Saturday, December 14, 2013

Project Bird Bath Heater - Windmill Mount Re-Design

Due to the results of my initial test I needed to redesign and build a better mount for my little windmill, one  that allows rotation but is strong enough to stay attached to the pole it is secured to.

I'm hoping that a better idea is to use an actual bearing assembly instead of a caster wheel from an old rolling shelf (at least I think that's what I salvaged it from). My local Ace Hardware carries flanged axial bearings that should be ideal for this. My only issues are: 1.) how to mount the bearing and 2.) how to secure the axle that I need to place inside the bearing (ideally the axle should be hollow so I can run the wiring through it and down the inside of the pole). Well, I guess I also 3.) need to secure the the whole assembly to the pole – so 3 issues to take care of.
Flanged Axial Bearing

Looking up pictures of mounts for flanged axial bearings I mainly came up with cast iron fittings. Not real helpful but then I saw a picture of a bearing used with a spring type shock absorber and it gave me an idea -  If I could drill or bore out a hole in acrylic, or some other material, just big enough to fit the body of the bearing with the lip (or flange) on the edge of the hole – then I could secure it with set screws or glue. I decided to prototype using wood and if it works out I could try acrylic or some type of hardwood.

I had some scrap 1”x3” poplar board so I decided to use that. Below is what I came up with. Initially I was going to use just 2 layers – 1 for the bearing and 1 for the conduit. But, thought about it and decided to use 2 layers for the conduit connection (providing about 1 ½” overlap of the conduit pipe. Initially, I am just screwing these layers together with galvanized deck screws after sealing the pieces with paint. If this works I'll try and get something better like teak to make the mount out of and round out the corners to make it look nicer. But my first objective is to actually get this functioning.
Wood Layers Drilled out for Bearing and Pole

Stacked Mount

Rt. to Lft.  Locking ring, Bronze Flanged Sleeve Bearing, Flanged Axial Bearing

Bearing assembly

Bearing assembly with windmill body attached

Bearing Mount, Support Pole, Lynch Pin (to secure to mount to pole)

Lynch Pin Inserted

Windmill Mount all together (before painting and wiring)

Yesterday I painted the wood in the hope that it will help protect it from the elements (and allow the mount to last longer so this idea can be fully tested). Today the paint is fully dry so I can begin assembling the whole thing:
  1. First step is to run the wiring down the pole and out to the rectifier board
  2. Glue (epoxy) the axial bearing into the the wooden mount
  3. Place some type of cap over the top of the bearing assembly to prevent water, snow and ice from entering the pole

Below is a picture of how the wiring enters the support pole:

 I finally found a small plastic box for the rectifier board.  I added a plug so that I'd be able to change heating elements easily (just in case I come up with a more efficient configuration)
Hopefully I'll be able to run another live test tomorrow.