Re: [EE]:: Operation of water pumps from Wind Turbines

DC at some kW has challenges, not least of all safety. DC motor might mean 
brushes, not ideal for longevity. Brushless DC motor gets you back to inverter type 
electronics: cost & complexity. Submersible pumps seem to be (mostly, I think) AC 
induction motors, for simplicity and reliability. So, deviating from the idea of DC for a 
moment, thoughts on AC:

Wind Turbine generates 3-ph AC, directly connected by cable to 3-ph induction 
motor water pump at bottom of well. That part is about as simple as it can be other 
than a fully mechanical drive, and you might argue that mechanical could be less 
reliable. Control system problem is all above ground. Gearbox or other dynamically 
variable connection between WT and generator to provide variable 
frequency/voltage/power to pump. (That sounds too simple, needs cleverness, this 
will be the area that makes or beaks the idea). Instead might have 
rectifier/battery/VFD here if there's a good case for it. Control system inputs are 
water demand and WT speed. Control system outputs are generator gearbox 
control, and WT furl/feather. Short term over-supply of wind energy might be 
partially handled by pumping more water, longer term you might want to not abuse 
the aquifer. Fun~!

Brent

On 31 Mar 2025 at 21:33, RussellMc wrote:

> TL;DR / Summary
> 
> Comments on the following are invited - especially the practicality of
> using DC powered deep well water pumps to allow direct powering of water
> pumps by wind turbines across a wide range of wind speeds.
> Of significant uncertainty is the practicality of powering a 1-5 kW range
> DC powered pump from a highly variable wind source, and the ability to load
> the turbine close to maximally at all times to prevent damage.