JPS5533832A - Exciting method of synchronous motor for rolling - Google Patents

Abstract

PURPOSE: To enable the synchronous motor to be miniaturized by detecting the material to be rolled with the detector on the upper stream side of the rolling mill before it is bitten into the rolling mill, intensifying the excitation of the field system of the synchronous motor then weakening the excitation of the field system after the trailing end of the material to be rolled goes out of the rolling mill.

CONSTITUTION: When the material 4 to be rolled is conveyed to a rolling mill by conveying rollers 3, the leading end of the material 4 to be rolled is detected with a detector 5. Next, the signal of the detector 5 is sent to a field control unit 7 of a synchronous motor 2 through a timer 6 to intensity the excitation of the field system of the motor 2 and increase the torque of the motor to the magnitude required for rolling. The timer 6 is beforehand so arranged as to permit time adjustment because there are cases when the conveying speeds of the material 4 to be rolled are not constant. Next, the signal when the trailing end of the material 4 to be rolled goes out of the rolling mill 1 is sent to the field control unit 7 through the timer 6 to weaken the excitation of the field system of the motor 2.

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