CN2308193Y

CN2308193Y - Electric motor protector

Info

Publication number: CN2308193Y
Application number: CN 97239762
Authority: CN
Inventors: 张安定
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-06-25
Filing date: 1997-06-25
Publication date: 1999-02-17
Anticipated expiration: 2007-06-25

Abstract

The utility model relates to a protector for electric motors. The utility model is composed of a power supply circuit, a voltage stabilizing circuit, a delay circuit and a switch control circuit. The power supply circuit adopts a transformer with large aperture to supply the working source and the actuating signal source for the protector of the electric motor. The switch control circuit adopts a miniature relay and a bidirectional thyristor. The bidirectional thyristor controls the electric motor to act. The utility model is additionally provided with a regulation, running and protection circuit which is used for regulating the working conditions of the electric motors with different powers when in running. The utility model has strong self protection ability, does work and one-time protection and has no resetting on the over current of the electric motor caused by various reasons, and the utility model has the advantages of reliability, stability and strong anti-interference ability.

Description

Motor protector

The utility model belongs to technical field of electricity, relates in particular to a kind of running protection device of motor.

Existing motor protector, generally by power circuit, voltage stabilizing circuit, delay circuit, signal source circuit and ON-OFF control circuit are formed, power circuit is by supplying with motor protector after the transformer transformation as working power, again through voltage stabilizing circuit, delay circuit is sent into signal source circuit, signal source circuit is to make signal source by high-frequency induction, do to amplify sampling by integrated circuit, send into ON-OFF control circuit then, because power circuit adopts transformer to make power supply, make motor when the overcurrent acting that causes because of a variety of causes, transformer is easily burnt out, and causes the self-insurance ability of protector relatively poor; Signal source circuit adopts high-frequency induction and integrated circuit to amplify sampling; also make this circuit be unable to undergo the impact of big electric current; cause the damage of integrated circuit: the switch that in ON-OFF control circuit, only adopts control relay circuit; have the contact easy-sintering and move problem such as insensitive, these all make the operation that motor protector can not be reliable and stable.

The purpose of this utility model is to provide a kind of self-insurance ability strong and motor protector that can reliable and stable operation

For achieving the above object; provide technical scheme as follows: motor protector contains power circuit, voltage stabilizing circuit, delay circuit and ON-OFF control circuit; power circuit is after the voltage stabilizing circuit voltage stabilizing; be connected with delay circuit; delay circuit is connected with ON-OFF control circuit; form by three large aperture instrument transformers particularly in power circuit; three phase lines of motor pass therethrough respectively; power circuit is again through a current rectifying and wave filtering circuit; be connected with voltage stabilizing circuit, current rectifying and wave filtering circuit is made up of three Qiao Dui and an electric capacity.

The ON-OFF control circuit of motor protector is made up of midget relay and bidirectional triode thyristor.In addition, set up adjusting running protection circuit, be made up of adjustable potentiometer and ammeter, this circuit is connected with ON-OFF control circuit with current rectifying and wave filtering circuit.

This motor protector; the power circuit of its power circuit and existing protector has significant difference; it adopts the large aperture instrument transformer to form; three phase lines of motor are by passing in the instrument transformer; secondary terminals at instrument transformer promptly produces induced voltage; provide operation source with this to protector, pitch simultaneously, send into voltage stabilizing circuit through rectifying and wave-filtering then to protector provides the actuating signal source.This power circuit has overcome the shortcoming that transformer is easily burnt out in original power circuit, owing to saved signal source circuit, has also overcome the not impact-resistant defective of integrated circuit in the signal source circuit.This protector does not have voltage to select, and has only electric current to select, and therefore has very strong self-insurance ability.ON-OFF control circuit has overcome the insensitive shortcoming of action that original ON-OFF control circuit repeat circuit contact easy-sintering is produced by the shutdown of bidirectional triode thyristor control motor.This motor protector can be done disposable protection to the excessive current flow in motor acting that causes because of a variety of causes, never resets, and has remedied the deficiency of original protector aspect open-phase protection.

Below in conjunction with the embodiment accompanying drawing the utility model is described in further detail.

Fig. 1 is the functional-block diagram of motor protector.

Fig. 2 is the circuit diagram that motor protector is connected with motor.

Fig. 1 shows the part of motor protector, it is made up of power circuit, current rectifying and wave filtering circuit, voltage stabilizing circuit, delay circuit, ON-OFF control circuit, power circuit connects current rectifying and wave filtering circuit, current rectifying and wave filtering circuit connects voltage stabilizing circuit, voltage stabilizing circuit connects delay circuit, and delay circuit connects ON-OFF control circuit; In addition, also have one to regulate the running protection circuit, it is connected with ON-OFF control circuit with current rectifying and wave filtering circuit.Power circuit provides operation source and actuating signal source for motor protector, and this is the remarkable difference of the utility model and original motor protector.

Among Fig. 2, the with dashed lines frame has gone out each part of motor, and I is a power circuit, and II is a current rectifying and wave filtering circuit, and III is a voltage stabilizing circuit, and IV is a delay circuit, and V is an ON-OFF control circuit, and VI regulates the running protection circuit.Power circuit adopts integrated large aperture mutual inductance circuit to do operation source and actuating signal source, and it is by three large aperture instrument transformer K ₁, K ₂, K ₃Form, three phase lines of motor D are respectively by the cable-through hole on the instrument transformer of large aperture, and the secondary terminals generation induced voltage at instrument transformer provides operation source with this to protector.Because motor all is reflected in three phase lines of motor because of the electric current that a variety of causes causes changes, this variation is reflected in the power circuit by instrument transformer again, thereby provides the actuating signal source to protector.Instrument transformer K ₁Secondary terminals be 1,2, K ₂Secondary terminals be 3,4, K ₃Secondary terminals be 5,6.The signal of coming from power circuit just can enter voltage stabilizing circuit through behind the rectifying and wave-filtering, and current rectifying and wave filtering circuit is by three bridge heap Q ₁, Q ₂, Q ₃And capacitor C ₁Form, the end of incoming cables of three bridge heaps is followed successively by 10,20,30,40,50,60.They respectively with K ₁, K ₂, K ₃Corresponding connection of secondary terminals 1,2,3,4,5,6, the leading-out terminal of three bridge heaps all is connected capacitor C ₁Two ends.Voltage stabilizing circuit is by three-port variable voltage regulator LM ₃₁₇And resistance R ₁, R ₂Form the impact that to bear motor starting electric current under identical protection power reliably.Delay circuit is by one-way SCR MCR, capacitor C ₂And resistance R ₃, R ₄Form, during motor starting, three-port variable voltage regulator LM ₃₁₇Output pass through R ₃Give capacitor C ₂One-way SCR MCR conducting in the time of setting is being preset in charging, and motor is in normal operating state, has removed the setting of original protector machine external delay time from.ON-OFF control circuit is made up of midget relay JG and bidirectional triode thyristor MRC, and this circuit is connected with motor switch control circuit cashier's office in a shop, promptly by the starting stop button H on the bidirectional triode thyristor MRC connection switch cubicle ₁, H ₂, when excessive current flow in motor; midget relay JG action is opened a way the trigger electrode of bidirectional triode thyristor MRC and the control circuit on the switch cubicle, and at this moment bidirectional triode thyristor MRC changes closed condition into by conducting state; cause motor switch control circuit cashier's office in a shop to have a power failure, motor is protected.Regulate the running protection circuit by adjustable potentiometer R ₅Form with ammeter A, this circuit is connected between current rectifying and wave filtering circuit and the ON-OFF control circuit, and ON-OFF control circuit is controlled.Because what regulate that the row protective circuit adopts is the choked flow form, no electronics amplifier element has so just solved the problem of the anti-High-frequency Interference poor stability that existing protector employing amplifier brings as running protection.

The course of work of motor protector is as follows: will pass the instrument transformer cable-through hole of three phase lines of motor from motor protector earlier during wiring, protector is connected with control circuit on the switch cubicle again, regulate adjustable potentiometer R then ₅To maximum, press the starting stop button after, instrument transformer K ₁, K ₂, K ₃To the protector power supply, behind rectifying and wave-filtering, pressurizer LM ₃₁₇With capacitor C ₂MCR starts to one-way SCR, the time-delay conducting, and midget relay JG is synchronoused working with adjusting running protection circuit with bidirectional triode thyristor MRC, and regulate adjustable potentiometer R according to the actual indication on the ammeter this moment ₅Current Regulation is got final product in the protection service area; when irregular working appears in motor; when causing electric current excessive; ammeter indication enters overload region, at this moment ON-OFF control circuit promptly to switch cashier's office in a shop the voltage of control circuit block, make the pull-in winding decompression of A.C. contactor L in the control circuit; contactor disconnects, motor quits work, thereby protected motor.This protector is to carrying out reliable protection because of the motor that opens circuit, move under the situation such as under-voltage, short circuit, overload, phase shortage; Especially to cause the situation of three-phase imbalance because of partial high pressure circuit phase shortage, play protection timely, remedied the deficiency of original protector aspect open-phase protection.Have the characteristics stable, reliable, that antijamming capability is strong.

Claims

1, motor protector contains power circuit, voltage stabilizing circuit, delay circuit and ON-OFF control circuit; power circuit is after the voltage stabilizing circuit voltage stabilizing; be connected with delay circuit; delay circuit is connected with ON-OFF control circuit; it is characterized in that power circuit is made up of three large aperture instrument transformers, three phase lines of motor pass therethrough respectively, and power circuit is again through behind the current rectifying and wave filtering circuit; be connected with voltage stabilizing circuit, current rectifying and wave filtering circuit is made up of three Qiao Dui and an electric capacity.

2, motor protector as claimed in claim 1 is characterized in that ON-OFF control circuit is made up of midget relay and bidirectional triode thyristor.

3, as claim 1,2 described motor protectors, it is characterized in that also having one to regulate the running protection circuit, this circuit is made up of adjustable potentiometer and ammeter, is connected with ON-OFF control circuit with current rectifying and wave filtering circuit.