CN2158149Y - Passive three-phase protector for motor - Google Patents

Abstract

The utility model relates to a passive three-phase protector for a motor, which is provided with a protective circuit for overload, short circuit and phase failure, and the utility model is composed of an I/U conversion circuit, a checking circuit for phase failure, a sampling circuit for overload, a delay time buffering circuit for overload, a starting delay time circuit and a driving executive circuit. The voltage induced by the passive three-phase protector for a motor from the electric current of a three phase power supply via a mutual inductor is served as the working voltage and the detection signals of a whole circuit after the rectification of a diode; then, the detection signals are sent to the driving executive circuit via a simulation nand gate. The utility model has the advantages of work reliability, energy saving, small size, simple structure, convenient manufacture, convenient installation, convenient operation, etc.; the utility model can protect a motor from burning.

Description

Passive three-phase protector for motor

The utility model relates to the control of electrical equipment field, and particularly a kind of threephase motor that is used for occurs under overload, the phase failure, the short-circuit conditions, and the passive threephase motor protector of reliably protecting effect is all arranged.

As everyone knows; in existing various motor protectors; according to itself needs power supply electric power thus supplied whether; it can be reduced two big classes: a class is the active motor protector of using morely at present; not only volume is big for it, and cost height, performance are unreliable, and will consume the nearly myriawatt/platform of electric power in 1 year; and the time have accident to take place, cause motor to burn and other mechanical breakdown.

Another kind of is passive motor protector, its objective is to wish to overcome above-mentioned defective.For example, China's No. 90224886.3 patent application documents disclosed a kind of " non-transformer solid-state relay " promptly belong to this type of.But, by technical scheme that this patent documentation provided as can be known, because of it has adopted five one-way SCRs and the higher element of price such as bidirectional triode thyristor, so be unfavorable for reducing the separate unit product cost.In addition, what deserves to be mentioned is, run counter to the controllable silicon principle because of its circuit design, promptly controlled the utmost point, must add positive and negative pulse respectively in conducting, when ending, or whole power supply disappearance just can reach by purpose, and also have pressure drop about 1 volt during its bidirectional triode thyristor conducting, to the efficient influence of A.C. contactor CJ, send undersuing when not adopting this controllable silicon is ended to the phase failure, overload, short circuit, so CJ can not stop adhesive automatically.Call by name and talk about, can take place still that motor burns and other mechanical breakdown problem.

The purpose of this utility model is at the problems referred to above; a kind of improved passive threephase motor protector is provided; when overload, short circuit and three kinds of situations of the phase failure appear in three phase electric machine, all can implement defencive function in time, reliably, thereby stop burn-down of electric motor and the generation of other mechanical breakdown.

The purpose of this utility model is achieved in that and is provided with overload, short circuit and open-phase protection circuit in its housing; this protective circuit is cushioned, starts time-delay and driven executive circuit by I/U conversion, phase failure detection, overload sampling, overload time-delay to be formed; the instrument transformer of the I/U conversion that its employing iron core is made; the induction by current of three phase mains is gone out voltage; after rectifies; make the operating voltage and the detection signal of entire circuit respectively, this signal is sent to drive circuit through the simulation NAND gate again and carries out.

Above-mentioned I/U translation circuit can have two kinds of versions: a kind of is to comprise 2 instrument transformers and 6 rectifier diodes, and another kind is to comprise 3 instrument transformers and 9 rectifier diodes.Why adopting the fabrication of iron core instrument transformer, is in order to improve the conversion efficiency of I/U, and instrument transformer can have 1 or 2 windings, is respectively threading type and Wiring type, and the former is suitable for heavy-duty motor, and the latter is suitable for low-power machine.

Above-mentioned overload sample circuit can be made up of 1 adjustable potentiometer and voltage-stabiliser tube.For the ease of the use of different capacity motor, can set up 1 overload sampling value by-pass cock that is connected with adjustable potentiometer, switch is made up of the series resistor more than 2 or 2.

Above-mentioned overload time-delay, startup time-delay and driving executive circuit design in order to guarantee motor normally to start, move and protect.

The utility model is owing to having adopted above reasonably circuit structure, so following advantage is arranged:

One, reliable operation, protection is active in one's movements, and can avoid taking place burn-down of electric motor and other mechanical breakdown.

Two, simple in structure, volume is little, is convenient to making, installation and with low cost.

Three, energy-conservation, itself do not need the power supply of extraneous power supply.

Four, easy to use, the scene need not debugging, can directly use according to power of motor, and wiring is simple.

Fig. 1 is a circuit block diagram of the present utility model.

Fig. 2 is the physical circuit schematic diagram of Fig. 1.

Fig. 3 and Fig. 4 are two kinds of shell mechanism schematic diagrames of the utility model.

Fig. 5 is Fig. 3 and Fig. 4 wiring schematic diagram in electric wiring.

The utility model is described in further detail below in conjunction with drawings and Examples.

As shown in Figure 1, the utility model is cushioned, starts time-delay and driven executive circuit by I/U conversion, phase failure detection, overload sampling, overload time-delay and forms.

As shown in Figure 2, the I/U translation circuit is three instrument transformers (T1, T2, T3) and nine the rectifier diode (VD1～VD9) form that adopt fabrication of iron core.Its annexation is: VD1 and VD2 positive pole and VD3 negative pole, VD4 and VD5 positive pole and VD6 negative pole, VD7 and VD8 positive pole and VD9 negative pole are connected to the non-ground-end of the induction coil of T1, T2, T3 respectively.VD1, VD4, VD7 negative pole are connected to the positive terminal of capacitor C 1, C2, C3, C4 and C6.The VD1 negative pole connects triode V1, V2, V3 emitter.V1, V2, V3 collector electrode link to each other.C1, C2, C3 negative pole connect the base stage of V1, V2, V3 and VD2, VD5, VD8 negative pole respectively.VD3, VD6, VD9 positive pole are connected to the C5 negative pole end, are in order to provide bias voltage to V1, V2, V3, and form the simulation NAND gate respectively after R1, R2, R3 connect V1, V2, V3 base stage.Above-mentioned V1, V2, V3, R1, R2, R3 and C1, C2, C3 then form open-phase detection circuit.C5 positive pole, C4 minus earth.

In the above-mentioned I/U translation circuit, any 1 instrument transformer wherein and three diodes and 1 resistance, electric capacity and the triode that is attached thereto can be saved (for example saving T3, VD7, VD8, VD9, R3, C3, V3).If the power line phase failure of the associated of saving is therewith just then handled as overload by the instrument transformer that does not save, reach protection motor purpose.Specifically, this circuit is made up of instrument transformer T1, T2 and rectifier diode VD1～VD6.Wherein, the positive pole of the positive pole of VD1 and VD2 and VD3 negative pole, VD4 and VD5 and VD6 negative pole are connected to the non-ground-end of the induction coil of T1, T2 respectively.VD1, VD4 negative pole are connected to C1, C2, C4, C6 positive terminal.The VD1 negative pole connects V1, V2 emitter.V1, V2 collector electrode link to each other.C1, C2 negative pole connect V1, V2 base stage and VD2, VD5 negative pole respectively.VD3, VD6 positive pole are connected to the C5 negative pole end and form the simulation NAND gate respectively after R1, R2 connect V1, V2 base stage, and two triode, resistance and C1, C2 form open-phase detection circuit.

The overload sample circuit is made up of adjustable potentiometer RP1 and voltage-stabiliser tube DW.The DW negative pole connects the RP1 central contact.The DW positive pole connects V7 base stage, V8 collector electrode and C7 positive pole, and connects the V7 collector electrode by R6 ground connection, R8.RP1 is two ends in addition, an end ground connection, another termination V1, V2, V3, V6 emitter.Dotted portion is overload sampling value by-pass cock among the figure.The moved end b2 of switch meets RP1 central contact b2, and the high and low end of switch connects respectively in addition two ends of RP1 (b1, b2).Switch is made up of 8 series resistors, can adapt to 8 kinds of different capacity motors and use.Save this switch, then this circuit only is applicable to that a kind of power motor uses.

Overload time-delay buffer circuit is made up of V6, V7, V8, R6, R7, R8, R9, C7, C8 and VD13.Wherein the V6 base stage connects V7 collector electrode, VD11 negative pole through R8, and the V6 collector electrode connects V7 base stage, V8 collector electrode, R6, C7 positive pole through R7.The C8 positive pole connects V6, V1, V2, V3 emitter.The C8 negative pole meets VD13 negative pole, R9.Another termination of R9 V8 base stage.V7, V8 emitter and VD13 positive pole are connected to ground.VD11 plays buffer action, and its positive pole connects C2 negative pole, V2 base stage.

Start delay circuit, form by V4, R4, C6 and VD10.Wherein, the V4 base stage connects C6, VD10 negative pole through R4.V4 emitter, VD10 plus earth.The V4 collector electrode connects the V5 base stage and connects the V1 collector electrode through isolation resistance R5.

Driving executive circuit is made up of V5, VD12, relay K, R12, C9.Wherein, the V5 collector electrode connects coil, the VD12 positive pole of K.Another termination of the coil of K VD12 negative pole, C6 positive pole.The normally-closed contact two ends of K are connected to R12, the C9 of series connection.

Also shown light-emitting diode among Fig. 1 by V9 relay indicating light LED(), the working point formed of R10, R11 and RP2 sets up and indicating circuit.Three instrument transformer T1, T2, T3 can be provided with 1 winding (solid line among the figure) or 2 windings (real, dotted line among the figure), use to be applicable to the motor more than the 5KW or below the 5KW respectively.Y1, the Y2 of Fig. 5 seen in their wiring in electric wiring, is respectively threading type and Wiring type.The structure of both shells 2 respectively as shown in Figure 3, Figure 4.

As shown in Figure 3: on the shell 2 of Y1, be provided with the sub-1(in control output end and be X1, X2 in the circuit), 3 power line perforation 3(are positioned at the top or the bottom of shell 2) and 1 relay indicating light LED.The size of shell 2 can be 90 * 70 * 25mm.

As shown in Figure 4, on the shell 2 of Y2, be provided with 9 notches, the sub-1(in control output end be set be X1, X2 in the circuit in two notches in the left side), in 6 notches in the right is respectively that three power supplys are represented with A1, B1, C1 and A2, B2, C2 into and out of binding post 5(), also be provided with LED.The size of shell 2 can be 90 * 70 * 25mm.

As shown in Figure 5: the sub-X1 in the control output end of Y1, Y2, X2 are connected to the normally-closed contact two ends of relay K respectively.Three-phase power line A, B, C pass the hole 3 of Y1.The contact that the electric power incoming line terminal A1 of Y2, B1, C1 meet A.C. contactor CJ respectively, power outlet terminal A2, B2, C2 then link to each other with the power line of motor D.RD is a fuse.TA, QA start, stop button.The housing of CJ and Y1 or Y2 all is contained on the fixed head 4.

Operation principle of the present utility model is: T1, T2, T3 by VD1, VD4, VD7 rectification, through C4 filtering, are the operating voltage U of whole protecting circuit after the induction by current of three-phase power line (A, B, C) is gone out three-phase signal voltage; Be shaped as direct current signal UA, UB, UC by VD2, VD5, VD8, make it to end after entering V1, V2, V3 base stage; After VD3, VD6, VD9 rectification, be filtered into negative pressure through C5, make V1, V2, V3 base stage provide reliable negative bias when certain phase power supply phase failure, thereby make certain pipe of V1, V2, V3 enter the saturation region rapidly by R1, R2, R3.In fact, the connection of this circuit has formed the NAND gate circuit of simulation.RP1, RP2 for shut down or action protection after to the discharge resistance of C4.C6, R4 and V4 are that RC starts delay circuit, allow U normally set up rapidly when being used to start.VD10 is the C6 repid discharge and makes restarting and prepare.The base stage of V5 and V4 collector electrode are connected by R5 and V1, V2, V3 collector electrode, and U voltage is also set up rapidly when having prevented that the phase failure from starting.R4, C6, V4 set up the delay protection circuit for U voltage, are used for the phase failure and start.V6, V7 and R7, R8 form the ghyristor circuit form that is similar to.RP1 is for adjusting overload values, and threshold values is become in the emission of DW and V6, when overload; when U voltage rises to a certain value (U overload values) DW+V6Ubeo); the V6 conducting makes V6, V7 pipe sharply saturated, by VD11 arbitrary base potential of V1, V2, V3 is dragged down the formation overload protection.V8, R9, C8 are the roads for RC time-delay also, and when mainly solving big current start, U voltage can substantially exceed the value of DW+V6Ubeo, adopt C8, R9 and V8 to form to start, the overload delay circuit, and VD13 is that C8 does repid discharge equally, performs the restarting time-delay and prepares.C7 prevents that mainly overload plays cushioning effect suddenly, has good anti-time limit characteristic.R12, C9 are that protection relay plays the antispark effect, prolong the useful life of relay K contact.The LED light-emitting diode is subjected to the control of V9 to indicate this circuit whether to set up the normal value of U through the step-down of R11 current limliting, and V9 is determined the value working properly of U by the adjustment of RP2 by R10.

The brief description concrete course of work of the present utility model once: arbitrary phase failure phenomenon 1. has been in operation, then this mutually non-inductive voltage input, V1, V2, V3 wherein have a pipe to be in saturation condition, make the saturated and driving relay K action of V5, CJ A.C. contactor thereby lose voltage and discharge, motor D is out of service.When 2. being in operation the overload phenomenon, the U that induces can increase severely and surpass sampling value, makes V6, V7 conducting, impels the V3 pipe to enter the saturation region, the saturated and driving relay K action of V5.Thereby make the not reason phase failure of motor, overload and burn, reached the purpose of protection motor.

Claims (10)

1, a kind of passive threephase motor protector; its shell is provided with overload, short circuit and open-phase protection circuit in (2); it is characterized in that described protective circuit is detected, overload sampling, overload time-delay buffering, started time-delay, drives executive circuit and form by I/U conversion, the phase failure; it adopts iron core to make the instrument transformer of I/U conversion; the induction by current of three phase mains is gone out voltage; after rectifies; respectively as the operating voltage and the detection signal of entire circuit; this signal is sent to drive circuit and carries out through the simulation NAND gate.

2; according to power 1 described motor protector; it is characterized in that in the I/U translation circuit; be provided with instrument transformer T1; T2 and rectifier diode VD1～VD6 forms; wherein; the positive pole of VD1 and VD2 and VD3 negative pole; the positive pole of VD4 and VD5 and VD6 negative pole; be connected to T1 respectively; the non-ground-end of the induction coil of T2; VD1; the VD4 negative pole is connected to C1; C2; C4; the C6 positive terminal; the VD1 negative pole meets V1; the V2 emitter; V1; the V2 collector electrode links to each other; C1; the C2 negative pole meets V1 respectively; V2 base stage and VD2; the VD5 negative pole; VD3; the VD6 positive pole is connected to the C5 negative pole end and respectively through R1; R2 meets V1; form the simulation NAND gate after the V2 base stage, two triodes; resistance and C1; C2 forms open-phase detection circuit.

3; according to power 1 described motor protector; it is characterized in that in the I/U translation circuit; be provided with instrument transformer T1; T2; T3 and rectifier diode VD1～VD9 forms; wherein; the positive pole of VD1 and VD2 and VD3 negative pole; VD4 and VD5 positive pole and VD6 negative pole; VD7 and VD8 positive pole and VD9 negative pole; be connected to T1 respectively; T2; the non-ground-end of the induction coil of T3; VD1; VD4; the VD7 negative pole is connected to C1; C2; C3; C4; the C6 positive terminal; the VD1 negative pole meets V1; V2; the V3 emitter; V1; V2; the V3 collector electrode links to each other; C1; C2; the C3 negative pole meets V1 respectively; V2; V3 base stage and VD2; VD5; the VD8 negative pole; VD3; VD6; the VD9 positive pole is connected to the C5 negative pole end and respectively through R1; R2; R3 meets V1; V2; form the simulation NAND gate after the V3 base stage, by three triodes; resistance and C1; C2; C3 forms open-phase detection circuit.

4, motor protector according to claim 1; the sample circuit that it is characterized in that transshipping is made up of adjustable potentiometer RP1 and voltage-stabiliser tube DW; the DW negative pole connects the RP1 central contact; the DW positive pole connects V7 base stage, V8 collector electrode and C7 positive pole; and connect the V7 collector electrode by R6 ground connection, R8; RP1 is two ends in addition, an end ground connection, a termination V1, V2, V3, V6 emitter.

5, according to power 4 described motor protectors; it is characterized in that RP1 links to each other with the overload sampling value by-pass cock of being made up of the serial connection fixed resistance more than 2 or 2; wherein; the central contact of RP1 (b2) connects the moved end (b2) of switch, and the high and low end span of switch is connected in addition two ends of RP1 (b1, b2).

6, according to power 1 described motor protector; it is characterized in that overload time-delay buffer circuit; form by V6, V7, V8, R6, R7, R8, R9, C7, C8 and VD13; wherein; the V6 base stage connects V7 collector electrode, VD11 negative pole through R8, and the V6 collector electrode connects V7 base stage, V8 collector electrode, R6, C7 positive pole through R7, and the C8 positive pole connects V6, V1, V2, V3 emitter; the C8 negative pole connects VD13 negative pole, another termination of R9, R9 V8 base stage, and V7, V8 emitter and VD13 positive pole are connected to ground.

7, according to power 1 described motor protector, it is characterized in that starting delay circuit, form by V4, R4, C6 and VD10; wherein; the V4 base stage connects C6, VD10 negative pole through R4, V4 emitter, VD10 plus earth, and the V4 collector electrode connects the V5 base stage and connects the V1 collector electrode through isolation resistance R5.

8, according to power 1 described motor protector; it is characterized in that driving executive circuit is made up of V5, VD12, relay K, R12, C9; wherein; the V5 collector electrode connects coil, the VD12 positive pole of K; another termination of the coil of K VD12 negative pole, C6 positive pole, the normally-closed contact two ends of K also are connected to R12, the C9 of series connection.

9, according to power 1 described motor protector, it is characterized in that T1, T2, T3 are provided with 1～2 winding.

10, according to power 1 described motor protector; the size that it is characterized in that shell (2) is 90 * 70 * 25mm; housing is provided with control output end (1) that is connected with relay K; relay indicating light LED and 3 the power lines perforation (3) that are positioned at housing top or bottom; perhaps; be provided with control output end (1), the power supply turnover binding post (5) that link to each other with K in the notch of its housing, on this housing LED be housed.

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