SU1365318A1 - Device for starting 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 simplify by reducing the number of wires to the control buttons. The motor Forward is started by opening button 4 and closing contact 9. In this case, one half-period rectified current through the circuit: button 1 - button 5 - contact 9 - diode 16 passes through the winding of the contactor coil 10 and turns it on. In order to disable this mode of operation, a short-time action on the Stop 1 button or simultaneous action on the control buttons 4 and 5 results in breaking the power supply circuit and the device returns to its initial state. The electric motor is started back in a similar way to the symmetrical control circuit. .1 il. i (L

Description

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

The aim of the invention is to simplify by reducing the number of wires to the control buttons,

The drawing shows the scheme of the proposed device for starting an asynchronous motor.

A device for starting an asynchronous motor contains a button 1 Stop one pin 2 of which is equipped with a clip for connecting to a power source, another pin 3 of button 1 Stop is connected to one pin of the disconnecting contacts of button 4 of the Forward control and buttons 5 of the Naz control, respectively, the second pin 6 is open - the pin of the button 4 Forward is connected to one output of the closing contact 7 of the button 5 Back the second input 8 of the opening contact of the button 5 Back is connected to one output of the closing contact 9 of the button 4 Forward, coils 10 and 11 of the contact Forward and Backward with closing contacts 12 and 13, one terminals of coils 10 and 11 are combined and provided with a terminal for connection to a power source, shorting contacts 7 of control buttons 4 and 5 are bridged by capacitors 14 and 15, other terminals of closing contacts 7 and 9 buttons 4 and 5 of the control are connected to the anodes of the diodes 16 and 17, respectively, whose cathodes are connected to the other terminals of the coils 10 and 11 of the Forward and Backward contactors, the diodes are shunted by the closing contacts 12 and 13 of the Coils of the 10 and 11 forward and backward contactors.

The device works as follows.

In the initial state, when the AC supply voltage is applied, the device is in the disconnected state, the coils 10 and 11 of the contactors are de-energized, since diodes 16 and 17 and capacitors 14 and 15, respectively, are connected with them. When acting on the control buttons (for example, 4, switching on the operating mode Forward), button 4 is opened and contact 9 is closed, while the half-wave rectified current in the circuit: button 1 - button 5 - contact 9 - diode 16 passes through the winding

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ke coil 10 contactor and turns it on.

Simultaneously with the power contacts of this contactor, including the operation mode of the electric motor Forward, contact 12, shunt diode 16 is closed. At the same time, the contactor receives a full sinusoidal supply voltage, and when the control button returns to its original position, it is reliably held in the on state by a sinusoidal current through the capacitor 14 To turn off this mode of operation, sufficiently briefly acting on button 1 Stop or simultaneously acting on button Lee 5 of the control, thereby breaking the power supply circuit and the device returns to the initial state.

Switching on the operating mode of the electric motor Back is similar, i.e. when the control button 5 is applied, button 5 is first opened, and then contacts 7 are closed, while the first phase into the conducting half-period of the power supply voltage, circuit: button 1 - button 4 - contacts 7 and 6 - diode 17, comes to first the output winding of the coil 11 of the contactor and includes it. Simultaneously with the power contacts of the contactor, including the operating mode of the electric motor, the back of the contact 13 is closed, the shunt diode 17, the contactor receives the full sinusoidal voltage of the power source, and when the control button returns to its original position, it is reliably held in the on state by a sinusoidal current through the capacitor 15 .

This mode of operation is disabled in the same way as the previous one by briefly opening the Stop 1 button or by simultaneously operating the Control buttons 4 and 5.

Transition from one mode of operation of an electric motor (for example, Forward) to another (Back) and vice versa can be carried out, without affecting the Stop button 1. To do this, simply turn on the corresponding control button.

Claims (1)

Invention Formula A device for starting an asynchronous motor, containing a stop button, 313653 one output of which is provided with a clip for connecting to a power source, another output of the Stop button is connected to one of the opening contacts of the Forward and Back control buttons, respectively, the second output of the Forward button's opening contact is connected to one output of the closing contact of the Back button, Q second output of the opening contact of the Back button connected to one output of the closing contact of the Forward button, the coils of the contactors Forward .. Red and Back with the closing contacts of 15 tons, one terminals of which are combined, are provided with a clip for connecting 184 to the power source, characterized in that, in order to simplify by reducing the number of wires to the control panel, two capacitors, two diodes closing the contacts of the control buttons Forward and Back are bridged by capacitors, the terminals of the closing contacts of the control buttons Forward and Back are connected with diodes anodes, respectively, whose cathodes are connected to other terminals of the Forward and Backward contactor coils, the diodes are shunted by the make contacts of the Forward and Backward contactors coils.