TORSIONAL OSCILLATIONS ASSOCIATED WITH THE STARTING OF 3-PHASE SYNCHRONOUS MOTORS FROM A SINGLE-PHASE SUPPLY

Recent studies have proved that the operation of three phase synchrono us motors from a single phase supply is possible. This adds more flexi bility to the operation of these motors and extends their field. Howev er, previous work carried out neglected the effect of the torsional dy namics of the motor-load-shaft assembly, that exist particularly with motors driving a reciprocating type multi-compressor loads. Such an ef fect may have damaging consequences when one or more of the natural fr equencies of the mechanical system coincides with one or more of the n atural frequencies of the electromagnetic torque components. This phen omenon is called electro- mechanical resonance. The main objective of this paper is to take the effect of this phenomenon into consideration through the development of a rigorous mathematical model coupled with a sound digital simulation.