Method for detecting position of rotor of electric motor e.g. brushless direct current motor, involves providing electrical isolation unit to temporarily, partially and electrically insulate motor phase from common point

摘要

The method involves using counter electromagnetic force voltage partially at motor phase of electric motor (5) by scanning the counter-electromagnetic force voltages. A crossing of particular voltage level of counter-electrode magnetic force voltage is detected in which phases of electric motor are connected to each other by common point. An electrical isolation unit is provided to temporarily, partially and electrically insulate the phase from common point. An independent claim is included for electric circuit device.