SU418948A1 - DEVICE FOR ELECTRIC MOTOR CONTROL - Google Patents

Description

one

The invention relates to the field of electric drive.

The known devices for controlling the motor with the HELP of the contactor and the Start and Stop with self-reset buttons, which contain an electromagnetic time relay and a diode connected in series with it, do not provide an operative deviation and the ability of the motor to self-start at a short-term deep voltage drop.

The proposed device is free from the indicated drawbacks due to the fact that it is equipped with an additional diode, connected by a cathode to a common point of a time relay and a nepiBoro diode, and the anode through an opening contactor contact to the control circuit of the power source, moreover, between the first diode and the other wire of the control circuit of the contactor a closing contactor contact is inserted.

The drawing shows a schematic diagram of the proposed device.

When the start button, contactor K is pressed, it self-locks (contact / K) and with its closing 2K contact it supplies power to the time relay coil RV, which flows around the rectified current: m along the following circuit: network - button Stop, relay coil RV, diode Dy closing block

contact 2K contactor - network. The relay is also activated by its closing contact / PB shunting the “Start. When the button is pressed, the Stop contactor disappears, and at the 5th beginning the closing 2K contact closure opens, and then the opening block closes the AC contact. As a result, a change in the direction of the current in the relay coil occurs. In this case, the relay coil flows around 0 rectified current through the following circuit: network - block - contact LC, diode D2, coil PB relay, closing contact / PB relay, coil K. contactor - network.

5 Due to the forced demagnetization of the relay, the latter disappears without a time delay, simultaneously depriving the power supply (contact / PB). Since when the button is pressed, the stop relay gives almost no time delay, the normal operation of the button stop is ensured.

It should be noted that in the process of forced demagnetization of the relay, the coil of the contactor coil flows around the current.

However, the contactor does not work, since in this circuit there is much less current to trip the contactor (the resistance of the relay coil is much greater than the resistance of the coil of the contactor).

With the disappearance or deep decrease of the mains voltage, the contactor disappears and simultaneously loses power to the time relay. If the voltage is reset before the relay expires, a self-start will occur. Thus, the proposed device provides both self-starting and normal functioning of the “Stop.

Subject invention

A device for controlling an electric motor with a POMOYAI contactor and buttons "Start and" Stop with self-return, containing an electromagnetic time relay and sequentially

a diode connected with it, characterized in that, in order to accelerate the operational disconnection with the possibility of providing the motor self-start during a short-term deep voltage drop, it is equipped with an additional diode connected to the common point of the time and first diode cathode and the anode through the disconnecting - contact of the contactor to the wire of the contactor control circuit up to the Stop button on the power supply side, with a closing block between the first diode and another wire of the contactor control circuit; Torah.