SU56180A1 - AC motor control method - Google Patents

Description

The most flexible way to control a variable-current motor is by means of ion devices. However, in its usual form, it requires the use of ion devices, usually for dual engine power (taking into account the reverse), which is a significant drawback.

The proposed method of controlling an AC motor makes it possible to bypass ion devices (in some cases, electron tubes) with minimal power and apply it to any AC motors. According to the proposed method, in order to change the phase order at the motor terminals and regulate the applied voltage, the controlled motor is fed through a group three-phase transformer with bias, in which the windings are connected in an open triangle so that when it is magnetized (using controlled straighteners ) one or the other part of the magnetic circuit of the transformer received a different order of

phases. In the particular case, for controlling a single-phase collector motor, instead of a group transformer, chokes with a bias can be used.

The invention is illustrated in a schematic drawing, FIG. I, 2 and 3 of which depict electrical control circuits for the proposed method, and FIG. 4 transformer structures with bias.

The diagrams of FIG. 1 (for a short-circuit engine) and in FIG. 3 (for a shunt collector motor) contain a motor 6, powered by a three-phase network R, S, T through transformers 1, 2, 3 with biasing. Transformers 2, 3 (Fig. 4) are connected in such a way that, in the absence of a magnetizing current, they give zero voltage and gradually increase the voltage as the bias increases.

The secondary windings of the transformers /, 2, 3 are included by an open triangle, and when voltage is applied by transformers /, 5, the direction of rotation of the field back to