CS222741B1 - Connection of compensation circuit with mercury potentiometer for DC motor control - Google Patents

Abstract

The subject of the invention is an electric circuit using a low-ohm mercury potentiometer in conjunction with an operational amplifier and a circuit for 1-phase control of a triac, for controlling the excitation current of a direct-current electric motor. This single type of circuit can replace all types of high-power multi-watt wire potentiometers used to ensure the synchronous operation of a large number of drive motors included in a work line (e.g. textile and paper).

Description

The present invention is an electrical circuit utilizing the mercury low ohmic potentiometer in conjunction with an operational amplifier and obviodem ^{* 1} for the phase control of a triac control pro- excitation current of DC electric motor. A single type of circuit can replace all types of multi-watt power potentiometers that are used to ensure synchronous operation of a plurality of propulsion motors downstream (e.g., textile and paper).

The invention relates to the connection of a compensating charge with a mercury potentiometer for controlling DC motors.

Until now, compensating devices use a wire resistive potentiometer of various values as an actuator, which serves, for example, to control the excitation of DC motors. The disadvantage of this solution is the low lifetime of these potentiometers, and furthermore, for a wider use for any type of DC motor, a large slortimetry of the values of these potentiometers.

These drawbacks are eliminated by the connection of the compensation circuit according to the invention, which is based on the fact that the control capacitor, the mercury potentiometer and the operational amplifier are connected in parallel to the filter capacitor, while the mercury potentiometer is connected to the inverting input of the operational amplifier. the control potentiometer is connected to the non-inverting input of the operational amplifier, where the inverting input of the operational amplifier is connected. to a phase control circuit input which is connected by its first control output to one triac main electrode and its second control output via a coupler to the triac control electrode, which by its second main electrode is connected to a second power terminal, the first power terminal being connected on the first triac main electrode through the alternating terminals of the diode bridge rectifier whose DC output is connected to the first and second DC output terminals.

The compensation circuit according to the invention comprises an operational amplifier in an integrated design with two adjusting elements, a triac control circuit, a triek and a diiodior rectifier. The adjusting elements allow the circuit to be adapted to any DC motor and also adapted to different operating conditions.

Content Compensation Circuit Connection

Claims (1)

Subject Connection of compensation circuit with mercury potentiometer for regulation of DC motors characterized in that parallel to filter capacitor (12) is connected both regulating potentiometer (2), mercury potentiometer ¹ (1), on the one hand toperation amplifier (3) and on the other (4) ,. wherein the mercury potentiometer slider (1) is connected to the inverting input of the operational amplifier (3), the slider of the regulating potentiometer (2J is connected to the non-inverting input of the operational amplifier (3j) whose inverting input is connected via a variable resistor (7j) the mercury potentiometer is shown in the attached drawing. In parallel to the filter capacitor 12 the control potentiometer 2, the mercury potentiometer 1, the operational amplifier 3, and the prl phase control circuit 4 are connected. The mercury potentiometer slider 1 is connected to the inverting input of the operational amplifier 3. The inverting input of the operational amplifier 3 is connected via a variable resistor 7 to its output, which is further connected to the input of the phase control circuit 4, which is connected by its first control output to the first main electrode of the triac 5 and its second control output through the coupler. to a triac control electrode 5, a serial circuit consisting of a triac 5 and an AC input terminal of a diode bridge rectifier 6, the DC output of which is connected to the first and second DCs, between the first and second power terminals 10, 11; an output terminal 8, 9th The control potentiometer 2 serves for setting the initial control range, while the variable resistor 7 allows to adjust the overall mode of control of the compensation circuit according to the DC motor used. The operational amplifier 3 controls the prl phase control circuit 4, the supply voltage for the operational amplifier 3 being drawn from the phase control circuit 4. For example, the coupler 13 may be resistive, capacitance, or a parallel or series-parallel combination of resistors and capacitances. A DC supply voltage is drawn from the DC output terminals 8, 9 to drive the DC motor. The supply voltage of the operational amplifier 3 is either constant, when using capacitance as coupler 13, or when using resistor as coupler 13, the supply voltage has a pulsating character. OF THE INVENTION which is further connected to the input of the phase control circuit (4), which is connected by a gray first control output to one triac main electrode (5) and its second control output via a coupler (13) to the triac control electrode (5), its second main electrode is connected to the second power terminal (11), the first power terminal (10) is connected to the first triac main electrode (5J) through the alternating terminals of the diode bridge rectifier (6) whose DC output is connected to the first and second DC output terminal (8, 9).