GB549536A - Improvements in and connected with induction regulators and their application - Google Patents

Abstract

549,536. Induction regulators; A.C. commutator motor control. SCHWARZ, B. May 26, 1941, Nos. 6750/41, 2960/42 and 3168/42. [Classes 35 and 38 (ii)] A single induction regulator has its primary winding P connected in series with its secondary winding S, the arrangement being such that the output voltage (taken, for example, from the connecting parts between the windings) may be resolved into a component of constant voltage and a component of variable voltage preferably of fixed phase position. In the vector diagram, Fig. 1a, 01 represents the supply voltage which is the vectorial sum of the voltages of the windings S and P represented respectively by 02 and 21 or 021 and 211 &c. according to the adjustment of the regulator. If the coils P and S are equal, the points 2, 21, 211 &c. will lie on a straight line and the output voltage will be represented by O2<SP>1</SP> &c. which may be resolved into the constant voltage 02 and the variable voltage 2, 21. If desired the constant voltage component can be varied or eliminated by applying a suitable voltage in series with the windings S, P (Figs. 2, 5, &c., not shown). If the coils P and S are not equal, the. points 2, 21 &c. will lie on a circle. The regulator is specially adapted for controlling a stator-fed A.C. commutator motor, the constant voltage component providing a magnetizing current in the commutator circuit for power factor compensation, and the variable voltage component serving to regulate the speed. Fig. 3 shows a simple arrangement, one only of the three phases being represented, and IR representing the induction regulator which is supplied from a transformer St, F, the primary of which viz. St, is the stator winding of the motor C. In modifications the regulator is fed directly from the supply and the output passes to the motor via a transformer. In another arrangement, Fig. 10, each winding P and S of the regulator has a secondary winding PS and SS and the secondary windings are connected in series with the motor. In modifications of this last form, Figs. 1a, 2a, 3a of the second Provisional Specification, (not shown), the stator circuit may also be varied to provide increasing or decreasing torque with varying speed. Fig. 1 (3168/42) shows an arrangement including a switch RS for reversing the motor. A primary winding PT connected directly to the line supplies the induction regulator IR by means of the secondary F and the reversing switch RS connects the motor to one or other of two tappings on this winding F. The result is that the voltage from the regulator has an extra voltage added to it and the resulting constant voltage component for the motor is positive or negative according to the particular tapping.