ELECTRICAL DRIVE SYSTEM FOR A SEWING MACHINE

摘要

An improved speed controlling system for an electric sewing machine motor. The system includes a motor connected to a power supply, one or more speed controlling circuits for operating the motor at variably controlled speeds, and one or more electrical braking circuits for braking the motor upon receiving a deceleration command from the speed controlling circuit to slow the motor from high speed to low speed. Electromechanical brakes brake the motor, during at least a part of the braking period, the braking means being controlled by the electrical braking circuits. A low speed setting circuit is provided in the speed controlling circuit for maintaining low running speed caused by the electromechanical braking means and the electrical braking circuits. A circuit is provided for stopping the motor, after the motor has been slowed to a low running speed by the low speed circuit, by the electrical braking circuits on command from the electromechanical brake.