| 摘要 |
PURPOSE:To perform easy maintenance for a sewing machine by employing a low inertia AC induction motor as a drive motor and driving the motor via a variable voltage and variable frequency inverter, thereby improving the controllability and eliminating an electromagnetic clutch. CONSTITUTION:A motor 14 for driving sewing machine 10 employs an AC induction motor which has a rotor 40 of low inertia in cup shape opposed to a stator 38, and is driven by a speed control circuit 32 which has a variable voltage and variable frequency inverter 100. A signal is outputted from a detector 30 by depressing a foot pedal 28, thereby controlling the inverter 100, a signal of a needle position detector 24 provided at the machine 10 is inputted to a sewing machine controller 34, thereby controlling the inverter 100 and an electromagnetic brake 18 to stop the needle at the prescribed position. Accordingly, the electromagnetic clutch can be eliminated, thereby simplifying the maintenance and improving the controllability in the variable speed. |
