Low-voltage motor control centers utilizing microprocessor technology

Low-voltage squirrel cage induction motors are used in cement mill conveyors, dust collectors, crushers, mills, separators, and fans. There are many types of starters used to control these motors, including manual, magnetic, solid state, and adjustable frequency. However, most motors in the 10 to 400 hp range use magnetic contactors with thermal overload relays. Recently, a new type of magnetic starter that includes a built-in microprocessor was invented. The author describes the design of this starter and the manner in which this new design is able to solve a variety of problems inherent with conventional magnetic motor starters