ELECTRIC DRIVE CONTROL PROCESS Russian patent published in 1998 - IPC

FIELD: adjustable-speed commercial drives using induction motors. SUBSTANCE: speed setting generator controls frequency setting signal and generates three-phase sets of basic current and basic emf setting signals across speed governor output; threes values are in phase quadrature and their modules depend on respective setting signals; basic emf module setting signal is determined by multiplying basic current module setting signal by frequency setting signal; basic current module setting signal is determined by adding basic current module setting signal at no load to current setting signal increment signal and motor particular-phase emf setting signal; current setting signal is found by adding basic current setting signal for particular phase to respective current setting signal increment signal. EFFECT: enlarged motor speed control range due to increasing tightness of mechanical characteristics. 6 dwg