SU1259455A1 - Device for braking three-phase induction motor - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drives of conventional mechanisms. The aim of the invention is to increase the reliability of the device by eliminating the possibility of self-starting an induction motor after braking. In the device, a speed control relay 13 is installed on the shaft of the induction motor 1, the contact 14 of which is located in the circuit of the thyristor 19, which opens for the time the motor rotates to the left or to the right. The device circuit provides engine 1 deceleration with de-energization. When motor 1 reaches zero speed, contact 14 of speed control relay 13 opens, coil 10 loses power, and thyristor 19 is turned off. 1 il. in (L ts9 SL CO 1 ate SP

Description

one

The invention relates to electrical engineering and can be used in electric drives of general industrial mechanisms.

The purpose of the invention is to increase the reliability of the device by eliminating the possibility of the self-starting of the induction motor after braking

The drawing shows a diagram of the proposed device.

A device for braking a three-phase asynchronous motor 1 contains power contacts 2 contacts

torus to the left and power contacts 3 of the contactor to the right in the phases of the stator winding of the induction motor t, knop Stop, 4 one output of which is connected with the phase of the stator winding of asynchronous engine 1, and the other output with one output of the control button 5 to the left and one output of the button 6 controls to the right, shunted by the corresponding closing contacts 7 and 8 to the left and to the right. The coil 9 of the contactor to the left and the coil 10 of the contactor to the right are connected by one output, the other lead of the coil 9 is connected to one output of the contacting contact 11 of the contactor to the right, the other lead of the coil 10 is connected to one output of the disconnecting contact 12 of the contactor to the left. The device also contains a speed control relay 13 mounted on the same shaft with the rotor of the asynchronous motor 1, with closing contacts 14 and 15, one terminals of which are combined, the third closing contact 16 of the contactor to the left, the fourth contact 17 of the contactor to the right, three diodes

18, thyristor 19, four resistors 20-23, command device with four contacts 24-27. The common point of one of the pins of the first 20 and second 21 resistors is provided with a clamp for connecting the power supply to zero and connected to one coil pins.

9 and 10, the other terminals of the first 20 and second 21 resistors are connected to other terminals of the closing contacts 14 and 15 of the speed control relay 13, respectively, the common point of which is through the third resistor 22 connected to the cathode of the thyristor 19, the anode through the fourth resistor 23 and in parallel connected pins 16 and 17 are connected to the thyristor control electrode

19.Anodes of three diodes 18 are connected

0

20

The stator winding phases of the asynchronous motor 1 and the cathodes of diodes 18 are combined and connected to the thyristor anode 19. / The other output of the control button 5 to the left is through the first contact 24 of the controller connected to another output of the contact 11 of the contactor right, another output of the control button 6 Right 1

through the second contact 25 of the control unit is connected to another output of the disconnecting contact 12 of the contactor to the left, another output of the first resistor 20 through the third contact 5 26 of the control unit is connected to another output of the disconnecting contact 12 of the contactor to the left, another output of the second resistor 21 is connected to the other contact 27 By opening the contact 11 of the contactor to the right.

The device works as follows.

The command device selects the required direction of rotation of the asynchronous motor 1, for example, it is turned to the left. At the same time, contacts 24 and 26 of the control device are closed, and contacts 27 and 25 are opened. When the control button 5 is pressed to the left, the coil 9 of the contactor to the left is energized, its contacts 2, 7 and 16 are closed, contact 12. The shaft of the induction motor 1 starts to rotate left, the speed control relay 13 begins to rotate with it, resulting in its contact 14 closes. The current rectified by diodes 18 passes through a resistor 23, a closed contact 16, a thyristor control transition 19, a resistor 22, a closed contact 14 of the control relay 13

speed, resistor 20 to the neutral wire of the power supply. Thyristor 19 opens. To stop the engine 1, they press the Stop button 4. At the same time, the coil 9 of the contactor loses power to the left, contacts 2, 7 and 16 are opened and contact 12 is closed. Circuit: diodes 18, thyristor 19, resistor 22, contact 14 of speed control relay 13, contact 26 of the controller, contact 12 of the contactor to the left, the coil 10 of the contactor is supplied to the right and its contacts 3, 8 and 17 are closed, and contact 11 is opened. Inhibition occurs

engine 1 pro-inclusion. When reaching d1-; ng, pleyu i zero frequency m; rotation contact 14 of the speed control relay 13 is open, the switch 10 loses power, the thyristor is turned off. The circuit is reset to the initial state. To ensure rotation of the engine 1 to the right, the control unit is moved to the right. At the same time, contacts 27 and 25 are closed and contacts 24 and 26 are opened. Press the control button 6 to the right, the coil 10 of the contactor receives power to the right, its contacts 3, 8 and 17 are closed, its contact 11 is opened. The shaft of the induction motor 1 starts to rotate to the right, it closes pin 15 relay 13 speed control. According to the circuit: diodes 18, resistor 23, pin 17, control electrode of the thyristor 19, resistor 22, pin 15 of the speed control relay, resistor 21, the neutral wire of the power supply source passes current. Thyristor 19 opens. To stop the motor 1, they press the Stop button 4. The contactor 10 wheel loses power to the right, its contacts 3, 8 and 17 are opened, contact 11 is closed. Circuit: diodes 18, thyristor 19, resistor 22, contact 15 of speed control relay 13, contact 27 of the commander, contact 11 of the contactor to the right receives power to the coil 9 of the contactor to the left and its contacts 2, 7 and 16 are closed, contact 12 is opened. Engine 1 is braked by opposition. When engine speed 1 reaches zero speed, contact 15 of the speed control relay opens, coil 9 loses power, the thyristor turns off

Thus, the reliability of operation of the device is increased, since the possibility of self-starting an asynchronous motor is excluded. If the operator manually turns the motor shaft, the speed control relay closes one of its contacts, but coils 9 or 10 contactors do not receive power, since buttons 5 and 6 are not pressed, and thyristor 19 is de-energized, as contacts 16 and 17 are open, t . safety is also ensured.

Claims (1)

Invention Formula 0 five about five 0 five A device for braking a three-phase asynchronous motor containing the power contacts of the contactors left and right in the phases of the stator winding of the induction motor, the Stop button, one pin of which is connected to the phase of the stator winding of the induction motor, and the other pin with one of the left and right control buttons of the asynchronous motor corresponding to the first and second closing contactors of the contactors left and right, the coils of which are united in one way or the other and connected to the same terminals of the contact opening contactors A right-and-left ditch, respectively, a speed control relay, mounted on one shaft with an induction motor rotor, with two make contacts, one of whose terminals are combined, the third and fourth contact contacts left and right, respectively, characterized by In order to increase reliability, three diodes, a thyristor, four resistors, a four-contact control device were inserted into it, a point of one of the first and second resistor outputs is equipped with a clamp for connecting the power supply to zero and is connected to one pins of contactors coils, to the left and right other conclusions the first and second resistors are connected to the other terminals of the closure contacts of the control relay respectively, the common point of some of the leads through the third resistor is connected to the thyristor cathode, the anode of which through the fourth resistor and the third and fourth contactors of the contactors connected in parallel to the left and right are connected to the control electrode of the thyristor, the anodes of three diodes are connected to the stator windings of the asynchronous motor , the cathodes of the diodes are combined and connected to the thyristor anode, the other output of the control button to the left is connected via the first contact of the controller with another pin of the contactor opening contact to the right, another pin of the control button to the right via the second contact of the controller 512594556 connected to another output of the opening contact of the contactor to the left, the other contact of the contactor to the left, the output of the second resistor through the alternate output of the first resistor through the true contact of the controller, the third contact of the controller connects to the other output of the opening contactor to the right.