Motor speed control system.

摘要

A motor speed control system for electrically operated domestic appliances, for example food mixers, includes, as the prime mover, a D.C. permanent-magnet motor in which the permanent magnet material is a magnetic ceramic, such as barium ferrite. Associated with the motor is a speed control circuit which incorporates components that limit the maximum current supplied to the motor to a level that is not sufficient to demagnetise the ceramic magnet material.