Are there other methods of obtaining variable output speeds?
A – If fixed ratios of synchronous speeds are required, mechanical dual speed motors (Model PA, etc.) offer a broad range of slower speeds. If speed ratios are 2 to 1, electrical pole-changing motors are available in some speeds. Where continuously variable non-synchronous speed is required, an induction or D.C. motor should be considered. Certain applications might be adaptable to the use of stepper motors as well.
