CN86200766U

CN86200766U - General phase break protector of three-phase electric moters

Info

Publication number: CN86200766U
Application number: CN 86200766
Authority: CN
Inventors: 王祖凡
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-01-21
Filing date: 1986-01-21
Publication date: 1987-11-11

Abstract

The utility model discloses a general phase break protector for three-phase electric motors, belonging to an emergency protective device for electric motors. Protective signals are transmitted by resistors, and a direct current relay or a direct current electromagnet is taken as an actuating element. When the malfunction of phase break occurs in any one phase of a three-phase electric motor, signals can be output immediately to actuate the direct current relay to switch off or the direct current electromagnet to lose magnetism, and accordingly, the transient phase break protection of the electric motor can be realized. The utility model has the advantages of simple structure, high reliability, low cost and small size. The general phase break protector is suitable for matching with three-phase electric motors with the power range of 0.05-1000KW and the voltage of 360-440V. The general phase break protector can also protect motors which are controlled by a three pole switch.

Description

General phase break protector of three-phase electric moters

The utility model relates to the phase failure protector that a kind of three-phase alternating-current motor is promptly protected usefulness.

The open phase protection of existing three-phase alternating-current motor has variety of way; the switching circuit that for example adopts current transformer difference input signal to form for transistor (or diode); when the electric current of three phase mains normal supply motor; the transistor switch conduction; relay adhesive and contactor are sold mutually,, forced transistor to end when circuit breaks down one when disconnecting mutually; relay discharges, and cuts off main control loop.But when changing a less load, current transformer is paid the induced signal on limit will be less than the saturation voltage of transistor, and transistor will cause executive component out of control and malfunctioning with regard to cisco unity malfunction; In addition, must connect different current transformers to the load of different capacity, can not generalization.Adopt electric capacity three-phase equilibrium sampling mode, the sampled voltage imbalance can be sent the protection instruction during phase failure, but the electric capacity volume is big, and the cost height is very uneconomical.Simultaneously, adopt above-mentioned open phase protection mode all can not carry out protection, cause motor to leak and protect the directly actuated motor of three-pole switch.

Task of the present utility model provides two kinds of not only economy but also the general open phase protection that can carry out transient protection to any threephase motor of different capacity; also can give open phase protection to the threephase motor of three-pole switch across-the-line starting control; and volume is little, can be installed in the open-phase protection circuit in the motor load more than 0.6 kilowatt.

The first kind of solution that the utility model proposes is to adopt the phase failure protector of direct current relay control, finished by following mode: adopt three resistance output control signals, make executive component relay and main control circuit interlocking under crystal diode cooperates.Promptly connect a resistance respectively every the going up mutually of threephase motor, when having electric current to pass through on the resistance, the crystal diode output current orders about direct current relay adhesive and A.C. contactor interlocking, does not cut off power supply, and motor runs well.When disconnecting mutually, its resistance no current passes through when a certain, the output of crystal diode no current; therefore the AND gate switch of three direct current relay compositions cuts out; force the relay of this phase to discharge and disconnect, cut off the electricity supply, realize open phase protection with A.C. contactor interlocking contact.

Referring to Fig. 1, all fronts route overcurrent protector RD ₁, RD ₂, RD ₃, A.C. contactor JC, control button HA ₁, HA ₂, motor Dy, resistance R ₁, R ₂, R ₃, rectifier diode D ₁, D ₂, D ₃, D ₄, D ₅, D ₆, direct current relay J ₁, J ₂, J ₃Form with potentiometer W.Overcurrent protector RD ₁, RD ₂, RD ₂Be connected on the three-phase alternating-current supply A.C. contactor JC and overcurrent protector RD respectively ₁, RD ₂, RD ₃Polyphone, motor Dy three-phase inlet wire post is connected resistance R with the fixed contact of A.C. contactor three main contactss ₁, R ₂, R ₃Be connected on respectively on the three-phase inlet wire binding post of motor Dy.Crystal diode D ₁, D ₂, D ₃An end be connected on resistance R respectively ₁, R ₂, R ₃On, the other end is connected on direct current relay J respectively ₁, J ₂, J ₃On, crystal diode D ₄, D ₅, D ₆An end be connected on direct current relay J respectively ₁, J ₂, J ₃On, the other end is connected on respectively on the potentiometer W, and potentiometer W three lug plates are connected to J respectively ₁, J ₂, J ₃On, starting button HA ₁, HA ₂Be connected on respectively on power supply phase line and the A.C. contactor JC.

When pressing starting button HA ₁The time, A.C. contactor JC energising, motor Dy starting, three divider resistance R ₁, R ₂, R ₃Electric current output is all arranged, respectively through crystal diode D ₁, D ₂, D ₃, D ₄, D ₅, D ₆Make direct current relay J after the rectification ₁, J ₂, J ₃Adhesive, J ₁Normally opened contact 1 and 2, J ₂Normally opened contact 3 and 4, J ₄Normally opened contact 5 and 6 gang up composition " go into " gate circuit and with A.C. contactor JC interlocking, motor Dy runs well.When disconnecting mutually, for example A disconnects mutually, the divider resistance R that this phase connect when a certain ₁No current passes through, crystal diode D ₁With D ₄No current output, direct current relay J ₁Discharge, disconnect 1 and 2 break of contact power supplys,, motor is protected so A.C. contactor cuts off three phase mains.

Size of current on the executive component direct current relay is adjusted by adjustable resistance W, preferably makes electric current reach 1.1 times of direct current relay coil attract currents.Voltage on the direct current relay is by R ₁, R ₂, R ₃Adjust.Under the situation that guarantees direct current relay normal working voltage value, select the voltage partial pressure value, resistance R ₁, R ₂, R ₃Power equal adjust power and the potentiometer W and the crystal diode institute consumed power sum of direct current relay.Resistance R ₁, R ₂, R ₃The resistance and the power of dividing potential drop are calculated as follows:

R _1～3=(V _Phase)/(11I _J), N=((I ² _J+ I ² _D+ ((I ² _W)/3)) * R

In the formula: R _1～3-divider resistance

V _Phase-ac phase voltage

I _J-direct current relay attract current

I _WElectric current on the-potentiometer

I _DElectric current on the-diode

N-divider resistance power.

The second kind of solution that the utility model proposes is to adopt the phase failure protector of DC electromagnet control; finish by following mode: adopt three signal resistance balanced voltage sampling modes; when circuit just often, the resistance voltage balance, no signal is sent; transistor ends; the electromagnet coil no current passes through, and can not inhale to start the claw of switch, and hand switch can not be realized normally open; electric current constantly flows through hand switch, and motor is run well.When certain disconnects mutually, just there is a resistance no current to pass through, the resistance voltage balance is destroyed, phase failure sampled voltage imbalance is promptly sent instruction opens transistor switching circuit; Make the electromagnetic actuation claw, hand switch recovers former often to be opened, and three phase mains disconnects, and realizes the motor open-phase protection of three-pole switch control.

Referring to Fig. 2, the manual self-lock switch KH of route master control completely, signal resistance R ₁, R ₂, R ₃, signal output transformer B ₁, by filter capacitor C ₃, C ₄, crystal diode D ₁Regulating resistor W forms rectification circuit, by voltage-stabiliser tube DW ₁Filter capacitor C ₂, resistance R ₄, R ₆Transistor BG ₁, BG ₂The delay switch circuit of forming, executive component electromagnet D _TWith diode D ₂, power transformer B ₂Form with transistor bridge-type rectification circuit.By the manual self-lock switch of master control be serially connected with within the three-pole switch and motor on, signal resistance R ₁, R ₂, R ₃Be connected to respectively on the three phase mains, the other end is connected to signal output transformer B by the F point ₁On the former limit, the former limit of its signal output transformer one end ground connection (center line) is paid edge joint in by crystal diode D ₁, filter capacitor C ₃, C ₄On the rectification circuit of forming, direct current signal after rectification, by potentiometer W to by voltage-stabiliser tube D _W, filter capacitor C ₂, resistance R ₄, transistor BG ₁, BG ₂The delay switch circuit of forming.The protective circuit power supply is by power transformer B ₂Provide with transistor bridge-type current rectifying and wave filtering circuit.

Referring to Fig. 2, when pressing the button HA ₁The time, contactor JC energising, motor starting, three phase mains are respectively by signal resistance R ₁, R ₂, R ₃To signal transformer B ₁Former limit to center line O(center line can be the direct ground connection of connecting to neutral formula), when the three phase mains balance, the current potential that F is ordered is zero, so the former limit of signal transformer does not just have electric current, transistor BG at this moment ₁, BG ₂Can not get signal, be in cut-off state, be equivalent to open circuit, electromagnet D _TCoil in do not have electric current to be failure to actuate by claw, manually self-lock switch KH can not recover former off-state, electric current passes through, motor runs well.

When arbitrary when cutting off the power supply mutually in the two-phase power supply, because three-phase imbalance, F point current potential just is higher than zero potential, signal transformer B ₁Former limit just have electric current to pass through, thereby pay the limit and produce induced voltage.Induced voltage is through crystal diode D ₁Rectification, capacitor C ₃After the filtering, pass through voltage-stabiliser tube D again _W1Voltage stabilizing just becomes direct voltage more stably, and this voltage is through filter capacitor and resistance R ₄After the time-delay, add to transistor BG ₁Base stage on (transistor BG wherein ₁And BG ₂Form combination and amplify, make it enough power and promote electromagnet D _TWork reliably), transistor BG at this moment ₁, BG ₂Conducting, electromagnet D _TAction, manually the self-lock switch claw discharges, and manually self-lock switch KH restores, and contact chip disconnects, and cuts off the three phase mains that three-pole switch leads to motor, has realized open phase protection.After open phase fault is got rid of, hand switch KH pressed self-locking after, the three-pole switch that closes, motor can continue operation again.

If motor power (output) less (below 5 kilowatts) can not adorned three-pole switch and other switch, three phase mains directly is connected to manual self-lock switch KH line-start motor.When shutting down, press K switch ₁Get final product.If the control transform and its application in electromotor load power is bigger, available the utility model is joined magnetic switch control and protection motor again.Transistor BG ₁, BG ₂Working power be by transformer B ₂(also can use the divider resistance step-down) after the step-down, make bridge rectifier through four crystal diodes, again through resistance R ₅, capacitor C ₁Filtering and obtaining.It should be noted that transformer B ₂The end of incoming cables on former limit must be connected on hand switch KH with on the interior circuit, can not be identical when equipped contactor with the contactor magnetic coil, so as after shutdown transformer B ₂Also quit work.

The advantage of the phase failure protector of the direct current relay control that the utility model proposes is: owing to adopted current-limiting resistance, the non-ferrous metal of making relay is reduced in a large number, owing to adopt the crystal diode rectification, the efficient of relay is significantly improved, volume greatly reduces; If the control motor can be installed in its phase failure protector in the terminal box of motor person more than 0.6 kilowatt, do not take the locus of motor control system, also can improve the useful life of motor.

The advantage of the DC electromagnet control phase failure protector that the utility model proposes is: because the manual self-lock switch of employing magnet control can be to its phase failure of motor reliable protection of three-pole switch across-the-line starting; also can cooperate with other magnetic switch; control jumbo motor: owing to adopted transistor signal amplification circuit and delay circuit; can press at light current, the work reliably and with long-term of little current conditions, and do not contain any misoperation.

The utility model suitable power scope is 0.05～1000 kilowatt, and voltage range is the supporting use of 360～440 volts motor.

Brief description of drawings:

Fig. 1 is the phase failure protector schematic diagram of the utility model direct current relay control

Fig. 2 is the phase failure protector schematic diagram of the utility model DC electromagnet control.

Claims

1, a kind of threephase motor is promptly protected the phase failure protector of usefulness, comprises direct current relay J ₁, J ₂, J ₃, potentiometer W is characterized in that having three signal resistance R ₁, R ₂R ₃, by on motor three-phase inlet wire binding post, six crystal diode D are arranged respectively ₁, D ₂, D ₃, D ₄, D ₅, D ₆, its crystal diode D ₁, D ₂, D ₃One end is connected on signal resistance R respectively ₁, R ₂, R ₃On, the other end is connected on direct current relay J ₁, J ₂, J ₃On, crystal diode D ₄, D ₅, D ₆One end is connected on direct current relay J respectively ₁, J ₂, J ₃On, the other end is connected on the potentiometer W.

2, a kind of threephase motor is promptly protected the phase failure protector of usefulness, comprises signal transformer B ₁, power transformer B ₂, electromagnet executive component circuit, transistor bridge-type rectification circuit is characterized in that having signal resistance R ₁, R ₂, R ₃, one terminates on the three phase mains, and the other end is connected on signal transformer B ₁Former limit, at signal transformer B ₁Pay on the edge joint by capacitor C ₃, C ₄, crystal diode D ₁, on the rectification circuit that potentiometer W forms, potentiometer W connects by voltage-stabiliser tube D _W, capacitor C ₂, resistance R ₄, transistor BG ₁, BG ₂The delay switch circuit of forming.

3,, it is characterized in that electromagnet executive component circuit is by electromagnet D according to the described phase failure protector of claim 2 _T, the manual self-lock switch KH of master control, crystal diode D ₂Form, the manual self-lock switch KH of its master control is connected on the three phase mains electromagnet D _TBe connected on the manual self-lock switch KH of master control, control by delay switch circuit.