Here are two views of the 4 inch butterfly valve and modified (a little) car window operator that modulates the valve to keep the voltage steady as power demand varies.Frustration overcame when I tried to upload PDF files to my blog, so here is a link to the PDF diagram for the valve controller. The butterfly valve is driven by a car electric window operator becaus
e of its high torque and harsh environment operating capability. The controller was built to operate 2 valves and has battery backup for manual control, when all else fails.http://www.scribd.com/doc/3198857/Valve-Voltage-Frequency-Control-Circuit
Download http://www.scribd.com/doc/3198677/3-phase-motor-as-1-phase-generator-diagram.pdf
