spring return butterfly valve actuator, spring control method and butterfly valve assembly

摘要

spring return butterfly valve actuator (1) including: a multi-coil electric dc motor (c1, c2, c3) (2) having an output shaft, a butterfly valve return spring (10), a transmission gear unit (5) connected to the output shaft, a control unit (cpu) adapted to control the power supply to the dc motor (2), wherein the spring return butterfly valve actuator (1) has a range between closed butterfly valve and open butterfly valve. the control unit (cpu) is arranged to short-circuit at least two dc motor coils (c1, c2, c3) to create a dc motor return resistance torque and the control unit (cpu) includes a motion monitoring circuit arranged to monitor actuator movement forced by the butterfly valve return spring (10) and resisted by the dc motor return resistance torque. The invention also relates to a method and a butterfly valve assembly.