Author Options:

how to use bike gears to control speed of vertical axis windmill for pumping water? Answered

I would like to use bike gears to switch gears eighter clockwise, or counterclockwise on a vertical axis windmill for pumping water. The purpose is to slow down the speed of the spinging rotor or switch it intoa idler gear, to allow the rotor to keep spinging, and to disconnect the water pump, so it wont' be damaged in high winds; Also not to slam the rotor to a sudden stop, by ingageing a brake. I am building this not only for myself, but also my church for them to give away free to needly people around the world. Thank you for any and all help in this matter.


Derailleurs work in one direction only. If you reverse the direction and try to shift the just jam. That should not be a problem, just set them up so that they are working in the right direction. You could probably connect them to a governor that would change gears so that no matter what the wind speed the gears were set to provide proper pump speed. The adjustment might be tricky though. To disconnect the rotor from the gears might be a different problem. There is not idler position on a bike. So you will have to rig up a clutch system that would disconnect the gearing. Several systems that I have looked at have a governor or force monitor that will turn the blades parallel to the wind so the the rotor quits turning when the wind gets too high. That is a much safer system since during over speed operation in high wind conditions can cause catastrophic failure and parts flying off in every direction. It's better for it to fail by collapse in a high wind. Do you have any plans or drawings of what you are proposing? It's really hard to give any better suggestions when the field is so open.

I'd be inclined to use a governor to drive the derailleur, like one of those automatic gear changing bikes, but instead of pulling the cable as the speed increases, hook the cable to the other side of a cam so it loosens on speedup.The problem, however, is that I think those gizmoes are directly connected within the derailleur, so it would take some creative thought to reversing their operation.