Indexing the Backing Plate

Once the magnets get mounted, it’ll be imperative that these rotors be assembled properly oriented to each other. We drill a small divet (not all the way through) on the back side of each rotor where the 1st magnets will be mounted as an index mark to ensure the correct alignment of the rotors to each other now, and in case the machine ever needs to be disassembled in the future. 
 

Magnet Layout
A blank rotor is on the left and the one on the right has the magnet template laid over it. The magnets are in between with the spacers used for shipping them. They are not toys and are so much stronger than a regular magnet that I was unable to pull them apart - even with the plastic spacers between them.

A safe way to separate them is to place the entire “bar” on the workbench with just one magnet overhanging the edge. You can then forcibly slide the overhanging magnet down and away from the rest, but even then it’s a blood-blister inducing ‘pinch’ waiting to happen. ;)

Magnet Template
Using a table of sides angles and sides, I divided a circle into 12 equal sections (This is the same method we used to divide a circle into 9 equal sections for the coil placement in the stator). Since the magnets are 1″ x 2″ (and 1/2″ thick) I drew the layout on a piece of 1/8″ plywood (because it’s non-magnetic & I want to be able to remove it) and I cut it out with the jig-saw. The four 1/2″ holes in the center line up with the 1/2″ mounting stud holes in the rotor.

The temple get’s placed on each baking plate and the first magnet is installed. The up-side polarity of the 1st magnet on the first rotor is irrelevant, but each consecutive magnet needs to be placed in it’s location with an alternate pole facing up and the opposing magnet on the next rotor has to have the opposite pole facing  up – otherwise the machine will not produce electricity and all of this will be for naught. :(

A Magnet Rotor with 12 magnets alternating their facing polarity in a N-S-N configuration and some CA glue to hold them belt-and-suspenders secure until we cast it in epoxy fiberglass just like the stator.

Both rotors have 4 half-inch holes on a 4″ circle for mounting, but only one has the 7/16″ threaded holes interspaced for the “jacking bolts”. With 12 of those magnets on each plate, we’ve created an assembly that will do far more than just pinch our fingers and we’ll need a safe way to be able to construct and disassemble the machine without breaking any appendages or causing any bleeding. ;)

The 2nd rotor is constructed in like manner but ensuring the first magnet’s up-side polarity on this rotor is the opposite of the the one at the divet of the 1st rotor.  Following the N-S-N alternating pattern will guarantee that the entire assembly is constructed with magnetic faces in opposition.

As a last confirming check, take a regular household magnet and hold it over each magnet on each rotor. It should alternately attract and repel as you work your way around. If it doesn’t, now is the time to knock it loose and correct it – before casting it in the epoxy resin.

Tags: Wind Turbine

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