Variable 3-phase reversible voltage sources with use of saturable reactors

This paper describes the circuit arrangements, with appropriate analyses, by which two or three saturable reactors may be used to supply a 3-phase load. The output voltages of the devices are constant-frequency 3-phase, almost sinusoidal sources which may be smoothly and continuously varied from an almost balanced positive sequence to an almost balanced negative sequence by variation of the saturable-reactor control currents.