CN2388760Y

CN2388760Y - Under-voltage open-phase protector

Info

Publication number: CN2388760Y
Application number: CN 98218384
Authority: CN
Inventors: 王书镇
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-08-20
Filing date: 1998-08-20
Publication date: 2000-07-19
Anticipated expiration: 2008-08-20

Abstract

The utility model relates to an under-voltage phase interruption and phase-faulty protector, comprising a DC power supply, a network voltage checking circuit, a regulating circuit, voltage sampling testing circuits which are arranged before and behind an alternating current contactor, a two-channel controlled output circuit of an integrated voltage comparator, and a display circuit. The utility model adopts three integrated circuits. The protection function is full. In particular, the utility model can avoid the accidents of the burn-out of motors which are caused by undervoltage, and the phase interruption accidents which are caused by the arc erosion of the main contact of the alternating current contactor. The utility model also has the function of indicator light display function of three power supply operating conditions which are the normal operating condition, the under-voltage operating condition, and the phase-faulty and phase interruption operating condition.

Description

Under-voltage phase failure fault-phase protection device

That the utility model relates to that a kind of threephase motor uses is under-voltage, the phase failure, fault-phase protection device.

(patent No.: 95218330.7) disclose a kind of threephase motor protector that adopts the forward and backward side of A.C. contactor all to have the voltage sample testing circuit, its advantage is that the phase failure and the misphase accident that it can protect motor to avoid occurring because of A.C. contactor the place ahead circuit can protect motor to avoid the long-term use of A.C. contactor main contacts to disconnect the rear circuit phase failure accident that causes because of the thermal element (resistance wire) of arc erosion and thermal relay again to the inventor at utility model patent " misphase and phase failure general protection device ".Wherein the phase failure accident that causes because of the main contacts arc erosion will account for more than 40% of threephase motor circuit inter-burnout-ing accident usually.

According to investigations, in China rural area because 380 volts of line voltages often are lower than the low-voltage lower limit (342 volts) of regulation, sometimes even be reduced to 320 volts.The threephase motor that drives water pump moves under undervoltage condition, and the electronic board number that burns because of electric current is excessive is considerably beyond the platform number that burns because of the phase failure.

The purpose of this utility model is that design a kind ofly can keep the existing phase failure of former protector, fault-phase protection function, can increase not only under-voltage protection function and structure but also change little threephase motor protector.

The purpose of this utility model is achieved in that it is made up of base, housing and a printed circuit board with a plurality of binding posts.

Technical characterstic of the present utility model is to adopt integrated voltage comparator JC ₁And JC ₂, JC ₁Output is connected with relay K A1 through relay K A2 again, and circuit is simple and direct; Adopt two independently voltage sample testing circuits: the voltage sample testing circuit in A.C. contactor KM the place ahead has mistake, phase failure measuring ability, and the voltage sample testing circuit at A.C. contactor KM rear only has phase failure measuring ability; Adopt JC ₁Homophase, anti-phase two inputs are to inverter V ₅The voltage signal that provides compares and differentiates, with decision JC ₁Output current whether; Adopt JC ₁Gating end ST by changing the control level height, with decision JC ₁The function that whether has output current after the comparison.Integrated voltage comparator JC ₂Homophase, anti-phase two casees go into end to compare and differentiate with decision JC with the voltage signal of line voltage size variation and the burning voltage signal of setting ₂Whether output current is to drive relay K A ₂

Below in conjunction with accompanying drawing the utility model is elaborated:

Fig. 1, Fig. 2 are respectively the utility model electric hookup and schematic diagram.

As seen from Figure 1, the three-phase circuit L in 1 of the utility model base, 2,3 binding posts and A.C. contactor KM the place ahead ₁, L ₂, L ₃Be connected at 1,2,3, constitute the place ahead testing circuit.4,7,8 binding posts of its base then are connected at 4,7,8 with three-phase circuit W, U, the V at A.C. contactor KM rear, constitute the rear testing circuit.5,6 binding posts of its base are serially connected in the normally opened contact of relay K A1 in the control loop of threephase motor.QS is a Three-phase knife switch, FU ₁, FU ₂Be fuse, FR is a thermal relay, SB ₂Be starting button, SB ₁Be stop button, M is a threephase motor.

As seen from Figure 2, wiring board of the present utility model is made up of DC power supply circuit, line voltage sample detecting and regulating circuit, front and back voltage sample testing circuit and integrated voltage comparator binary channels controlling output circuit.Described dc power electric routing transformer T, rectifier bridge V ₁₃～V ₁₆With filter capacitor C ₁With regulator block JC ₃Constitute; Line voltage sample detecting regulating circuit is by integrated voltage comparator JC ₂, potentiometer R ₉, resistance R ₈, R ₁₀～R ₁₃Voltage-stabiliser tube V ₁₇Constitute; Described forward and backward side's voltage sample testing circuit is separately positioned on the forward and backward side of A.C. contactor, and the place ahead circuit has misphase and phase failure measuring ability, and it is by resistance R ₁～R ₄, diode V ₁～V ₄And capacitor C ₂～C ₄Constitute; The rear circuit only have phase failure measuring ability it by capacitor C ₅～C ₇, diode V ₁₀, V ₁₁Constitute; The two controlling output circuit of described integrated voltage comparator are by integrated voltage comparator JC ₁With triode V ₉, relay K A1, KA2 constitute, homophase, inverting input c, d respectively with triode V ₅Collector electrode link to each other JC with base stage ₁Gating end ST and triode V ₉Collector electrode link to each other base stage and A.C. contactor KM rear voltage sample testing circuit output diode V ₁₀Link to each other.JC ₁Output links to each other with the switch of relay K A2, and the KA2 normally opened contact links to each other with KA1 coil one end, and KA1 coil two ends are shunt capacitance C also ₈, the normally opened contact of KA1 switch is serially connected in the control loop of threephase motor M.

Light-emitting diode V ₇One end series resistor R ₇, other end ground connection; Light-Emitting Diode V ₆One end links to each other with d, the other end and voltage-stabiliser tube V ₁₂, resistance R ₆Link to each other.

Operation principle of the present utility model is as follows:

When line voltage just often, JC ₂The voltage of input a is higher than the burning voltage that another input b sets, JC ₂Forward is saturated, output voltage+V _c, relay K A2 gets electronic work, makes the KA2 coil electricity, and the KA2 normally opened contact is connected JC ₁Output is the KA1 coil, if do not have the phase failure, misphase generation, then JC this moment again ₁Output current is given the KA1 coil, makes the KA1 normally opened contact connect the Motor Control loop, makes normally opened contact 5,6 closures, and motor can starting operation, light-emitting diode V at this moment ₇Circuit is connected, and green indicating lamp is bright.

When the line voltage reduction arrives predetermined under-voltage protection voltage, JC ₂The voltage of input a is lower than the voltage of another input b, JC ₂Output voltage is zero.The KA2 coil losing electricity also cuts off the power supply KA1, and its normally opened contact 5,6 resets, and cuts off the Motor Control loop, and motor is cut off stall because of power supply.This moment light-emitting diode V ₁₈Circuit is connected.Show that under-voltage orange indicating light is bright, green indicating lamp extinguishes simultaneously.Regulator potentiometer R ₉Can change the set point of under-voltage protection voltage.

KM the place ahead voltage sample testing circuit when normal power supply, inverter V ₅Input low level, output high level, JC at this moment ₁Forward is saturated, output voltage+V _c, KA1 gets electronic work, normally opened contact 5,6 closures in the Motor Control loop, and M gets ready for starting motor; During unusual power supply (phase failure or misphase), V ₅Input high level, output low level JC ₁Negative sense is saturated, and output voltage is zero, and KA1 must not be electric, and the normally opened contact 5,6 of KA1 disconnects motor M fail to start in the control loop.This moment red led V ₆Bright, green indicating lamp V ₇Extinguish.

KM rear voltage sample, testing circuit behind motor starting just immediately electric work, during normal power supply (the not phase failure of rear), voltage sample, control circuit output low level, triode V ₉End, gating end ST is a high level, at this moment JC ₁Comparing function is arranged, V ₅End JC ₁In-phase input end is a high level, and voltage ratio has+V after.Output; Disconnected any phase time, voltage sample detection circuit output high level, triode V ₉Conducting, gating end ST is a low level, causes JC ₁Output voltage is a null value, and KA1 must not be electric, and its normally opened contact 5,6 resets, and cuts off control circuit, and motor M power supply is cut off.

Light-emitting diode V ₇Indicator light when (green) is normal power supply, V ₅(phase failure, misphase) malfunction indicator lamp when (redness) powers unusually for KM the place ahead, V ₁₈Malfunction indicator lamp when (orange) is under-voltage power supply.Be simplified structure, adopted the tripod double color luminotron to replace V ₇And V ₁₈Two indicator lights have been realized three kinds of operating mode indications.

Prototype test shows that the utility model discloses the function that has also obtained under-voltage protection the original function of utility model except that keeping.

Claims

1. under-voltage phase failure fault-phase protection device, it is made of base, housing and the wiring board with a plurality of binding posts, it is characterized in that: A.C. contactor KM the place ahead network voltage detection and regulating circuit are by integrated voltage comparator JC ₂, potentiometer R ₉, voltage-stabiliser tube V ₁₇And resistance R ₈, R ₁₀～R ₁₃Constitute; KM the place ahead voltage sample testing circuit is by resistance R ₁～R ₄, capacitor C ₂, C ₃With diode V ₁～V ₄Constitute; KM rear voltage sample testing circuit is by capacitor C ₅～C ₇, diode V ₁₀, V ₁₁Constitute; Integrated voltage comparator JC ₁Output circuit is by JC ₁, triode V ₉, relay K A1, KA2 constitute, the JC1 output links to each other with the switch of KA2, the KA2 normally opened contact links to each other with the KA1 coil, KA1 switch normally opened contact is serially connected in the control loop of threephase motor M.

2. it is characterized in that by the described under-voltage phase failure fault-phase protection device of claim 1: A.C. contactor KM the place ahead is provided with network voltage detection and regulating circuit, and it is by integrated voltage comparator JC ₂, potentiometer R ₉, voltage-stabiliser tube V ₁₇And resistance R ₈, R ₁₀～R ₁₃Constitute, the big I of line voltage when realizing under-voltage protection is by potentiometer R ₉Regulate and determine.

3. it is characterized in that by the described under-voltage phase failure fault-phase protection device of claim 1: A.C. contactor KM the place ahead and rear are provided with the voltage sample testing circuit respectively, and its place ahead circuit is by the resistance R that can detect the misphase and the phase failure ₁～R ₄, capacitor C ₂, C ₃Rectifier bridge V with signal voltage ₁～V ₄Constitute, its rear circuit is by the capacitor C that can detect the phase failure ₅～C ₇, triode V ₁₀, V ₁₁Form.

4. it is characterized in that by the described under-voltage phase failure fault-phase protection device of claim 1: integrated voltage comparator JC ₁Output links to each other with the switch of relay K A2, and the KA2 normally opened contact links to each other with relay K A1 coil, and KA1 switch normally opened contact is serially connected in the control loop of threephase motor M.