CIRCUITO DI PROTEZIONE DA ARRESTO PER MOTORE COMMUTATO ELETTRONICAMENTE

A control circuit for a system including an electronically commutated motor. A tachometer pulse signal generator generates a signal representative of the rotational speed of the rotatable assembly of the motor and having a duty cycle. The control circuit comprises first and second motor voltage inhibiting circuits. The first inhibiting circuit inhibits application of the motor voltage to the winding stages of the motor in response to the tachometer pulse signal when the motor speed is below the preset minimum speed. The second inhibiting circuit inhibits application of the motor voltage to the winding stages in response to the tachometer pulse signal when the duty cycle of the tachometer pulse signal is outside a preselected acceptable range. Application of the motor voltage to the winding stages is inhibited when the motor is stalling as indicated by the motor speed being below the preset minimum speed or as indicated by the duty cycle of the tachometer pulse signal being outside the preselected acceptable range.