CN2150652Y - Protector for three-phase motor without power supply - Google Patents

Abstract

The utility model belongs to a protector for a three-phrase asynchronous motor, particularly a protector for three-phase motor without power supply. The utility model is composed of an and gate circuit, a setting circuit, a flip-flop control circuit and a display circuit which are composed of a current mutual inductor, triodes, controlled silicon, etc. The utility model utilizes AC mutual coils to induce voltage which is transferred to flip-flop control circuit via an RC rectifying circuit to achieve the automatic attraction and release of a magnetic starter, and when a short-circuit fault, a phase interruption fault, an earth connection fault, an over-current fault, an over-electric voltage fault, an under-voltage fault, a momentary fluctuation of the electric voltage fault, or an electrical leakage fault, etc. arise, the utility model can cut off the power supply to protect the running of the motor. The utility model is suitable for AC electric motors with power which is within 1-150KW and current which is within 1-300A.

Description

Protector for three-phase motor without power supply

The utility model belongs to the protective device of threephase asynchronous machine, particularly a kind of non-transformer threephase motor protector.

At present, overload often appears in the interchange threephase asynchronous machine that uses, overcurrent or phase failure phenomenon, influence is produced, and uses three-phase motor protector that the overload of three phase electric machine, phase shortage, under voltage etc. are played a protective role, generally be to utilize the relay of the external power supply of original motor to finish the break-make of magnetic force actuating coil, this protector is made up of transformer, relay, three-phase instrument transformer etc., complex structure, and volume is big, the contact is many, the failure rate height; Another kind is hot relay protector, utilizes bimetallic expander control contact protection motor, but because of the bimetal leaf non-refractory or cross coldly and malfunctioning, problems such as malfunction or break time be long takes place, and makes troubles to the user.

The purpose of this utility model is to overcome above technical deficiency, and provides a kind of simple in structure, and is highly sensitive, the threephase motor protector of good reliability.

The utility model is achieved in that a kind of non-transformer threephase motor protector, by current transformer, triode, controllable silicon etc. form AND circuit, the circuit of adjusting, bistable state control and display circuit.The inferior utmost point of current transformer connects rectification circuit, rectification circuit also connects capacitor C 4 filtering and links to each other with AND circuit, resistance R 1, R4, R7 connect the collector electrode (the C utmost point) of BG1, BG2, BG3, resistance R 2, R5, R8 connect the base stage (the b utmost point) of BG1, BG2, BG3, triode conducting, the C utmost point and e utmost point ground connection.

The contactless circuits for triggering of bistable state are linked to each other with the G level of SCR2 through resistance R 13 by the anode A of SCR1, and the anode A of SCR1 links to each other with the anode A of SCR2 through R11, R12, and the anode A of SCR2 constitutes the loop through diode D12 to exchanging the contactor sucking coil.

Non-transformer threephase motor protector has faults such as short circuit, the phase failure, ground connection, overcurrent, overvoltage, under voltage, voltage momentary fluctuation, electric leakage and cuts off the electricity supply the transient protection motor at once.

Specify with by way of example below in conjunction with accompanying drawing.

Fig. 1 shows non-transformer threephase motor protector electrical schematic diagram.

Fig. 2 shows non-transformer threephase motor protector user block diagram.

Among the figure; non-transformer threephase motor protector is by current transformer; triode; controllable silicon is formed AND circuit; the circuit of adjusting; bistable state control and display circuit; current transformer LHA; LHB; the first utmost point of LHC meets main contact A; B; C; the inferior utmost point meets D1; D2; D3; D4; D5; the rectification of D6 rectifier diode input; and connect capacitor C 4 filtering and link to each other with AND circuit; resistance R 1; R4; R7 connects BG1; BG2; the transistor collector of BG3 (the C utmost point); resistance R 2; R5; R8 connects the BG1 of triode; BG2; the base stage of BG3 (the b utmost point); triode conducting, the C utmost point and the e utmost point (emitter) ground connection.

The contactless circuits for triggering of bistable state are by unidirectional bridge rectifier diode D12 forward conduction, trigger controllable silicon anode A and negative electrode K conducting to earth point M through resistance R 11, R12, R13 to controllable silicon SCR 2 control utmost point G, constitute the loop through unidirectional bridge rectifier diode D15 to exchanging the contactor sucking coil again, motor runs well.

During use; the motor three-phase power line is penetrated respectively in the instrument transformer hole; connect the motor wiring terminal; machine outer terminal serial connection magnetic starter magnet exciting coil; restart the motor button; electric motor starting; with setting current with band switch or adjustable resistance capacity according to motor; rated current is adjusted the motor protecter potentiometer; when the main electrical scheme end transships, short circuit or open phase fault, cut off the magnetic starter coil power immediately, motor outage stall; the luminous tube demonstration is broken down, and avoids the scaling loss motor.

In three phase mains, any phase or two-phase are opened a way, then this middle mutually current vanishes.The phase failure of example A phase, then A phase mutual inductor LHA no signal output, triode BG1 base stage b no signal becomes cut-off state by conducting; And two-phase (B, C) has signal in addition; mutual inductor LHB, LHC induce voltage; by the electric current of D3, D5 output, by resistance R 1, D8 rectification output high potential, the control utmost point G that delivers to SCR1 triggers; the anode A current potential of SCR2 reduces; become by conducting and to end, cut off the power supply of A.C. contactor sucking coil, magnetic starter discharges; motor shuts down, the safe operation of protection motor.

As the motor overload running, current of electric surpasses the setting current value, after R10 resistance reduces, enters SCR1 control utmost point G triggering signal after the D11 rectification; the SCR1 conducting, SCR2 ends, and cuts off A.C. contactor sucking coil power supply; magnetic starter discharges, and motor shuts down, the protection motor.

Non-transformer threephase motor protector at 1-150KW, the uniterrupted duty between the electric current 1-300A, is interrupted duty, protections such as the alternating current motor of short time duty and various power line overload, short circuit, the phase failure repeatedly applicable to the AC electrical acc power.

Claims (1)

1; a kind of non-transformer threephase motor protector; by current transformer; triode; controllable silicons etc. are formed AND circuit; the circuit of adjusting; bistable state control and display circuit; it is characterized in that current transformer LHA; LHB; the secondary access D1 of LHC coil; D2; D3; D4; D5; the rectification of D6 rectifier diode input; and connect capacitor C 4 filtering and link to each other with AND circuit; resistance R 1; R4; R7 connects BG1; BG2; the collector electrode of BG3 (the C utmost point); resistance R 2; R5; R8 connects BG1; BG2; the base stage of BG3 (the b utmost point); the bistable state control circuit is linked to each other with the G level of SCR2 through resistance R 13 by the anode A of SCR1; the anode A of SCR1 is through R11; R12 links to each other with the anode A of SCR2, and the anode A of SCR2 constitutes the loop through diode D12 to exchanging the contactor sucking coil.

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