SU798691A1 - Apparatus for controlling induction electric motor - Google Patents

Description

one

The invention relates to automation and is intended for use in control devices.

Devices are known for controlling asynchronous electric motors Til.

The closest in technical essence is the device, containing control buttons, position sensors, thermal relay, RC circuit, the first terminal of which is connected to the first terminal of the control winding with an synchronous electric motor and anode

VOGO SIMISTOR, second conclusion - from WTO

ring output winding control asin. x; a circular electric motor and an anode of an expensive triac; the third output of the control winding of the asynchronous electric motor is connected through the heating of the heating relay to the first output of the alternating voltage source, the second output of which is connected to the cathodes of the first and second simulators G2,

 The disadvantage of this device is the limited scope.

The purpose of the invention is to expand the scope.

This goal is achieved by c. A resistor, thyristors and a constant voltage source are inputted to the known device, the first output of which is connected via serially connected first control button and the thermal relay opening contacts to the second output of the alternating voltage source, and the second output to the first output of the resistor, the second output of which through contacts

0 of the second control button is connected to the control electrode of the first thyristor and the closing contacts of the first position sensor, successively connected disconnection of the contacts of the second position sensor and disconnecting contacts of the third control button - with the anode of the first thyristor, through the third contacts of the third control button - with the control

0 by the electrode of the second thyristor and by the closing contacts of the second position sensor, through the series-connected disconnecting contacts of the first position sensor and opening

5, the contacts of the second control button, with the anode of the second thyristor, and the cathodes of the first and second thyristors are connected respectively to the control electrodes of the first and second simulators.

The drawing shows a circuit diagram of the device.

The circuit contains an asynchronous motor 1, an RC chain 2, the first and second triacs 3 and 4, the first and second thyristors 5 and b, the source 7 of constant voltage, the winding of the thermal relay 8, the break contact

thermal relay 9, resistor 10, first and second position sensors 11 and 12, first, second and third control buttons 13, 14 and 15, alternating voltage source 16.

The device works as follows.

When you close one of the control buttons, for example, the second button 14, the first thyristor 5 is unlocked and held in an open state by flowing a current of the DC voltage source 7 through the resistor 10, the opening contacts of the second sensor 12, the opening contacts of the third button 15, The first thyristor 5 and the control electrode-cathode junction of the first triac 3. When this opens, the first triac 3 opens and the actuator moves (as specified not shown) under the action of the asynchronous motor 1. When the actuator reaches the second position sensor 12, its contacts switch. When the anode circuit of the first thyristor 5 and the control circuit of the first triac 3 is broken, the first thyristor 5 and triac 3 are disconnected. The control electrode of the second thyristor b is connected through the closing contacts of the second sensor 12 of the position, under the action of which the second thyristor b and the triac 4 are turned on. The asynchronous motor 1 and the actuator driven by it are reversed. Although the contacts of the second sensor 12 are reversed when the actuator is reversed to their original position, the second thyristor 6 is held in the on position by a constant current flowing through its anode circuit. When the actuator reaches the position of the first sensor 11, its contacts are switched off, turning off the second thyristor 6 and triac 4 and turning on the first thyristor 5 and simisFrr 3. In the future, the operation of the device is repeated.

The device is stopped by the third control button 15. In this case, the anode circuit of any of the included thyristors 5 or 6 is broken, and they and the simisto sludge 3 or 4 are closed. The closing and opening contacts of the control buttons 14 and 15 are mechanically interlocked. Therefore, the more the switching current enters the control electrode of any of the thyristors 5 or b, the anode circuit of the previously turned on thyristor is broken. ra. This eliminates the simultaneous switching on of two triacs 3–4. The protection of the induction motor 1 of the device against overload is easily accomplished by the thermal relay 8, contacts 9 which are connected in series with a constant source

 voltage 7 and the first control button laziness 13 ..

The invention is characterized by high sensitivity and reliability of operation, it allows to use position sensors on reed switches in it without any intermediate electromagnetic relays, to protect the motor against overload and zero protection of the entire device. All this will provide him with wide practical application in various systems of automatic control and regulation of technological processes.

Claims (2)

Invention Formula A device for controlling an asynchronous electric motor, comprising control buttons, a position sensor, Q thermal relay, JS-chain, the first output of which is connected to the first output of the control winding of the asynchronous motor and the anode of the first triac, the second output - to the second . the control winding of the induction motor and the anode of the second triac, the third control winding of the induction motor is connected through the winding of the thermal relay to the first output of the source 0 alternating voltage, the second output of which is connected to the cathodes of the first and second triacs, which is so that, in order to expand the field of application of the device, it contains a resistor, thyristors and a constant voltage source, the zero output of which is connected via the first control buttons connected in series and disconnecting l contacts of the thermal relay to the second output of the alternating voltage source, and the second output to the first output of the resistor, the second output of which is connected to the control electrode of the first thyristor and the closing contacts of the first position sensor through the contact point of the second position sensor the position sensor and the opening contacts of the third ynpasheny button — with the anode of the first thyristor; through the closing contacts of the third control button — with the control electrode ohm second thyristor and the closing contacts of the second sensor position through sequentially co. The common disconnecting contacts of the first position sensor and the disconnect switch are the contacts of the second control button with the anode of the second thyristor, and the cathode; the first and second thyristors are connected respectively to the control electrodes of the first and second simulators. Sources of information taken into account in the examination1.; USSR author's certificate 590700, cl. (505 D-3/00, 15у10.76. 2. Thyristors. Technical Reference Nick. Translated from English, ed. Energy V.A. Labuntsova et al. M., 1971, p. 265-266 (prototype).