CN2383261Y - Power-off protector for three phase asynchronous motor - Google Patents

Abstract

The utility model provides a power-off protector for a three-phase asynchronous motor. The utility model is composed of a current detection protecting circuit A, a low-voltage starting circuit B, a starting operation control circuit C and an isolating switch QS, wherein, the current detection protecting circuit A, the low-voltage starting circuit B and the starting operation control circuit C are connected in parallel with three phase wires a, b and c of a motor D, and the isolating switch is connected in series with three phase wires a, b and c of the motor. The power-off protector for a three-phase asynchronous motor of the utility model has the characteristics of reasonable design, simple structure, easy manufacture, high safety, easy use, etc.

Description

The threephase asynchronous power-off protector

The utility model relates to a kind of motor safe operation resist technology, specifically a kind of threephase asynchronous power-off protector.

If opening circuit, the phase shortage that threephase motor takes place in running will make motor cause scrapping of equipment because of phase shortage burns out; mostly the various motor protecters of prior art are two-phase protection control; be that control section uses two phase lines or phase line; in use existing deficiency be three-phase power line generation phase shortage and cut off the power supply one mutually just in time not the Be Controlled loop use; control loop can not make three phase lines disconnect immediately to make motor out of service immediately; but by the bimetal leaf expanded by heating of heat sensor the normally-closed contact of thermal relay is disconnected, as thermal relay once operate time long or malfunctioningly can both cause that the motor feels hot burns out.Especially the probability of the threephase asynchronous machine generation phase shortage of using under the work adverse circumstances is maximum, thereby the motor damage is also maximum.

The purpose of this utility model provides three phase lines of a kind of use and provides the threephase asynchronous of power supply power-off protector for controlling back.

The purpose of this utility model realizes in the following manner; in the three-phase electricity of motor, establish and separate the break-make of closing QS control motor triple line and electrical network; when being set the motor phase shortage, current transformer and thermorelay carry out overheated power-off protection on three phase lines of motor; on three phase lines of motor, draw three loops and be connected in series four relays and corresponding single-phase contact switch and three-phase linked contact switch composition motor run switch respectively; motor low voltage starting switch and motor shutdown switch; any phase line outage in three phase lines, corresponding single-phase contact switch just can make the linked contact switch outage that is arranged on three phase lines of motor carry out general protection to motor by control relay.

Accompanying drawing 1 is the electrical block diagram of threephase asynchronous power-off protector;

Accompanying drawing 2 is the schematic block circuit diagram of threephase asynchronous power-off protector.

Explain below with reference to Figure of description threephase asynchronous power-off protector of the present utility model being done.

Threephase asynchronous power-off protector of the present utility model; its structure is to be made of current detecting protective circuit A, low-voltage starting circuit B, startup running control circuit C and isolating switch QS; current detecting protective circuit A, low-voltage starting circuit B and three phase line abc starting running control circuit C and motor D mutually and connect, isolating switch is serially connected on three phase line abc of motor.

Current detecting protective circuit A is by ammeter , current transformer L ₇, L ₈And heat portective switch FR constitutes current transformer L ₈The contact switch J of serial connection thermal protector _-4The back is with ammeter  and meet current transformer L ₇The contact switch J of serial connection thermal protector _-3The back is with ammeter  and connect the termination ground wire of ammeter .

Low-voltage starting circuit B is the coil L by autotransformer ₁, L ₂, L ₃, L ₄, L ₅, L ₆And contact switch J _3-4, J _3-5, and linked switch J _2-3Form coil L ₁End and L ₂First end and connect a phase line of motor D, L ₃End and L ₄Just hold and connect the b phase line of motor D, coil L ₁First end serial connection contact switch J _3-4With coil L ₃First end join coil L ₃First end serial connection contact switch J _3-5With coil L ₅First end join coil L ₂, L ₄, L ₆End serial connection linked switch J _2-3Join with three abc phase lines of motor respectively, its contact is positioned at the operation linked switch J that is serially connected on three abc phase lines of motor D _1-4And on the intermediate connection of isolating switch QS.

Starting running control circuit C is by relay J, relay J ₁, relay J ₂, relay J ₃, push-button switch AN ₁, AN ₂, AN ₃, contact switch J _-1, J-2, J _-5, J _1-1, J _1-2, J _1-3, J _2-1, J _3-1, J _3-2, L _3-3, operation linked switch J _1-4, fuse FU ₁, FU ₂, FU ₃And red green indicator light DL ₁, DL ₂Constitute fuse FU ₁Push-button switch AN ₁, contact switch J ₂, J _3-3, relay J ₁And fuse FU ₃Be serially connected on a and c phase line of motor contact switch J _-5, J _1-3With push-button switch AN ₃And be connected in series relay J, push-button switch AN after connecing again ₂, fuse FU ₂Join contact switch J with motor ab phase line _2-1, J _3-2, relay J ₂Be serially connected between the motor ab phase line push-button switch AN, contact switch J _-1And relay J ₃Be serially connected between the ab phase line of motor contact switch J _1-2, J _3-1And red indicator light DL ₁Be serially connected between the motor ab phase line contact switch J _1-1Green indicator light DL ₂Be serially connected between the motor ab phase line operation linked switch J _1-4Be serially connected on the triple line abc of motor.

Embodiment:

Its processing and fabricating of threephase asynchronous power-off protector of the present utility model is very simple and convenient, and processing and fabricating both can shown in the by specification accompanying drawing.Employed various switching components are general electric product in the circuit, as long as both can use by the circuit diagram installation and processing.

The course of work of threephase asynchronous power-off protector of the present utility model is as follows: the isolating switch QS that closes, three phase lines of motor get electric, red indicator light DL ₁Light.

Motor D start-up course: press the button AN, relay J ₃Get electric self-locking, its normally-closed contact switch J _3-3Disconnect relay J ₃In the time of self-locking, relay J ₂Get electric self-locking, linked switch J _2-3, contact switch J _3-4, J _3-5Closure, the autotransformer energising makes the motor D low voltage starting, and ammeter shows electric current.

Motor D presses the button switch AN after starting steadily ₃, relay J gets electric, normally opened contact switch J _-2Closed self-locking, relay J ₁Get electric self-locking, operation linked switch J _1-4Closure, motor D get electric work, relay J ₁Contact switch J in the time of closed _1-1Closure, green indicator light DL ₂Bright.

Motor D stopped process: press stop button AN ₁, the relay J outage discharges, the running relay J ₁Also outage discharges the motor D stall.

The open-phase protection process of motor D: when a phase line is cut off the power supply, relay J ₁Dead electricity, operation linked contact switch J _1-4Disconnect the motor D stall.

When the b phase line is cut off the power supply, relay J dead electricity, contact switch J _-2Disconnect relay J ₁Dead electricity, linked contact switch J _1-4Disconnect the motor D stall.

When the c phase line is cut off the power supply, relay J ₁Dead electricity, operation linked contact switch J _1-4Disconnect the motor D stall.

Threephase asynchronous power-off protector of the present utility model is compared with prior art, have reasonable in design, simple in structure, be easy to processing, characteristics such as safe and reliable, easy to use, thereby, have good value for applications.

Except that the described technical characterictic of specification, be the known technology of those skilled in the art.

Claims (4)

1. threephase asynchronous power-off protector; comprise current detecting protective circuit A, low-voltage starting circuit B, start running control circuit C and isolating switch QS; three phase line abc that it is characterized in that current detecting protective circuit A, low-voltage starting circuit B and start running control circuit C and motor D mutually and connect, isolating switch is serially connected on three phase line abc of motor.

2. threephase asynchronous power-off protector according to claim 1 is characterized in that current detecting protective circuit A is by ammeter , current transformer L ₇, L ₈And heat portective switch FR constitutes current transformer L ₈The contact switch J of serial connection thermal protector _-4The back is with ammeter  and meet current transformer L ₇The contact switch J of serial connection thermal protector _-3The back is with ammeter  and connect the termination ground wire of ammeter .

3. threephase asynchronous power-off protector according to claim 1 is characterized in that low-voltage starting circuit B is the coil L by autotransformer ₁, L ₂, L ₃, L ₄, L ₅, L ₆And contact switch J _3-4, J _3-5, and linked switch J _2-3Form coil L ₁End and L ₂First end and connect a phase line of motor D, L ₃End and L ₄Just hold and connect the b phase line of motor D, coil L ₁First end serial connection contact switch J _3-4With coil L ₃First end join coil L ₃First end serial connection contact switch J _3-5With coil L ₅First end join coil L ₂, L ₄, L ₆End serial connection linked switch J _2-3Join with three abc phase lines of motor respectively, its contact is positioned at the operation linked switch J that is serially connected on three abc phase lines of motor D _1-4And on the intermediate connection of isolating switch QS.

4. threephase asynchronous power-off protector according to claim 1, it is characterized in that starting running control circuit C is by relay J, relay J ₁, relay J ₂, relay J ₃, push-button switch AN ₁, AN ₂, AN ₃, contact switch J _-1, J _-2, J _-5, J _1-1, J _1-2, J _1-3, J _2-1, J _3-1, J _3-2, L _3-3, operation linked switch J _1-4, fuse FU ₁, FU ₂, FU ₃And red green indicator light DL ₁, DL ₂Constitute fuse FU ₁Push-button switch AN ₁, contact switch J ₂, J _3-3, relay J ₁And fuse FU ₃Be serially connected on a and c phase line of motor contact switch J _-5, J _1-3With push-button switch AN ₃And be connected in series relay J, push-button switch AN after connecing again ₂, fuse FU ₂Join contact switch J with motor ab phase line _2-1, J _3-2, relay J ₂Be serially connected between the motor ab phase line push-button switch AN, contact switch J _-1And relay J ₃Be serially connected between the ab phase line of motor contact switch J _1-2, J _3-1And red indicator light DL ₁Be serially connected between the motor ab phase line contact switch J _1-1Green indicator light DL ₂Be serially connected between the motor ab phase line operation linked switch J _1-4Be serially connected on the triple line abc of motor.