Saturday, December 7, 2013

Windmill pictures, as promised

This is what the current windmill generator looks like, without:
  1. Final wiring
  2. Rotating mount (so it can turn to face into the wind)
  3. Pole - to situate it above the ground

The propeller and wind vane were both recycled from my initial mini wind generator that I built over the summer.  The body is made from aluminum, that I originally purchased to fabricate propeller blades - I think it cost around $8 and I only used half the of it. 

The propeller is screwed onto a nylon spacer which is in turn secured to the stepper motor shaft (which has a collar with spokes) using Loctite Plastic Bonder Epoxy (I first tried using 2 set screws to lock the nylon spacer to the spoke wheel and then tried hot glue - that secured it long enough for the tests I ran to determine generator output at 15 mph wind speed. It came off after that).  The back of the stepper motor and the board on the side of it that connects to its power cable I coated in clear latex to protect them from water - preventing it from shorting out the or water getting in and freezing inside the motor and locking up the generator.

Some notes concerning height and placement of a windmill.   Ideally it should be at least 30 feet off of the ground since that height removes it from the level of gusts and places it in the area of more consistent air flow.  In addition,  it is generally best to place it as far as possible from other structures - 1) In case the windmill falls over, don't want it to damage any buildings, 2)Nearby structures will interfere with airflow - this even applies to rooftop windmills.  This does not mean you can't place them in these areas, only that they will be less efficient.

This mini-windmill will be fairly close to structures and not very high (planning to place it about 10 feet off the ground).  I need it fairly close to the birdbath to minimize resistive losses from the wires carrying the power.  So, this won't be as efficient a generator as it could be but I shouldn't really need much power.