Electronically commutated motor

摘要

An electronically commutated motor has its functions controlled by a microprocessor (50). Outside the microprocessor is a watchdog timing circuit which receives its reset pulse from a rotor position sensor(60) or a further sensor on the motor (20) in order to prevent an activation of this timing circuit above a certain motor speed. The timing circuit has a multivibrator with a low oscillation frequency which, when the motor is running, is held in the deactivated state by the speed signals above a given speed. In the active state, the multivibrator periodically charges up a condenser (96) belonging to a power-up-reset circuit of the microprocessor and which is connected to its RESET input.