SU1283921A1 - Device for braking induction electric motor by plugging - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control electric drives of general industrial mechanisms. The aim of the invention is to simplify the device. The purpose of the invention is provided by eliminating the possibility of spontaneous starting of the engine when turning the shaft of the electric motor, as well as rotating the rotor of the electric motor in opposite

Description

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after the end of the braking process, by creating an additional supply circuit for the coils 12 and 15 of the intermediate relay and coils of the contactors 18 and 19 through the contacts 8 and 9 of the relay 7 of the speed control and in parallel connected contacts 283921

allows the motor to be decelerated by stopping the motor, after which contact 8 (or 9 depending on the direction of rotation) of the contactor and the intermediate relay is opened, and open contacts 13 and 16 create an additional open circuit. 1 il.

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The invention relates to electrical engineering and can be used to control electric drives of common motorized mechanisms.

The aim of the invention is to simplify the device.

The drawing shows a schematic diagram of a device for braking by the inhibition of a three-phase asynchronous electric motor.

The device for counter-switching inhibition of a three-phase asynchronous motor 1 contains three current-limiting resistors 2, 3 and 4, one terminals of resistors 2 and 3 through coils 5,6 of thermal relays are connected to two phase terminals of the stator winding of motor 1, the third phase output of which is connected to one a third current; a limiting resistor 4; a relay 7 controlling the speed of an electric motor 1 with two closing contacts 8 and 9 and two opening contacts 10 and 11; the first intermediate relay with a coil 12 and with two closing 13,14, the second intermediate relay with coil 15 and with closing contacts 16 and 17, coils 12 and 15 are connected by one pins and connected to one pins of coils 18 and 19 of the Forward and Back contactors, the other pins of which are connected to one open switch pins 20 and 21 other contactors Back and Forward, button 22 Start forward, button 23 Start back, buttons 22 and 23 are bridged with closing contacts 24 and 25 of the Forward and Back contactors, one terminal of buttons 22 and 23 are combined and through button 26 Stop are provided with a clip for connect to first mains supply, shunt contactor with coil

21 n with three locking contacts with 1 pins 28,29 and 30, shunting current-limiting resistors 2,3 and 4, another output of the current-limiting resistor 2 is connected to the combined first terminals of the closing contacts 31 and

32contacts Forward and Back, another output of the current-limiting resistor 3 is connected to the combined first terminals of the closing contacts 33 and 34 of the Forward and Nahad contactors, the other drives of contacts 31 and 34 are combined and intended to be connected to the first phase of the mains supply, the other outputs of the contacts 32 and

33 are connected and intended to be connected to the second phase of the supply network, another output of the current limiting resistor 4 is connected to the combined first terminals of the make contacts 35 and 36 of the Forward and Back contactors, the other terminals 35 and 36 are combined and intended to be connected to the third phase of the supply network, common point of connection of the same terminals of the coils 18 and 19 of the contactors Forward and Back and coils of 12.15 intermediate relays through the disconnecting contact 37 of the thermal relay is connected to one output of the coil 27 of the shunt contactor and clamped to connect to the third phase of the mains, the other terminals of coils 12 and 15 of the intermediate relay are connected to other terminals of the disconnecting contacts 20 and 21 of the Back and Forward contactors and through the disconnecting 1st contacts 10 and 11 of the motor speed control relay connected to other buttons 22 and 23 Start forward and reverse start, the closing contacts 13 and D6 of the intermediate relays are connected in parallel with each other and one common terminal is connected to the common connection point of one terminals of the closing contacts 8 and 9 of the speed control relay trodvigate. other outputs are connected to each other. The terminals of coils 12 and 15 of the intermediate relay, the other terminal of the coil 27 of the shunt contactor, are connected via series-connected closing contacts 14 and 17 of the intermediate relays to the other common terminal of the closed contacts 13 and 16 and intended for connection to the first phase of the mains.

The device works as follows.

When you press the button 22 Start forward through the normally closed contact 20 of the contactor Back, the closed contact 10 of the speed control relay (contacts 8 and 10 of the speed control relay work only when turned back), button 26 and contact 37 of the thermal relay receive power coil .8 contactor Forward, contactor Forward turns on closes its contacts 31.33 and 35, connects electric motor 1 to the three-phase network through current limiting resistors 2.3 and A, closes its contact 24, locks the button 22 and opens its contact 21 in the circuit power coil 19 to ontaktor back. At the same time, the first intermediate relay triggers, which closes its contacts 13 and 14. The electric motor begins to rotate, while contacts 9 and 11 of the motor speed control relay are triggered. Pin 9, closed, energizes the second intermediate relay cartridge 15 via closed contact 13, closes contacts 16 and 17, while contact 16 coil 15 self-locks and contact 17 supplies power to shunt contactor coil 27 through closed contact 14 , the shunt contactor is triggered and with its contacts 28.29 and 30 it shunts current-limiting resistors 2,3 and 4. The motor start is complete.

When the button 26 is pressed, Stop loses power to the coil 18 of the forward contactor and the pilot relay 12 of the intermediate relay, this opens the contacts 31.33 and 35 of the contactor Forward, disconnecting the motor from the network, opens contact 24 shunting the start button 22 and closes contact 21 in the circuit powering the coil 19 of the contactor Back open

pins 13 and 14 of the intermediate relay at the same time loses the power supply of the coil 27 of the shunt contactor and it is turned off, including current limiting resistors 2, 3 and 4 in the stator motor winding circuit. At the same time, the coil 19 of the contactor is fed back through contact 21 through the closed contact 16 of the intermediate relay and The closed contact 9 of the motor speed control relay, the Back contactor, closes its contacts 32, 34 and 36, and the deceleration starts. After the motor stops, the speed control relay opens its contact 9, breaking the power supply circuit of the coil 19 of the contactor Back and the coil 15 of the intermediate relay, and contacts 32.34 and 36 that disconnect the motor from the network, contact 16 and the contact 11 of the speed control relay open this process of braking the motor ends.

When you press the button 23 Start Back, the device works in the same way, but contacts B and 10 of the speed control relay are activated (contacts 9 and 11 only stop when rotating Forward).

Thus, this device provides reliable and accurate braking by switching off a three-phase asynchronous electric motor, thus creating a double break in the power supply circuit of contactors and intermediate relays, which eliminates the possibility of spontaneous engine start when the dvidatel turns the shaft, and also rotates the electric motor in the opposite direction after the end of the braking process.

Claims (1)

Invention Formula A three-phase asynchronous electric motor braking device containing three current-limiting resistors, one of the two of which is connected to two phase terminals of the stator winding through thermal relay loops, the third phase output of which is connected to one output of the third current-limiting resistor, counter-speed electric motor relay with two closing and two opening contacts, two intermediate relays with two closing contacts each, coil which pins are connected by one pins and connected to one pins of the Forward and Back contactor coils, the other pins of which are connected to one pins of the disconnecting contacts of other contactors Back and Forward, the start forward and start back buttons, shunted by the closing contacts of the corresponding contactor, one output of which is combined and through the button The stop is equipped with a clamp for connecting to the first phase of the mains supply, a shunt contactor with three make contacts that shunt the current-limiting resistors, other terminals of each About of them are connected to the combined first terminals of the closing contact of the contactor Forward and the closing contact of the contactor Back, another output of the closing contact of the contactor Forward to the circuits of the first phase of the stator winding and another output of the contact of the contact of the contactor Back to the circuits of the second phase of the stator winding are combined and intended for connection to the first phase of the mains, another output of the closing contact of the contactor Back to the circuit of the first phase of the stator winding and another output of the closing contact of the contactor Forward to the circuit the second phase of the stator winding combined and intended to be connected to the second phase of the mains, the other conclusions of the closure contacts of the contactors Forward O five and Back to the third phase circuits of the stator winding are combined and intended for connection to the third phase of the mains supply, the common point of connection of one terminals of the coils of the Forward and Back contactors and the intermediate relay coils is connected via a break contact of the thermal relay with a single terminal of the shunt contactor and provided with a clip for connection to the third phase of the mains, characterized by intermediate relay coil terminals connected to the other terminals of the corresponding opening contacts of the back and forward contactors and through the opening contacts of the speed control relay are connected to the other outputs of the Start Forward and Start Back buttons, respectively, the first closing contacts of the intermediate relays are connected in parallel with each other and one common output terminal with a common connection point for one terminals of the closure contacts of the speed control relay, the other terminals of which are connected to the other terminals of the coils of the intermediate relay, the other output shunt contactor coil through connected in series. the second short-circuiting contacts of the intermediate relays are connected to another common terminal of the first closing contacts of the intermediate relays to connect to the first phase of the mains supply.