SU143889A1 - Device to control a two-phase AC motor - Google Patents

Description

Devices are known for controlling two-phase AC motors with power supply to the windings through semiconductor voltage converters made in a bridge circuit.

The proposed device of a similar purpose differs from the known ones in that two magnetic multivibrators with forced starting through phase-shifting magnetic amplifiers, the bias windings of which are connected counter to the common source of the control signal, are used to control and reverse the voltage on the control winding.

To increase the sensitivity of the device near zero voltage on the motor control winding, the output windings of one multivibrator are connected to the input of one pair of bridge transistors connected between the plus and minus of the power supply, and the output windings of the other multivibrator to the input of another pair of bridge transistors.

A schematic diagram of the described device is shown in the drawing.

The device consists of an unregulated bridge A with transistors, supplying a coil / excitation, and a controlled bridge B with transistors, supplying a control motor winding 2 3. The transistors of an uncontrolled bridge are powered from the secondary windings 4 of the master magnetic multivibrator B. The transistors of the controlled bridge B feed from magnetic multivibrators G and D with forced start from the master multivibrator through phase-shifting magnetic amplifiers 5 and, the windings 7 of biasing which are included opposite to the common source IR control signal. With one polarity of the control signal, the saturation of the cores of one magnetic amplifier decreases and the second increases, which

No. 1438892 leads to a corresponding decrease and increase in the phase shift of the multivibrators G and D with respect to the output voltage of the multivibrator B. As a result, a certain duration n of the phase of the control pulses and the voltage across the load is established. When reversing the polarity of the control signal, the direction of the phase shift of the output voltages of the multivibrators changes, therefore the phase of the control pulses and the voltage on the load (on the control winding) are reversed. To increase the sensitivity of the device near zero when reversing the voltage on the winding, control one pair of bridge transistors connected in series between the plus and minus of the power source, supply the output voltage (winding 5) of the multivibrator G, and the other pair - the output voltage (winding 9) of the multivibrator E. Increasing the sensitivity of the device is caused by this inclusion by shorting for a pause time of a control winding with significant inductance.

These positive features of the described device determine its usefulness and applicability in various industrial systems.

Subject invention

Claims (2)

1. A device for controlling a two-phase AC motor powered by windings through semiconductor converters made according to a bridge circuit, characterized in that, in order to regulate and reverse the voltage on the control winding, two magnetic multivibrators are used with forced start through phase-shifting magnetic amplifiers, windings the magnetizations of which are turned on counter to the common source of the control signal. 2. The device according to claim 1, characterized in that, in order to increase the sensitivity of the device near zero voltage on the motor control winding, the output windings of one multivibrator are connected to the input of one pair of bridge transistors connected between the positive and negative power source, and output windings of another multivibrator - - to the input of another pair of bridge transistors.  R ,, T T7pc: 3-J , o-av-vw-o , o-LL / U-LALg-o -VW-WV-0- LLLGLLLLg-in