SU1677832A1 - Device for starting phase-wound induction motor - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drives for drawing mills, conveyors and lifting machines. The purpose of the invention is to increase the reliability of the device. When the control button 33 is turned on, the line contactor is turned on, the mains voltage is applied to the stator of the motor 1, and a current bounded by the second group of 14 three-phase starting resistors flows through its windings. In this case, in the rotor circuit of the relay with voltage coil 15 is turned on, but in the power circuit there is no current, since capacitors 34, 35, 36 limit the opening angle of the thyristors of switch 2. As a result of this, the occurrence of electromagnetic dynamic moments is eliminated. The thyristors of switch 2 are opened depending on the load, so that a smooth increase in starting torque and engine speed 1, the choice of kinematic gaps and the exclusion of dynamic shocks are ensured. When the maximum moment is reached and the thyristors of the switch 2 are fully opened, the moment of the motor 1 is limited by the resistances of the resistors in the rotor and stator circuit. 1 il. SO with

Description

The device relates to electrical engineering and can be used in electric drives of drawing mills, conveyors and lifting machines.

The purpose of the invention is to increase the reliability of the device.

The drawing shows a diagram of the device.

A device for starting an asynchronous motor 1 with a phase rotor contains a three-phase thyristor switch 2, a first group of 3 three-phase starting resistors, a distributor of 4 pulses connected by its outputs to control electrodes of a three-phase switch 2, a line contactor with a coil 5 and four make contacts 6, 7, 8, 9, time relay with coil 10 and closing contact 11, buttons 12, 13 Stop and Start. The device also contains a second group of 14 three-phase starting resistors, a voltage relay with a coil 15 and an opening contact 16, an intermediate relay with a coil 17 and four closing contacts 18, 19, 20, 21, a first bypass contactor with a coil 22 and four making contacts 23, 24, 25, 26, second shunt contactor with coil 27 and three closing contacts 28, 29, 30, threshold element 31, adjustable resistor 32, control button 33, three capacitors 34, 35, 36, shunt O

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The thyristors are controlled by three-phase thyristor switch 2, three-phase diode half-bridge 37, the common output of which is connected to one output of the threshold element 31 and to one output of the first closing contact 18 of the intermediate relay, the other output of which is connected to the input of the distributor 4 pulses and to one the output of the adjustable resistor 32, the other output of which is connected to another output of the threshold element 31. The outputs of the three-phase thyristor switch 2 are connected to the same terminals of the first group of three three-phase other starting resistors, the other terminals of which are designed to connect to the rotor winding pins of the electric motor 1, the phase terminals of the stator winding of which are connected to the second group of 14 three-phase starting resistors, the other terminals of which are connected to the same pins of the first, second and third contact contacts 6, 7, 8 a line contactor, the other terminals of which are intended to be connected to a power source. The first, second and third resistors of the second group of 14 three-phase starting resistors are shunted by the first, second and third make contacts, 28, 29, 30 of the second bypass contactor, respectively. The first, second and third pins 23, 24, 25 of the first bypass contactor are designed to short the rotor winding phases of the electric motor 1. Three inputs of a three-phase diode half bridge 37 are connected to other terminals of a resistor of the first group of 3 three-phase starting resistors. The coil 15 of the voltage relay with its terminals is intended to be connected to the two phase terminals of the rotor winding. One terminals of coils 5, 17, 22, 27, 10 of a linear contactor, an intermediate relay, the first and second shunt contactors and a time relay are combined to connect a power source to one phase, the other output of the coil 5 of a linear contactor is connected to one output of a control button 33 shunted by the second closing contact 19 of the intermediate relay, another output of the control button 33 is connected to one output of the button 12 Stop and pressing the Start button 13 shunted by the third closing contact 20 of the intermediate relay. The other terminal of the Start button 13 is connected to another terminal of the coil 17 of the intermediate relay. Another pin of the button 12 Stop and one pin of the fourth make contact 21 of the intermediate relay

combined and intended to be connected to a different phase of the power source. Another output of the fourth make contact 21 of the intermediate relay, one

the opener pins 16 of the voltage relay, the fourth make contact 26 of the first bypass contactor, and the closing contact 11 of the time relay are combined. Another pin of the breaking contact 16 of the voltage relay is connected via the fourth closing contact 9 of the line contactor to another terminal of the coil 22 of the first bypass contactor, another terminal of the coil 10 is connected to another terminal of the fourth closing contact 26 of the first bypass contactor. Another terminal of the coil 27 of the second bypass contactor is connected to another terminal of the closing contact 11 of the time relay.

The device works as follows. ,

When the control button 33 is turned on, the line contactor is switched on and on the stator

5, the motor 1 is supplied with a network voltage and a current is flowing through its windings limited by the second group of 14 three-phase starting resistors. At the same time, in the rotor circuit of the relay (15) the voltage is switched on, but in the power circuit

0, there is no current, since the capacitors 34, 35, 36 limit the opening angle of the thyristors of the switch 2. As a result of this, the occurrence of electromagnetic dynamic moments is eliminated. The thyristors of the switch 2 are opened depending on the load, so that a smooth increase in the starting torque and the speed of the engine 1, the choice of kinematic gaps and the exclusion of dynamic

0 beats.

When the maximum moment is reached and the thyristors of the switch 2 are fully opened, the moment of the motor 1 is limited by the resistances of the resistors in the rotor circuit

5 and the stator. At the same time, the speed of the motor 1 rises to the refueling one and is determined by the position of the adjustable resistor 32 and the threshold element 31. When the parameters of the adjustable resistor 32 change.

0 of the threshold element 31, the engine characteristic may vary.

To implement the overclocking mode, the Start button 13 is turned on. As a result, an intermediate relay 17 with a carcass and a line contactor is turned on. A threshold element 31 and a resistor 32 are derived from the control circuit. Acceleration of engine 1 at the initial moment is similar, and then the rotor EMF decreases so much that the voltage relay

coil 15 shuts off and closes its contact 16 in the circuit of coil 22 of the first bypass contactor. As a result, it turns on and shunts the first group of 3 three-phase starting resistors in the rotor circuit and the motor accelerates according to a characteristic determined by the resistance of the second group 14 of three-phase starting resistors in the stator circuit. At the same time, the first bypass contactor closes its contact 26 of the time relay circuit with coil 10 and, with an exposure time determined by the acceleration time of motor 1, switches on the second bypass contactor and the motor goes to natural characteristic, acceleration of motor 1 ends.

Thus, this device provides a smooth increase in speed with an increased starting torque in the initial stage of acceleration, adjustable charging speed and acceleration to the nominal speed with a minimum number of acceleration steps and a decrease in the rate of change in starting torque. All this allows to increase the reliability of the device.

Claims (1)

Apparatus of the Invention A device for starting an induction motor with a phase-rotor, containing a three-phase thyristor switch, the first group of three-phase starting resistors, a pulse distributor connected by its outputs. time with a coil and a closing contact, the Stop and Start buttons, characterized in that, in order to increase reliability, a second group of three-phase start-ups are entered into it x resistors, voltage relay with coil and opening contact, intermediate relay with coil and four closing contacts, first bypass contactor with coil and four closing contacts, second bypass contactor with coil and with three closing contacts, threshold element, adjustable resistor, control button , three capacitors, shunt control thyristor transitions of a three-phase thyristor switch, a three-phase diode half-bridge, the common output of which is connected to one output of the threshold el ment and to one terminal of the first switching contact of the intermediate relay, the other terminal which is connected to the sxo.av of the pulse pulse, and to one pin of an adjustable resistor, the other pin of which is connected to the other pin of the threshold Element, at the top of the PREHAZNY ™ RI $ R-ny commutator penklpchen x; ,, the conclusions of the first trehmotOUPLOADS starting resislops, l shgot. which intended - .. .c 0 degenerates winding rotsr from sk.ros, egl, and% e- jifi, one output to the second of the ipjn-ipys of starting resistoresch orech e no is under the iodine phase of 4.0 m of winding, others output from VYO / GM r ,, JBO v ITOO AND The third end of the SCG is the main contact of the contact Ectooa, the other BL-SGUJ of the common ones is intended for the power supply to the power supply first, second and other. second resistors of the second three-phase 1, group of starting resistors gashun.rov-en1 respectively the first BIODL ..; and the third one closing the second shunt con-hc | 0rz first, the second h ip5 tmi closure of the congruent of the sh-first shunt of the cong. dr tim 0 pins resisyushchech pstzy Fahfazyuyu group, the coil relz nachr h CHOIR / I.I conclusions intended for under; sho, ecig- to two phase z-vodz oo. cc .OIKH, one of the conclusions of the catac ek linear co., -hicht5 ra intermediate peae, primary.1. The sTopcio shunt contactors of the time relay are integrated and intended for connection to a power supply, the output terminal of the linear terminal coil is connected to one output button of the j button of the control panel, the second closing button is connected to the solenoid relay, the other output of the control button is connected to one withdrawal kiosks Stop and 5 Start buttons, shuntiro & o tea with the third closing contact of the Progressive Intermediate Relay, another output the Start button is connected to another output K iyiLk of the Intermediate relay, another one of the Stop button 0 and one output of the fourth make contact of the intermediate relay are combined and intended to be connected to another phase of the power supply, the other output of the fourth make contact 5 intermediate relays, one output of the open contact of the voltage relay, the fourth closing contact of the first bypass contactor and the closing contact of the time relay are combined, another output of the open contact of the relay voltage through the fourth make contact of the line contactor is connected to another coil lead of the first bypass contactor, another coil lead of the time relay is connected to another pin the fourth make contact of the first bypass contactor, another coil lead of the second bypass contactor is connected to another time switch contact of the time relay.