Speed control for industrial sewing machine - uses constant speed electric motor with controlled electromagnet biassing drive wheel against friction pads on motor flywheel

摘要

The system is for speed control and positioning of variable speed machines driven by electric motors. Including constant speed electric motor (1) driving a flywheel (2) fitted with friction. The variable speed machine has a drive shaft. This drive shaft (4) is coaxial to the shaft of the flywheel. The system includes a rotational speed detector for the driven machine and position detector for a part of the machine. The drive shaft supports a metallic disc (17) which is pulled by a spring (18) towards the friction pads (7). These friction pads (7) are fixed on the base of the control system. An electromagnet (9) attracts the metallic disc (17) towards the friction pads (3) on the flywheel (2). The control supplies variable voltage to the electromagnet which attracts the metallic disc (17) to control the speed of the driven shaft.