CN2152336Y

CN2152336Y - Motor protector

Info

Publication number: CN2152336Y
Application number: CN 93210302
Authority: CN
Inventors: 姚宝华
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-04-22
Filing date: 1993-04-22
Publication date: 1994-01-05
Anticipated expiration: 2003-04-22

Abstract

The utility model discloses a motor protector, comprising an insulating outer shell, the protection circuit of a transformer installed in the outer shell, a terminal installed on the surface of the outer shell, a control button, and a threading hole, wherein, the protection circuit of the transformer comprises a current mutual inductor circuit, a resistance-capacity decompression and rectification circuit, and a transistor amplifying circuit. When in use, motor power supply lines are arranged in the threading hole and generate induced electromotive force on the both ends of the transformer; the induced electromotive force passes through the resistance-capacity decompression and rectification circuit, and the transistor amplifying circuit controls a relay to work. Thus, the motor protector effectively protects a motor. The utility model has the advantages of low cost, integrative integral structure, convenient installation and wire connection, and high reliability.

Description

Motor protector

The utility model relates to a kind of motor protecter, belongs to circuit protection device.

For preventing motor in use,, need install motor protecter additional because of various factors breaks down and even burns.Can be divided into voltage-type and current mode protector two big classes by its principle.

After the voltage-type protector utilized the three phase mains phase failure, its neutral point voltage no longer was zero characteristics, and this signal is changed input amplifier and connects trip gear, cut off the electricity supply.But can't protect motor overload, overheated etc., and the imbalance of three characteristics of the middle term power supply itself and load, often cause neutral point excursion, thereby cause malfunction.

The current mode protector utilizes instrument transformer, makes the power supply power line by current transformer, then produces induced electromotive force at instrument transformer two ends.When motor broke down, the variation of instrument transformer two end induced electromotive forces was by the action of transistor circuit control relay, to cut off the electricity supply.This type of protector is not influenced by neutral point, and good reliability is applied widely.But also exist, owing to adopt transformer step-down, cost height, volume big; Still need and dispose corresponding connection control unit, by the dress trouble, inconvenience is keeped in repair.

Provide for this reason a kind of simple in structure, parts are integrated, and reduce cost, the motor protecter by dress, easy-to-connect is the purpose of this utility model.

Technical solutions of the utility model are as follows: it by insulation crust, be installed in the instrument transformer protective circuit in the housing, the terminals that are installed in surface of shell, control button and through wires hole and form, wherein the instrument transformer protective circuit is made up of current transformer circuit, resistance-capacitance depressurization, rectification circuit and transistor amplifier circuit.Insulation crust is harmonious by front and back two parts that are mutually symmetrical and is integral; through wires hole runs through before and after the shell; be provided with instrument transformer around the through wires hole, inboard two ends of shell are respectively placed the groove of protective circuit plate by one, and link to each other with terminals with the panel control button by lead respectively.Signal is imported through instrument transformer, after resistance-capacitance depressurization, the rectification, amplifies control relay by transistor, thereby realizes electric motor protecting.

Accompanying drawing 1 is the utility model structural representation.

Accompanying drawing 2 is the utility model and motor winding diagram.

Accompanying drawing 3 is the utility model circuit theory diagrams.

Now the utility model is described in further detail in conjunction with the accompanying drawings: as shown in the figure; protector monolithic case (1) adopts injection molded of thermoset plastics; its inboard two ends are respectively by the groove of placing the protective circuit plate is arranged; circuit board can be fixed after inserting; run through a circular through wires hole (2) before and after the shell (1); the instrument transformer of through wires hole (2) suit coiling all around, terminals (3) and control button (4) are established in shell (1) surface, and its overall structure is integrated.During use three-phase power line is through in the through wires hole (2), by the set terminals (3) in shell (1) surface motor power is linked to each other with the protective circuit power supply, operate control button (4) and get final product actuating motor this moment, protects simultaneously.

The utility model circuit design is as follows: it is made up of current transformer circuit, resistance-capacitance depressurization, rectification circuit, transistor amplifier circuit and relay.Wherein, current transformer LA, LB, LC constitute input circuit; Resistance R ₁, R ₂, capacitor C ₁Constitute the resistance-capacitance depressurization part, diode V ₁-V ₄Constitute the bridge rectifier part, resistance R ₃, capacitor C ₂, voltage-stabiliser tube V ₁₀Constitute the filtering voltage regulation part, more than the power circuit of the synthetic protective circuit of three parts, and adopt motor power, owing to adopt the step-down of resistance-capacitance depressurization instead of transformers, so cost reduction, volume-diminished, minimizing terminals quantity.Transistor amplifier circuit is by resistance R ₄-R ₆, capacitor C ₃-C ₅, diode V ₅-V ₇The signal filtering, rectifying part and the transistor V that constitute ₁₁-V ₁₃Amplifier section that constitutes and relay J are formed.

Under the normal condition, operation starting button QA, relay J gets electric, its contact J _1-1By often open transfer to normally closed, this moment connect A.C. contactor JC coil, make it adhesive, electric motor starting.Electric current in three power lines of motor this moment produces induced electromotive force at its two end, respectively through resistance R through current transformer LA, LB, LC ₄-R ₆, capacitor C ₃-C ₅, diode V ₅-V ₇The filtering that forms, rectification input transistors V ₁₁-V ₁₃Base stage and emitter between, make it by by becoming conducting, keep the relay J adhesive, motor runs well.During operation stop button TA, relay J discharges, and A.C. contactor JC discharges, and motor shuts down.

When breaking down, if a certain phase phase failure, the induced electromotive force that then corresponding current transformer two ends produce is zero, and corresponding transistor transfers to and ending, and relay J discharges, A.C. contactor JC outage, and cut off the electricity supply.

Use the utility model; structural entity is integrated; by dress, easy to maintenance; adopt the resistance-capacitance depressurization instead of transformers; reduce cost, volume is little and can stop high frequency waves and other signal disturbs, and can prevent malfunction; realize to the electric motor protecting under the forceful electric power safety, reliable by low-voltage control circuit.

Claims

1, a kind of motor protecter; it is characterized in that by insulation crust, be installed in the instrument transformer protective circuit in the housing, the terminals that are installed in surface of shell, control button and through wires hole and form; produce induced signal by instrument transformer, input protection circuit is realized the starting of motor or is stopped.

2, motor protecter as claimed in claim 1 is characterized in that insulation crust is harmonious by front and back two parts that are mutually symmetrical to form that described through wires hole runs through shell, is provided with instrument transformer around the through wires hole; Inboard two ends of shell are respectively pressed the groove of a placement protective circuit plate; And link to each other with terminals with the control button of panel by lead respectively.

3, motor protecter as claimed in claim 1; it is characterized in that the instrument transformer protective circuit is made up of current transformer circuit, resistance-capacitance depressurization, rectification circuit and transistor amplifier circuit; signal is imported through instrument transformer; after resistance-capacitance depressurization, the rectification; amplify control relay by transistor, realize electric motor protecting.