GENERAL-PURPOSE ELECTRIC DRIVE FOR SEWING MACHINES Russian patent published in 1997 - IPC

FIELD: sewing equipment. SUBSTANCE: electric drive has three-phase short-circuited asynchronous electric engine connected with sewing machine 1 through belt drive 2 and controlled by microprocessor 6 through inverter 4, whose input is switched to rectifier 5 and microprocessor 6 and output is connected with winding of stator 7 of engine 3. Input of microprocessor 6 is connected to pedal-actuated controller 8 and to sewing speed decrease signal correction unit through belt drive 9. Microprocessor has memory unit 10, sewing parameter setting panel 11, sewing speed detector 12, sewing machine main shaft 13, driven pulley 14 of belt drive 2 and sewing needle 15. Transmission ratio of belt drive is equal to ratio of maximum sewing speed and nominal speed of electric engine. Dimensions, weight, electric and magnetic parameters of electric engine are adapted for commutation current of increased frequency of 60-450 Hz. Microprocessor varies electric engine speed from nominal to lower value. Electric engine used is of multipolar type. EFFECT: increased efficiency, wider operational capabilities and enhanced reliability in operation. 5 cl, 3 dwg, 1 tbl