... use, based upon YTSP-series VVVF variab YTSZ-series VVVF variable speed three-phase induction motors for metallurgical and crane use, based ... by frequency converter. Speed can be varied in a wide range, under the condition of open-loop U/f control, maintaining constant ... of frame size 400). And under the condition of vector control, speed range can be even expanded, that is, motor operation with ...