency height, and the loose contact that causes of can avoiding fractureing because of taking out stitches back and forth makes the disadvantage of motor damage.

The principle that the neutral point displacement of asymmetric star load changes the phase sequence of load phase voltage in the utility model application principles of electric and electronic engineering, three phase mains A at three phase alternating current motor, B, among the C, insert an electric loading respectively, the big inductive load of two ac contactor coils, to form asymmetric star load, so that this star neutral point displacement, the phase sequence of load phase voltage is changed to some extent, make the phase sequence of some power lines in the inductive load that the A.C. contactor that is connected in it is connected earlier, by the connection of contacts of contactor in main control circuit, just can reach the purpose of automatic adjustment three-phase alternating-current supply, thereby the folk prescription that has guaranteed motor is to startup.

Embodiment

Fig. 1 is electric control theory figure of the present utility model

Fig. 2 is the utility model card layout plan

Fig. 3 is the utility model case face layout plan

As shown in Figure 1, by control cabinet casing, interchange contact 3C, button QA, TA, thermal relay JR, three phase mains air switch ZK, fuse RD, signal lamp LD, HD, the motor main circuit of forming and control loop, the utility model is on three-phase power line A, B, C, connect an asymmetric star load, its A capacitor C of joining, B, C respectively are connected in series coil 1C, the 2C of an A.C. contactor mutually, again the two ends of capacitor C and the auxiliary normally opened contact of contactor are in parallel, at coil 2C and the C normally-closed contact 1C of string one contactor 1C between power supply mutually ₂, at coil 1C and the B normally-closed contact 2C of string one contactor 2C between power supply mutually ₂, the main contacts of in major loop, connect 1C, 2C, and the B of 2C, the mutual anti-series of C phase main contacts.When among three-phase power supply phase sequence A, B, C and the figure mark when consistent, B phase current potential leading is in the C phase, 1C adhesive, 1C ₁Connect 1C ₂Disconnect, 2C outage, and capacitor C short circuit, motor rotates along positive direction; If the AC power phase sequence becomes A, C, B, this moment C phase current potential leading in the B phase, 2C adhesive, 2C ₁Connect 2C ₂Disconnect, the 1C outage, the capacitor C short circuit because the main contacts of 2C is played a reversed role mutually mutually at B, C, makes phase sequence fall into A, B, C automatically in the major loop, and motor still rotates along positive direction, thereby plays the effect of automatic commutation.

Fig. 2 is the card layout plan of this control cabinet, and 1C, 2C, 3C are for exchanging the A.C. contactor of 380V among the figure, and ZK is that the three-phase air is made automatically, and RD is a fuse, and C is the 600V oiled paper capacitor, and JD is a binding post.

Fig. 3 is the case face layout plan of control cabinet, and button QA, TA and signal lamp LD, HD all are loaded on card as seen from the figure, so that operate and learn the motor rotation state.

The utility model does not allow equipment reverse rotation, frequent shift position that great convenience is provided for using the many of three phase alternating current motor, and used element seldom, and guarantee unidirectional rotation, dependable performance, circuit is simple, also can improve the consumption of work efficiency and minimizing electric wire, good practical value is arranged, it is roving then more suitable that the utility model especially needs again for the squirrel-cage motor that directly starts below 10 kilowatts.

Claims

1, the unidirectional starting control cabinet of three phase alternating current motor, it comprises casing, be loaded on the major loop electric control system of being made up of air switch ZK, A.C. contactor 3C, thermal relay JR, fuse RD, button, signal lamp on the casing, it is characterized in that being provided with one be connected on that the phase sequence that can make phase voltage on the three phase mains changes, by an electric loading and two asymmetric star loads that ac contactor coil 1C, 2C form, and this two contactor often open the attached contact 1C that helps ₁, 2C ₁Be in parallel normally closed interlock 1C with electric loading ₂, 2C ₂Connect with its coil 2C, 1C interlocking, 3 pairs of main contacts are connected in major loop, and two-phase is played a reversed role mutually and connect in two main contacts of contactor 2C and the power line.

2, by the unidirectional starting control cabinet of the described three phase alternating current motor of claim 1, it is characterized in that an electric loading in the described asymmetric star load is a capacitive load.