CN2409695Y

CN2409695Y - Intelligent protector for electric machine

Info

Publication number: CN2409695Y
Application number: CN 98246154
Authority: CN
Inventors: 黄国胜
Original assignee: Shanghai Ford Relay Co Ltd; Yueqing Ford Relay Research Institute; Yueqing Ford Thermal Relay Factory
Current assignee: Shanghai Ford Relay Co Ltd; Yueqing Ford Relay Research Institute; Yueqing Ford Thermal Relay Factory
Priority date: 1998-11-05
Filing date: 1998-11-05
Publication date: 2000-12-06
Anticipated expiration: 2008-11-05

Abstract

The utility model relates to an intelligent protector for an electric machine, which is composed of a sampling and working voltage circuit, a reference and signal voltage comparing circuit, a phase-failure working circuit, a delay circuit and an electromagnetic operating circuit. The induction current of a three-phase power supply line of an electric machine is taken out through a current transformer to be used for each circuit of the intelligent protector for electric machine. When the electric machine generates an over-current, a short-circuit or a rotation-blocking phenomanon under setting current, the electric machine is compared and delayed by 5-80 seconds through a change-over circuit; when the electric machine generates phase failure, a relay can be started, the normally-closed contacts of the electric machine are disconnected, a power supply is cut off, and meanwhile, the utility model is provided with the delay circuit so that the utility model can automatically eliminate misoperation caused by the interference of current when the electric machine is started.

Description

The intelligent motor protection device

The utility model relates to a kind of intelligent motor protection device.Belong to the automatic resist technology of motor field.

At present, the phenomenon of burning motor owing to the power supply phase shortage is very serious, and bimetal leaf that uses or thermal relay can not be implemented protection reliably to the motor power phase failure or over-current and-load now, and bimetal thermal relay is a kind of energy-consuming product.

The purpose of this utility model is exactly a kind of intelligent motor protection device that need not power consumption that can effectively implement the phase failure and overcurrent protection fast that designs in order to address the above problem.This device is identical with the bimetal thermal relay of same model in installation dimension, the mode of connection, electric current adjustment.

The utility model product mainly adopts the mode of connection of JR and contour structures (or the major loop wiring is a punching) circuit mainly to be made up of sampling, operating voltage loop, benchmark, signal voltage comparison loop, open phase protection loop, timing circuit and electromagnetism action circuit, can in time cut off the electricity supply reliably to overload, short circuit, the open phase fault of three phase electric machine.

Each function of the utility model product is achieved in that

Three phase mains by three corresponding motors of current transformers difference, take out three-phase electricity flow point two-way, the one tunnel after rectifying tube and electric capacity carry out rectification and filtering, a direct current voltage supply circuit be made work voltage, simultaneously under the situation of over current of motor, stall, the corresponding increase of the direct voltage of gained.In reference voltage relatively, circuit according to overcurrent what, corresponding delay a period of time, make the actuating of relay.Another road direction open circuit protection loop provides voltage, and under normal circumstances, the electric current of responding on three instrument transformers after rectification, the filtering, provides base current to triode through separately triode electric capacity, makes three triode saturation conductions.When occurring opening circuit mutually as any one, corresponding triode ends, and operating voltage provides operating current to action circuit, makes the actuating of relay, and its normally-closed contact separates, and cuts off the electricity supply at once.

Accompanying drawing 1: be intelligent motor protection device block diagram;

Accompanying drawing 2: be intelligent motor protection device circuit figure.

This utility model intelligent motor protection device is by motor overload, stall, short circuit current, and open-phase protection circuit and electromagnetism action circuit three parts are formed.

Motor overload, stall, short circuit current such as accompanying drawing 2 are comprising current transformer L ₁, L ₂, L ₃, rectifying tube D ₄, D ₅, D ₆, filter capacitor C ₄, adjustable resistance W ₁, potentiometer W ₂, resistance R ₅With time-delay assembly resistance R ₆, capacitor C ₅Form, as motor operate as normal under setting current, L ₁, L ₂, L ₃The electric current that induces is through D ₄, D ₅, D ₆Rectification is by C ₄After the filtering, at W ₁, W ₂, R ₅Last generation voltage is regulated W ₂Make action circuit just in time face Jie position, relay is failure to actuate, and its normally closed interlock provides path for the electricity consumption loop.If overload, stall, short circuit appear in motor, the also corresponding increase of induced current that corresponding current transformer produces, after the rectification at C ₄On voltage also increase, be distributed in W like this ₂On voltage along with C ₄The rising of voltage and raising, this voltage is through R ₆To C ₅Charge, time-delay 5-80 time second, make C ₅Voltage also increases, to reach the actuating circuit action.

Open-phase protection circuit such as accompanying drawing 2 are comprising current transformer L ₁, L ₂, L ₃, rectifying tube D ₁, D ₂, D ₃, filter capacitor C ₁, C ₂, C ₃, current-limiting resistance R ₁, R ₂, R ₃, triode BG ₁, BG ₂, BG ₃With load resistance R ₄, isolating diode D ₇Form.Under the normal condition, L ₁, L ₂, L ₃All have induced current to produce, D respectively hangs oneself ₁, D ₂, D ₃Rectification is at C ₁, C ₂, C ₃The certain voltage of last generation is through resistance R ₁, R ₂, R ₃Give BG after the current limliting ₁BG ₂, BG ₃Base stage bias current is provided, three triodes are saturation conductions simultaneously, the pressure drop on triode has only 0.9 volt, deficiency so that the electromagnetism actuating circuit move.When if power supply or motor any the phase failure occurs mutually, there is not induced current in the corresponding current transformer, corresponding triode ends because of no base current, thus operating voltage is through resistance R ₄With diode D ₇To C ₅(during motor rotation in 3 seconds) charges to the actuating circuit action in 1 second.

Electromagnetism actuating circuit such as accompanying drawing 2 are comprising triode BG ₄, BG ₅, diode D ₉Form with relay J, motor under the normal operation situation, C ₅On voltage be slightly smaller than BG ₄, BG ₅Cut-off region and the amplification region face the section that is situated between, like this, relay J because of having only atomic little undercurrent so that it moves adhesive, thereby guaranteed the normal operation of electrical appliance.But when overcurrent, stall, short circuit and the phase failure occurring, can both make C through above-mentioned analysis ₅On voltage raise, work as C ₅On voltage be elevated to BG ₄, BG ₅When the electric current after the amplification can make the relay J adhesive, its normally-closed contact disconnected, and cut off the loop of power consumption equipment, thereby had guaranteed the safety of power consumption equipment.

The characteristics of this Intelligent motor protecting device are that element is few, function is many, idle, The acting characteristic that simulates bimetal thermal relay is arranged, and its performance more is better than bimetallic The chip electrothermal relay, particularly sensitiveer to disconnected phase time, move extremely reliable, and electric Designed delay circuit in the road, the current interference during to electric motor starting and the electric current that is in operation Fluctuation disturb, the effect of automatic elimination is arranged, thereby the normal operation of motor is provided Reliable guarantee. In addition, the mounting structure of this device, appearance and size, electric current adjustment with The bimetal thermal relay of same model is identical, directly changes, and is extremely convenient.

Claims

1, a kind of intelligent motor protection device is characterized in that this device is made up of sampling, operating voltage loop, benchmark, signal voltage comparison loop, phase failure work loop, timing circuit and electromagnetism action circuit.

2, device according to claim 1 is characterized in that sampling, work loop by current transformer L1, L2, L3, rectifying tube D4, D5, D6, and filter capacitor C4 forms; The public ground of the termination of L1, L2, L3, the other end separately connect respectively and are connected to behind D4, D5, the D6 a bit in parallelly with C4, and as the positive pole in sampling and operating voltage loop, its negative pole is publicly.

3, device according to claim 1 is characterized in that benchmark, signal voltage comparison loop be made up of adjustable resistance W1, potentiometer W2, resistance R 5, three connect back and C4 parallel connection.

4, device according to claim 1, it is characterized in that the open phase protection loop by current transformer L1, L2, L3, rectifying tube D1, D2, D3, filter capacitor C1, C2, C3, resistance R 1, R2, R3, R4, triode BG1, BG2, BG3 and isolating diode D7 form; The public ground of the termination of L1, L2, L3, the other end separately divides two the tunnel respectively after meeting D1, D2, D3 respectively, one the tunnel respectively through C1, C2, C3 ground connection, each connects the b utmost point of BG1, BG2, BG3 another road through R1, R2, R3, the operating voltage positive pole connects the C utmost point of BG1 through R4, and the e utmost point of BG1 connects the C utmost point of BG2, and the e utmost point of BG2 connects the C level of BG3, the e utmost point ground connection of BG3 meets D7 to isolate at the C of the BG1 utmost point.

5, device according to claim 1 is characterized in that timing circuit by resistance R 6, and capacitor C5 forms, and the moving plate end of the termination W2 of R6, the other end connect the positive pole of C5, the negative pole of D7 and the positive pole of D8, the minus earth of C5 respectively.

6, device according to claim 1 is characterized in that the electromagnetism action circuit by diode D8, D9, and triode BG4, BG5 and relay J are formed; The negative pole of D8 connects the b level of BG4, and the e utmost point of BG4 connects the b utmost point of BG5, the e utmost point ground connection of BG5, and the end after J and the D9 parallel connection is connected to a bit in the C of BG4, the BG5 utmost point, the positive pole of another termination operating voltage.