CN200983498Y - A phase-miss over-current protection start switch - Google Patents

Abstract

The utility model discloses an no-phase current-overloaded protecting starting switch, and is characterized in that the utility model comprises an alternating current contactor, an intermediate relay, a thermal protector, a start button, a stop button and a working indicating circuit, wherein three phases A, B, C of a three-phase supply are respectively connected with three input terminals of A, B, C of an alternating current contactor (J1), an (A1) terminal of an actuating coil of (J1) is connected with the B-phase of a main input terminal, an (A 2) terminal of the actuating coil of (J1) is connected with the C-phase of the main input terminal through a normally closed contact of a thermal protector (FR), a normally closed contact of a stop button (SB2), and a normally opened contact of the start button (SB1), one terminal of the actuating coil of an intermediate relay (J2) is connected with the A-phase output terminal of (J1), another terminal of actuating coil of the intermediate relay (J2) is connected with the B-phase output terminal, the C-phase output terminal of (J1) is connected with the joint point of the start button (SB1) and the stop button (SB2) through the normally closed contact of (J2). The utility model has the advantages that the circuit is simple, the actuation is quick, and the protection is excellent.

Description

A kind of over-current protection for the phase lacks starting switch

Technical field

Utility model relates to motor, especially the starting switch of motor.

Background technology

In industrial and agricultural production and all trades and professions, threephase motor is the major impetus of raising speed and benefit.The damage of threephase motor will bring no small economic loss and trouble to the user, and the easiest key factor that causes motor to damage is exactly a phase shortage.

The technology relevant with the application is overcurrent dropout type protection starting switch and phase shortage overcurrent motor protector; it all is to have adopted the overcurrent protection principle that these two kinds of protectors (starting switch) have a common ground; different is that the former is the deformation principle shake-up closing of contact by thermal element; the adhesive of vary off-line coil electricity, it is former and stop power supply that contactor thread off is disconnected main electricity.This protector is owing to adopted thermal element; thermal element heating at once causes sensitivity low under overcurrent condition, if also have the inoperative too greatly of drop-away current accent; too little can't the starting must be adjusted drop-away current according to power of electric motor and could realize.Also have a fatal shortcoming,, will cause the tripping coil can't adhesive, make the protection failure when any phase phase shortage that connects tripping coil.The latter be mutual inductance electric current when overcurrent occurring as control signal, this signal is amplified, the starting that makes executive component action control A.C. contactor with stop.The circuit complexity of this protector, inconvenient by dress.Because it is the principle that increases by motor open phase time electric current tool, the different phase shortage electric currents of motor power (output) have very big difference.Therefore it also must need to adjust protective current according to the size of motor, so just brings some inconvenience to the user, if also have protector itself to break down, will cause the protection failure.

Summary of the invention

The utility model provides a kind of new over-current protection for the phase lacks starting switch for solving the defective of above protector.

The utility model is by A.C. contactor J ₁, auxiliary relay J ₂, thermal protector FR, starting button SB ₁, stop button SB ₂And working indicating composition (seeing accompanying drawing 1), its circuit connecting relation is:

The A of three phase mains, B, C three-phase meet A.C. contactor J respectively ₁Three inputs of A, B, C, J ₁The A of actuation coil ₁The B phase of termination power input, J ₁The A of actuation coil ₂End successively through the normally-closed contact of overheat protector FR, stop knob SB ₂Normally-closed contact and start button SB ₁Normally opened contact insert the C phase of power input;

Auxiliary relay J ₂One termination J of actuation coil ₁The A phase of output, another termination J ₁The B phase of output; J ₁The C of output is through J ₂Normally opened contact meet start button SB ₁With stop button SB ₂Tie point.

The utility model has the advantages that: circuit is simple, is swift in motion, and damage causes any phase phase shortage no matter main power source still is ac contactor contact, and the protection starting switch is the action deenergization rapidly, has nothing to do with motor power (output) and electric current.The protector starting switch adopts the integrated water-proof design, produces different size, can be used as the general protection starting switch that a lot of open-air occasions are used.

Description of drawings

Fig. 1 is the circuit theory diagrams of the utility model embodiment.

Embodiment

Comprise shell when the application implements, A.C. contactor J shown in Figure 1 is installed in the shell ₁With auxiliary relay J ₂, start button SB is installed on the housing face-plate ₁, stop button SB ₂And indicator light LED ₁And LED ₂In addition, in circuit,, in A, B, C three-phase, be serially connected with thermal protector FR for overload protection.Resistance R ₁With indicator light LED ₁Constituted power indicating circuit, resistance R ₂With indicator light LED ₂Constituted working indicating.Its annexation is as described in the previous technique scheme.

Be clearer understanding the utility model, refer again to Fig. 1 its operation principle is described.When pressing start button SB ₁The time, A.C. contactor J ₁Adhesive, J _1-1, J _1-2, J _1-3The contact is closed simultaneously, auxiliary relay J ₂The energising adhesive, J ₂The normally opened contact closure, alternating voltage that C goes up mutually is through J _1-3, J ₂Normally opened contact, stop button SB ₂, thermal protector FR makes J ₁Realize self-locking; Unclamp starting button SB ₁, make this protection starting switch continue to keep starting state, no matter this moment is A.C. contactor J ₁Input still be the arbitrary phase phase shortage of output, all can cause J ₁, J ₂Dead electricity and discharging quits work this protection starting switch, reaches open-phase protection and irrelevant with size of current.When needs stop, click and stop knob SB ₂Can stop.Under non-non-full-phase state, as motor damage, overload, fault occur, thermal protector FR realizes action, and the normally-closed contact of FR disconnects, and makes J ₁Coil losing electricity, J ₁Discharge, this protection starting switch quits work, thereby has reached the duplicate protection of phase shortage, overload.

Claims (1)

1, a kind of over-current protection for the phase lacks starting switch is characterized in that, it is by A.C. contactor (J ₁), auxiliary relay (J ₂), thermal protector (FR), starting button (SB ₁), stop button (SB ₂) and the working indicating composition, its circuit connecting relation is:

The A of three phase mains, B, C three-phase meet A.C. contactor (J respectively ₁) three inputs of A, B, C, (J ₁) (the A of actuation coil ₁) the B phase of termination power input, (J ₁) (the A of actuation coil ₂) end successively through the normally-closed contact of overheat protector (FR), stop knob (SB ₂) normally-closed contact and start button (SB ₁) normally opened contact insert the C phase of power input;

Auxiliary relay (J ₂) a termination (J of actuation coil ₁) the A phase of output, another termination (J ₁) the B phase of output; (J ₁) C of output is mutually through (J ₂) normally opened contact meet start button (SB ₁) and stop button (SB ₂) tie point.

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