A Novel Use of the Silicon Controlled Rectifier to Run Multiphase Induction Motors from a Single-Phase Supply

The supply of electrical power to small, remote situations is usually carried out by means of a two-wire, single-phase connection. Frequently, this remote situation is developed and the electrical power consumption increases significantly. Not only is there an increased overall demand on this service, but the provision of three-phase supplies to run electric motors also becomes highly desirable. The considerable expense of laying extra lines to carry the three phases could be avoided if a single to three-phase conversion system were readily available. This paper describes such a conversion system using silicon controlled rectifiers in straightforward switching roles. Test results on laboratory induction motors indicate that there is little difference in performance when fed from this system and when fed from the appropriate sinusoidal supplies. Data for the construction of a harmonic filter are included for applications when the raw, switched voltage waveform may be unacceptable.