Patent ID: 7230400

Claim:
An electronically commutated motor comprising: a stator, a rotor, and a program-controlled microprocessor, serving to control commutation of the motor; said rotor rotating, during motor operation, through a plurality of commutation angular ranges, during each of which a commutation takes place as the rotor rotates therethrough, each commutation being preceded by: a) rotation of the rotor through a measuring angular range having a predefined angular relationship with a subsequent associated commutation angular range during which said commutation is to occur, during which measuring angular range data, relating to a time duration variable (t_H) needed by the rotor to rotate through said range, are ascertained; b) rotation of the rotor through a calculation range, during which a first time interval (t_TI) is calculated, based upon said time duration variable (t_H); c) a time measuring step, during which a time corresponding to said first time interval (t_TI) is measured, beginning at a predefined angular orientation of the rotor associated with said associated commutation angular range; and d) an interrupt routine, triggered upon conclusion of said time measuring step, said interrupt routine being operative to control, during said associated commutation angular range, time-advanced commutation, when said motor is operating in a steady state.