High-efficiency single-phase motor

A three-phase induction motor was supplied from a single-phase public utility using a new and unique reconnection of the machine windings and three power capacitors to provide balanced currents and voltages in all of the windings and the corresponding three-phase high efficiency. Zero-crossing solid-state relays changed the capacitor values in response to load changes so that the single-phase efficiency was within 3% of the three-phase efficiency for all shaft loads between 20% and 120%. The single-phase power line power factor was near unity for a wide range of powers. This method is applicable to both high efficiency and standard three-phase motors without motor modifications