CN2141140Y

CN2141140Y - Phase-fault and overload protection for three-phase motor

Info

Publication number: CN2141140Y
Application number: CN 92241196
Authority: CN
Inventors: 谢祖均
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-11-07
Filing date: 1992-11-07
Publication date: 1993-08-25
Anticipated expiration: 2002-11-07

Abstract

The utility model provides a loss of phase and overload protection for three-phase motor, comprising a housing circuit board, a relay and a display circuit. The utility model is characterized in that one end of inductance coils L4<4> is connected with an external binding post 5, and the other end of the inductance coils L4<4> is connected with the normally closed contact of the relay. The loss of phase and overload protection for three-phase motor adopts a transistor to control an electromagnetic relay to cut off the power supply when a motor runs under the situation of loss of phase or overload to achieve the purpose of protecting quickly and reliably the motor. The utility model has the advantages of simple wire connection, small volume, integral encapsulation, non-requirement of a power supply for protector and strong anti-interference of environment ability.

Description

Phase-fault and overload protection for three-phase motor

The utility model relates to a kind of threephase motor protector, belongs to the emergency protective device field.

Aborning, burning more than 90% of threephase motor is to cause because of motor phase shortage or overlond running.At present; existing kinds of protect device is protected motor, but the employing thermal relay that these protections have is protected not prompt enough, reliable; what have uses integrated package; the wiring complexity is subject to Effect of Environmental and misoperation, and the protection range that also has is less; can not protect motor phase shortage, overlond running simultaneously; and protector need be established the power transformer power supply in addition mostly, has increased installation difficulty and cost.

The purpose of this utility model is to provide a kind of employing electromagnetic relay, does not need to establish the protector power supply in addition, and wiring is simple, is convenient to install, and anti-environmental interference ability is strong, can protect the protector of motor when phase shortage or overlond running in time, reliably.

The utility model is realized its purpose as follows: be provided with an inductance coil L in the protector power circuit ₄, the one end is connected with outer terminal 5, and the other end is connected relay J coils L with the normally closed point 2 of relay J ₄Reach outer terminal 5 and connect with the control coil of A.C. contactor CJ, the normally closed point 1 of it another is connected with outer terminal 4, controls its contact action, the diode 2CZ in the signal power source circuit by open-phase protection circuit, overload protecting circuit ₄, 2CZ ₅, 2CZ ₆Respectively with rectifying tube 2CZ ₁, 2CZ ₂, 2CZ ₃Reversal connection.

The transistor BG of the utility model open-phase protection circuit ₁Base stage and the reversal connection diode 2CZ in the signal power source circuit ₄, 2CZ ₅, 2CZ ₆Anode connect, simultaneously with overload protecting circuit in transistor BG ₆Collector electrode connect transistor BG ₃Collector electrode be connected BG with the solenoid of relay J ₁, BG ₃, BG ₆Emitter all be connected with the protector power cathode.Resistance R in the overload protecting circuit ₇With the reversal connection diode 2CZ in the signal power source circuit ₄Or 2CZ ₅Or 2CZ ₆Negative electrode connect.

Advantage of the present utility model is that wiring is simple, and volume is little, adopts integrated encapsulation; be convenient to install, do not need to establish in addition the protector power supply, the protection in the time of reliably realizing faults such as motor generation phase shortage, overloads; antijamming capability is strong, and protective rate can reach more than 98%, and remarkable economic efficiency is arranged.

Embodiment further specifies the utility model below in conjunction with accompanying drawing.

Fig. 1 is a line map of the present utility model.

Fig. 2 is a use scheme of installation of the present utility model.

Fig. 3 is a surface structure schematic diagram of the present utility model.

The supply voltage of the utility model protector passes through inductance coil L from the control coil of A.C. contactor CJ ₄Utilize the self coupling form to produce, after rectification, filtering, voltage stabilizing, use for protector.Three power lines of motor pass three through

wires holes

6,7,8 of protector respectively, and are big inadequately as through wires hole, also can adopt the form wiring of shunting.During the motor operation, the inductor L in the signal power source circuit ₁, L ₂, L ₃Just produce induced voltage, after rectification, filtering, become signal voltage.

When motor D normally moved, the protector supply voltage was through resistance R ₄Make transistor BG ₁Conducting, transistor BG ₂Base potential be electronegative potential, transistor BG ₂, BG ₃All be in cut-off state.When phase-deficient operation, the inductor of institute's phase shortage does not just have voltage to produce, and flows through transistor BG ₁The electric current of base stage just can be by the reversal connection diode and the resistance inflow place of institute's phase shortage one tunnel, BG ₁Base potential becomes electronegative potential, BG ₁End, power supply passes through resistance R ₆, R ₅To capacitor G ₄Charging is charged to certain hour, transistor BG ₂Base potential become high potential, BG ₂Conducting, BG ₃Also conducting is because of transistor BG ₃Be connected in series BG with the solenoid of relay J ₃After the conducting, relay J promptly gets electronic work, and its normally closed point 1 separates with 2, cuts off main power source, and D protects to motor.

When motor D did not have overlond running, the protector supply voltage arrived transistor BG after voltage stabilizing ₅Base stage, BG ₅Conducting, transistor BG ₆Base stage is an electronegative potential, BG ₆End.Pass through to adjust potentiometer W during the dress protector ₁Make transistor BG ₄Just in time end.When motor D overlond running, overload signal raises the induced voltage of inductor, through resistance R ₇, deflection machine W ₁And resistance R ₈Make transistor BG ₄Base potential is a high potential, BG ₄Conducting makes BG ₅End, electric current is to capacitor C ₇Charging is charged to transistor BG behind the certain hour ₆Base potential is a high potential, BG ₆Conducting, thus make BG ₁Ended by the conducting change, process after this is the same with aforementioned open-phase protection, and main power source is cut off in the relay J action.

Obtaining with overload protecting circuit of the display circuit signal of protector is synchronous, in the time of overload protection, and transistor BG ₇Conducting, luminous tube D ₁Get electroluminescence, promptly show overload.Use in the scheme of installation at Fig. 2, QA is a start button, and TA is a stop button, because protector has adopted the RC delay circuit, so can not influence the startup of motor.Knob 3 is adjusted in the load of adjusting on the protector, can protect to the motor of 200KW 100KW, and very big adaptability is arranged.

Claims

1, a kind of threephase motor phase shortage overload protective device comprises housing, circuit board, relay J and display circuit, it is characterized in that being provided with in the protector power circuit inductance coil L ₄, the one end is connected with outer terminal 5, and the other end is connected relay J coils L with the normally closed point 2 of relay J ₄Reach outer terminal 5 and connect with the control coil of A.C. contactor CJ, the normally closed point 1 of it another is connected with outer terminal 4, controls its contact action, the diode 2CZ in the signal power source circuit by open-phase protection circuit, overload protecting circuit ₄, 2CZ ₅, 2CZ ₆Respectively with rectifying tube 2CZ ₁, 2CZ ₂, 2CZ ₃Reversal connection.

2, protector according to claim 1 is characterized in that the transistor BG of open-phase protection circuit ₁Base stage and the reversal connection diode 2CZ in the signal power source circuit ₄, 2CZ ₅, 2CZ ₆Anode connect, simultaneously with overload protecting circuit in transistor BG ₆Collector electrode connect transistor BG ₃Collector electrode be connected BG with the solenoid of relay J ₁, BG ₃, BG ₆Emitter all be connected with the protector power cathode.

3, according to claim 1 and 2 described protectors, it is characterized in that the resistance R in the overload protecting circuit ₇With the reversal connection diode 2CZ in the signal power source circuit ₄Or 2CZ ₅Or 2CZ ₆Negative electrode connect.