Drain valve actuators and methods of controlling drain valves
A valve actuator operates a valve, such as a drain valve of an industrial washing machine. The valve actuator has a permanent magnet DC motor which drives a gear train which rotatably drives an output shaft. The output shaft is engaged with the drain valve and moves the drain valve to open and closed positions as desired. The valve actuator also has a controller which controls operation of the valve actuator. The controller provides power to the motor only when needed to open and close the drain valve. The controller does not provide power to the motor when the drain valve is in the open and closed positions.
1. A valve actuator comprising:
a housing;
an electric motor mounted to the housing and having a motor shaft;
a rotatable output shaft extending through a wall of the housing;
a gear train within the housing and operatively connected to the motor shaft and to the output shaft; and
a controller for providing selective electrical operational power to the motor only when needed, the controller comprising:
an output signal which drives the motor which drives the gear train which rotates the output shaft from a first position to a second position,
a reverse output signal having a reverse polarity which reversely drives the motor which reversely drives the gear train which reversely rotates the output shaft from the second position to the first position,
positive temperature coefficient thermostat which reduces without stopping the output signal to the motor when the output shaft is in the second position.
2. The valve actuator according to claim 1 , wherein the positive temperature coefficient thermostat reduces a current of the output signal.
3. The valve actuator according to claim 1 , wherein the controller further comprises a printed circuit board mounted to the motor.
4. The valve actuator according to claim 1 , wherein the gear train comprises:
a worm mounted on the motor shaft;
a first cluster gear having first teeth engaged with the worm, and having second teeth;
a second cluster gear having first teeth engaged with the first teeth of the first cluster gear, and having second teeth; and
an output gear engaged with the second teeth of the second cluster gear, the output gear engaged with the output shaft such that rotation of the output gear rotates the output shaft.