METHOD FOR METERING ACTUAL SPEED OF MULTIPHASE INDUCTION MOTOR Russian patent published in 1997 - IPC

FIELD: speed and torque governing for multiphase induction motors. SUBSTANCE: method involves stepped variation of multiphase induction motor speed by varying stator current frequency to value corresponding to desired speed pre-calculated for each speed step. Stator current is measured and its RMS value is compared with pre-calculated desired speed for each step. Variation of stator current frequency is ceased according to comparison results and is maintained constant until RMS value of current decreases below specified value. Mentioned operations are repeated until current frequency is brought in correspondence with desired speed. Frequency is varied in direction opposite to motor speed variation. EFFECT: provision for largest possible useful speed range of motor in transients. 3 cl, 1 dwg