CN2749157Y

CN2749157Y - Open-phase over-current protector for motor

Info

Publication number: CN2749157Y
Application number: CN 200420107408
Authority: CN
Inventors: 倪尧基; 吴亚芬
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-10-19
Filing date: 2004-10-19
Publication date: 2005-12-28
Anticipated expiration: 2014-10-19

Abstract

The utility model relates to an open-phase over-current protector for a motor, which comprises a housing body and a controlling circuit in the housing body, wherein, the controlling circuit comprises a current mutual inductor, an over-current signal detecting circuit, an A phase open-phase signal detecting circuit, a B phase open-phase signal detecting circuit, a C phase open-phase signal detecting circuit, an over-current setting circuit, a time delay circuit, an over-current voltage comparison circuit, an A, B and C three-phase open-phase comparison circuit, a locking circuit, a composite circuit, an output executive circuit and a power supply circuit. The three current mutual inductors are respectively penetrated on the three-phase electric lines of a motor, two groups of coils are wound on each mutual inductor, and the input end and the output end of the two groups of coils are connected. Iron cores in the mutual inductors are formed by coiling silicon sheets signals acquired by the mutual inductors are input the over-current setting circuit, and the time delay circuit by the signal detecting circuit and are input the composite circuit by the voltage comparison circuit. A high level signal is output to the executive circuit; therefore, the coil of a relay is switched off to protect the motor. Compared with the prior art, the open-phase over-current protector for the motor of the utility model has the advantages of simple structure, low cost, high sensibility and stable performance.

Description

Motor phase failure overcurrent protector

Technical field

The utility model relates to a kind of motor protector, especially a kind of threephase motor phase failure overcurrent protector.

Background technology

Motor usually can run into phenomenon such as the phase failure, overcurrent and causes burning in running, even human casualty accident takes place.In order to overcome this problem, people have taked the way protected with various relays.Having occurred some in recent years again protects with the circuit that discrete component adds the integrated circuit composition.The patent No. be " 95211151.9 ", " motor protector " it be provided with latching circuit, can be serially connected on the outer optional position of the self-keeping circuit of motor secondary control loop or self-keeping circuit, have wide adaptability, characteristics that cost is low.It is controlled A.C. contactor with controllable silicon as executive component and turn-offs, thereby makes motor break away from electrical network and shut down and obtain protection.Because controllable silicon compressive resistance consistency is not enough, insufficient sensitivity good, therefore, when running into one in the three-phase electricity and disconnecting mutually, controllable silicon is still conducting sometimes, and motor still phase failure running causes burning out; Moreover because it adopts the core material induction to produce electric current, because of the quality problems of magnetic material, magnetic flux is often saturated easily, so signal strength signal intensity is not enough, so still do not play protective effect when over current of motor.

Goal of the invention

The utility model is at the defective and the deficiency of above-mentioned prior art, for motor provide a kind of simple in structure, cost is low, the phase failure of stable performance, overcurrent protector.

Technical solution adopted in the utility model is for achieving the above object: this motor phase failure overcurrent protector comprises housing and inner control circuit thereof; this control circuit comprises current transformer; the over-current signal detecting circuit; the A phase; the B phase; C phase phase failure signal detection circuit; the overcurrent initialization circuit; delay circuit; the overcurrent voltage comparator circuit; the A phase; the B phase; C phase phase failure voltage comparator circuit; lock-in circuit; combiner circuit; output executing circuit and power circuit; described current transformer has three; on the equidirectional respectively three-phase wire that is through motor; be wound with two groups of coils on every instrument transformer; and headtotail; transformer iron core of the present utility model is to be rolled into by silicon steel sheet; and with the executive component of relay as output executing circuit; the signal that obtains on the current transformer is behind signal detection circuit; input overcurrent initialization circuit; delay circuit; again through voltage comparator circuit to combiner circuit; export the triode BG base stage of a high level signal in the output executing circuit; the break-make of control triode; thereby make relay coil energising or outage; its normally closed interlock is opened; close, reach the purpose of motor protection.

The utility model is because of moving in the not frequent phase failure, overcurrent operating state, therefore use relay, characteristics with the low good reliability of cost, adopt silicon steel sheet as transformer iron core and integrated circuit component simultaneously, compared with prior art, simple in structure, power consumption is little, the characteristics of highly sensitive, stable performance.

Description of drawings

Fig. 1 is the block diagram of the utility model circuit control section.

Fig. 2 is the utility model electrical schematic diagram.

Embodiment

This motor phase failure overcurrent protector comprises housing and inner control circuit thereof.This control circuit comprises current transformer, over-current signal detecting circuit, A phase, B phase, C phase phase failure signal detection circuit, overcurrent initialization circuit, delay circuit, overcurrent voltage comparator circuit, lock-in circuit, A phase, B phase, C phase phase failure voltage comparator circuit, combiner circuit, output executing circuit and power circuit.Wherein current transformer is three, and is through on A, B, the C motor three-phase wire.Transformer iron core is rolled into by silicon steel sheet, and is wound with L respectively on every iron core _A, L _A', L _B, L _B', L _C, L _C' two coils, ground connection behind two coil headtotails.One group of coil L wherein _A, L _B, L _CAn end meet rectifier diode D respectively ₁, D ₃, D ₅Positive pole, rectifier diode D ₁, D ₃, D ₅Negative pole be connected together and and capacitor C ₁Positive pole, resistance R ₁An end join C ₁Negative pole and resistance R ₁Other end ground connection.By L _A, L _B, L _C, D ₁, D ₃, D ₅, C ₁, R ₁Form the over-current signal detecting circuit.The overcurrent initialization circuit is by resistance R ₈, potentiometer W and resistance R ₉Be serially connected, wherein resistance R ₈The other end and rectifier diode D ₁, D ₃, D ₅Negative pole join resistance R ₉Other end ground connection, the sliding point of potentiometer W is connected to resistance R ₁₀, R ₁₀The other end and capacitor C ₅Positive pole join, be attempted by integrated voltage comparator IC ₁Positive pole, capacitor C ₅Minus earth, resistance R wherein ₁₀, capacitor C ₅Formed delay circuit.The overcurrent voltage comparator circuit is by resistance R ₁₁, voltage-stabiliser tube Z ₄, diode D ₇, voltage comparator ic ₁Form.Resistance R wherein ₁₁One terminate at power positive end, the other end and voltage-stabiliser tube Z ₄Negative pole joins, and the voltage-stabiliser tube positive pole meets diode D ₇Positive pole, diode cathode ground connection, wherein resistance R ₁₁With voltage-stabiliser tube Z ₄The contact of negative pole and integrated comparator IC ₁Negative pole join voltage as a comparison, integrated voltage comparator IC ₁Output with by diode D ₈, D ₉, D ₁₀, D ₁₁Diode D in combiner circuit of forming or the title OR circuit ₈Positive pole joins, diode D ₈Negative pole and resistance R ₁₃The serial connection back joins with the base stage of triode BG.Output executing circuit is by relay J, triode BG, diode D ₁₃, resistance R ₁₄Form.Wherein triode BG emitter and resistance R ₁₄Join R ₁₄Other end ground connection.One end of the collector electrode of triode BG and relay J coil and diode D ₁₃Positive pole join D ₁₃Negative pole and another termination positive source of relay coil J.Lock-in circuit is by resistance R ₁₂With diode D ₁₂Form R ₁₂An end and diode D ₁₂Negative pole join D ₁₂Positive pole be connected on integrated comparator IC ₁Output, resistance R ₁₂The other end be connected on IC ₁Positive pole on.A phase phase failure signal detection circuit is by mutual inductor coil L _A', diode D ₂, capacitor C ₂, resistance R ₂, R ₅Form.Be through the another coil L of the instrument transformer on the A phase electric wire _A' the other end and rectifier diode D ₂Positive pole join diode D ₂Negative pole and capacitor C ₂Positive pole and resistance R ₂, R ₅An end join C ₂Negative pole, R ₂Other end ground connection, R ₅Another termination A phase phase failure voltage comparator ic ₂Negative pole.The IC of voltage comparator ₂Negative pole and voltage-stabiliser tube Z ₁Negative pole join voltage-stabiliser tube Z ₁Plus earth, the D utmost point is connected on voltage-stabiliser tube Z ₄Positive pole and diode D ₇On the positive contact, output stage is connected on the diode D in the combiner circuit ₉Positive pole on, diode D ₉Negative pole and resistance R ₁₃Be connected on behind the polyphone on the base stage of the triode BG in the output executing circuit.B phase phase failure signal detects, voltage ratio, synthetic, output executing circuit is by coil L _B', diode D ₄, capacitor C ₃, resistance R ₃, R ₆, voltage comparator ic ₃With diode D ₁₀Form.C phase phase failure signal detects, voltage ratio, synthetic, output executing circuit is by coil L _C', diode D ₆, capacitor C ₄, resistance R ₄, R ₇, voltage comparator ic ₄With diode D ₁₁Form.The phase failure observing and controlling process of B phase, C phase is identical with A phase phase failure observing and controlling process, respectively by the instrument transformer another coil L on B phase or the C phase electric wire _B', L _C' finally be connected with the base stage of triode BG in the output executing circuit.

Power circuit has adopted capacitance decompression, rectification, filtering, voltage stabilizing circuit commonly used, and it is by capacitor C ₆, C ₇, resistance R ₁₅, R ₁₆, R ₁₇, diode D ₁₄, D ₁₅, D ₁₆, D ₁₇, voltage-stabiliser tube Z ₅Form.

By the three-phase wire that power supply comes, pass three current transformers of protector respectively, by the normally open contact of A.C. contactor, receive on the motor then again.Behind the power turn-on, the coil of A.C. contactor is switched on by the normally closed interlock of relay, and the normally open contact closure is rotated motor.

Be wound with two groups of coils on every transformer iron core, be respectively L _A, L _A', L _B, L _B', L _C, L _C', when having alternating current to pass through on the three-phase wire, on coil, induce sampled signal voltage respectively, wherein one group of coil L _A, L _B, L _COn signal voltage, through rectifier diode D ₁, D ₃, D ₅Rectification, capacitor C ₁Filtering, load resistance R ₁, after synthesizing and by R ₈, W, R ₉The bleeder circuit of forming takes out detection signal voltage, behind delay circuit, is added in the overcurrent voltage comparator ic ₁Positive pole on, be added in integrated comparator IC by the voltage that takes out in the voltage stabilizing circuit ₁The negative pole voltage of making comparisons.When one on the three-phase wire mutually or a few phase current when excessive, the voltage after synthetic is added in the overcurrent voltage comparator ic by bleeder circuit ₁Voltage on the positive pole is greater than the voltage on the negative pole, and comparator output high level is through synthesizing the diode D in the circuit ₈Pass through resistance R again ₁₃Be added on the base stage of triode BG, the triode conducting makes the coil conducting of relay J, and normally closed interlock disconnects, and the normally open contact of A.C. contactor is resetted, thereby the three-phase voltage that is added on the motor is opened circuit, and has protected motor with this.

Another group coil L on the instrument transformer _A', L _B', L _C' on signal voltage through diode D ₂, D ₄, D ₆Rectification, capacitor C ₂, C ₃, C ₄Filtering is taken out direct-flow signal voltage through resistance R ₅, R ₆, R ₇Be added in phase failure voltage comparator ic ₂, IC ₃, IC ₄Negative pole on, be connected to identical voltage-stabiliser tube Z respectively between negative pole and the ground wire ₁, Z ₂, Z ₃In order to the protection comparator, be added in the voltage of making comparisons on the positive pole of three phase failure voltage comparators by the voltage that takes out in the voltage stabilizing circuit.When one in the three-phase wire mutually or several when opening circuit mutually, no current flows through electric wire, instrument transformer L _A', L _B', L _C' coil is provided with and induces signal voltage, phase failure voltage comparator ic ₁, IC ₂, IC ₃The voltage of last negative pole just is lower than anodal comparative voltage, and high level signal of comparator output passes through resistance R behind synthetic circuit ₁₃Be added on the base stage of triode BG, make the triode conducting, the coil conducting of relay J, normally closed interlock disconnects, and the normally open contact of A.C. contactor is resetted, thereby the three-phase voltage that is added on the threephase motor is disconnected, and has protected motor with this.

Claims

1; a kind of motor phase failure overcurrent protector; it comprises housing and inner control circuit thereof; this control circuit comprises current transformer; the over-current signal detecting circuit; the A phase; the B phase; C phase phase failure signal detection circuit; the overcurrent initialization circuit; delay circuit; the overcurrent voltage comparator circuit; the A phase; the B phase; C phase phase failure voltage comparator circuit; lock-in circuit; combiner circuit; output executing circuit and power circuit; described current transformer has three; on the equidirectional respectively three-phase wire that is through motor; be wound with two groups of coils on every instrument transformer; and headtotail; it is characterized in that the iron core in the current transformer is to be rolled into by silicon steel sheet; the signal that obtains on the current transformer is behind signal detection circuit; input overcurrent initialization circuit; delay circuit; again through voltage comparator circuit to combiner circuit, export a high level signal to output executing circuit.

2, motor phase failure overcurrent protector according to claim 1 is characterized in that described output executing circuit is by triode BG, relay J, diode D ₁₃, resistance R ₁₃, R ₁₄Form, its repeat circuit is as executive component, and the base stage of triode BG is passed through R ₁₃Join the collector connecting relay J of triode BG with the combiner circuit output.

3, motor phase failure overcurrent protector according to claim 1 and 2 is characterized in that described over-current signal detecting circuit is by one group of coil L in three instrument transformers _A, L _B, L _CAnd rectifier diode D ₁, D ₃, D ₅With filter capacitor C ₁, load resistance R ₁Form; The overcurrent initialization circuit is by resistance R ₈, R ₉And adjustable potentiometer W forms; Delay circuit is by resistance R ₁₀, capacitor C ₅Form; The overcurrent voltage comparator circuit is by integrated voltage comparator IC ₁, resistance R ₁₁, voltage-stabiliser tube Z ₄, diode D ₇Form; Lock-in circuit is by resistance R ₁₂With diode D ₁₂Form; Combiner circuit is by diode D ₈, D ₉, D ₁₀, D ₁₁The OR circuit of forming; A phase phase failure detecting circuit is by mutual inductor coil L _A', rectifier diode D ₂, filter capacitor C ₂, load resistance R ₂Form; B phase phase failure detecting circuit is by mutual inductor coil LB ', rectifier diode D ₄, filter capacitor C ₃, load resistance R ₃Form; C phase phase failure detecting circuit is by mutual inductor coil L _C', rectifier diode D ₆, filter capacitor C ₄, load resistance R ₄Form; A phase, B phase, C phase phase failure voltage comparator circuit are by integrated voltage comparator IC ₂, IC ₃, IC ₄And resistance R ₁₁, voltage-stabiliser tube Z ₄And diode D ₇Form; Power circuit is by capacitor C ₆, C ₇, resistance R ₁₅, R ₁₆, R ₁₇, diode D ₁₄, D ₁₅, D ₁₆, D ₁₇, voltage-stabiliser tube Z ₅Form.