CN2038684U

CN2038684U - Universal protector for phase interruption of three-phase asynchronous motor

Info

Publication number: CN2038684U
Application number: CN 88219354
Authority: CN
Inventors: 任永章
Original assignee: JIANGSU POLYTECHNIC COLLEGE
Current assignee: JIANGSU POLYTECHNIC COLLEGE
Priority date: 1988-10-15
Filing date: 1988-10-15
Publication date: 1989-05-31

Abstract

The utility model relates to a universal protector for the phase interruption of a three-phase asynchronous motor. A three-phase zero-sequence transformer B is taken as a sampling element. When the three-phase asynchronous motor is running under the phase interruption of an electrical source, greater imbalance can appear in the three-phase voltage of the input terminal of the three-phase zero-sequence transformer B, so that three-phase composite voltage can be raised rapidly, and a greater value can appear. Accordingly, step signal voltage which is generated suddenly in a zero-sequence winding can propel a relay J to work, so that the normally closed contact of the relay J can be opened, the control circuit of a controlled motor can be cut off, and the purpose of effectively protecting the motor can be obtained. The universal protector for the phase interruption of a three-phase asynchronous motor also has the advantages of good universality and high reliability.

Description

Universal protector for phase interruption of three-phase asynchronous motor

The utility model relates to a kind of threephase asynchronous open phase protection.

Existing threephase asynchronous; adopting with the electric current mostly is the phase failure protector of actuating signal, and this phase failure protector is because the actuating signal current value of different capabilities motor differs greatly; therefore the protector of a certain specification can not adapt to the needs of different capabilities motor, and versatility is relatively poor.Another kind of is the phase failure protector of actuating signal with voltage between outage, is protected placing restrictions on of device and electrical network parallel line scope in practicality, in electrical network protected section shorter, even only can protect one group of fuse.With voltage between zero point is the phase failure protector of actuating signal and since sampled signal voltage a little less than, what tend to voltage between three characteristics of the middle term power supply in the work causes misoperation than large unbalance, reliability is relatively poor.

The purpose of this utility model is that design is a kind of simple, easy row, easy to use, and versatility and the general phase failure protector of all novel preferably threephase asynchronous of reliability.

The general phase failure protector of threephase asynchronous; mainly form by sampling section and protection control section; sampling section adopts three-phase zero sequence transformer B; the protection control section is by rectifier D; capacitor C and direct current relay J form; the input A of three-phase zero sequence transformer B; B; the fiery leading-out terminal that advances of C and motor links; when the threephase asynchronous energized; the voltage relative equilibrium of the three phase mains of three-phase zero sequence transformer B input; the zero sequence winding of three-phase zero sequence transformer B is output as zero; or less voltage signal; when the phase failure of motor power input; the three-phase voltage of three-phase zero sequence transformer input produces than large unbalance; the three-phase resultant voltage is risen rapidly, and the resultant voltage value is bigger, thereby makes the zero sequence winding produce step signal voltage suddenly; step signal voltage is after rectifier D rectification; promote direct current relay J, normally closed interlock is disconnected, cut off the Motor Control loop; controlled motor is had a power failure immediately, protected motor effectively.

Because the utility model is to be sampling element with three-phase zero sequence transformer B, therefore the relation of signal voltage and capacity motor is little, so be not subjected to the influence of the rating of electric machine size during work, versatility is better, link because the input of three-phase zero sequence transformer B directly advances fiery leading-out terminal with three of motor, be not subjected to the influence of electrical network final stage transformer leading-out terminal and motor leading-out terminal discontinuous point position so work.Again owing to sample with three-phase zero sequence transformer; can obtain and the break-point voltage equivalence, and be higher than the signal voltage of three times of voltages between central point, so not only highly sensitive; and avoided the uneven and misoperation that causes of three characteristics of the middle term supply voltage, improved the reliability of phase failure protector.

Description of drawings:

Fig. 1--the general phase failure protector structural representation of threephase asynchronous;

Fig. 2--the general phase failure protector circuit diagram of threephase asynchronous;

Fig. 3--the general phase failure protector circuit diagram of threephase asynchronous;

Fig. 4--zero sequence transformer device structure schematic diagram.

Among Fig. 4: 1.A phase iron core column; 2.B phase iron core column; 3.C phase iron core column; 4. zero sequence iron core column; 5. go up yoke; 6. descend yoke; 7.A phase winding; 8.B phase winding; 9.C phase winding; 10. zero sequence winding; 11. output.

Embodiment:

The general phase failure protector of threephase asynchronous (seeing accompanying drawing 2) sampling section adopts three-phase zero sequence transformer B; the protection control section is by rectifier D; resistor R; capacitor C and relay J are formed; the input A of three-phase zero sequence transformer B; B; the C fiery leading-out terminal that advances direct and motor links; output 11 and the rectifier D of zero sequence transformer B join; rectifier D output connects with direct current relay J; the loading rate of motor when tripping for the ease of adjusting control; be in series with the potentiometer R that adjusts between rectifier D and direct current relay J, capacitor C is in parallel with direct current relay J.Three-phase zero sequence transformer (seeing accompanying drawing 3), form by A, B, C tri-phase iron core post 1,2,3 and winding 7,8,9, last yoke 5, following yoke 6, zero sequence iron core 4 and zero sequence winding 10 respectively, public iron core is to be wound with zero sequence winding 10 on zero sequence iron core 4 and the zero sequence iron core 4.Threephase asynchronous phase failure protector circuit diagram shown in the accompanying drawing 3; sampling section still adopts three-phase zero sequence transformer B; because be that the AC signal that produces when directly utilizing the phase failure promotes relay J work; so the protection control section is only used an AC relay; the loading rate of motor can be in series with resistor during equally for the ease of adjustment control tripping operation between three-phase zero sequence transformer B output 11 and AC relay.

Claims

1, the general phase failure protector of a kind of threephase asynchronous mainly is made up of sampling section and protection control section, it is characterized in that:

A. sampling section adopts three-phase zero sequence transformer B, and the fiery leading-out terminal that advances of input A, B, C and the motor of three-phase zero sequence transformer links, and two of zero sequence coil is an output.

B. protect control section to be made up of rectifier D, capacitor C and direct current relay J, the output 11 and the rectifier D of three-phase zero sequence transformer link, and rectifier D output and direct current relay J link, and capacitor C is in parallel with direct current relay J.

2, the general phase failure protector of threephase asynchronous according to claim 1, the loading rate of motor is in series with resistor when it is characterized in that for the ease of adjustment control tripping operation between rectifier D that protects control section and direct current relay J.

3, the general phase failure protector of threephase asynchronous according to claim 1, when it is characterized in that protecting control section to adopt AC relay J, the output 11 of three-phase zero sequence transformer B directly and AC relay J link.

4, the general phase failure protector of threephase asynchronous according to claim 3 is characterized in that being in series with resistor between three-phase zero sequence transformer B and the AC relay J.