Dia. Mag. Alternator

[z.monkey]

Still having problems with the rotor, but I did get them to stick long enough to run a test.  I had found that two of the magnets had popped loose.  Eager to test, I glued the two loose magnets back on using the same 5 minute epoxy.  While I was testing another magnet popped loose.  But I did get to run it, get a video, and finally start to realize the potential of DiaMag8.

For this test I am hooking up the motor directly to the 12 Volt battery, no speed control.  The output of the alternator is around 15.5 Volts open circuit.  Then I am using a 1 to 10 step up transformer to boost the voltage up to where I can power a 120 Volt bulb.  The output voltage of the transformer is 151 Volts open circuit, and around 71 Volts loaded with a 10 Watt 120 Volt bulb.  While the test was running another magnet popped loose and crashed into the stator.  Uulgh, so I need to rework the rotor, again...

Here's teh video...

http://www.youtube.com/watch?v=KsOjhwYOQ4U&feature=channel_video_title

[z.monkey]

OK, reworking the rotor...

First I had to break off all the magnets.  Not surprisingly this was not too difficult.  The cheap 5 minute epoxy was not too hard to break.  I used a chisel and the palm of my hand to break the magnets loose, blech...  Then I needed to remove the failed epoxy from the magnets and rotor.  Mainly I was able to do this with my fingernails, double blech...

I figured I could increase the adhesion on the rotor by roughing up the surface of the rotor.  So, I chucked up the rotor in the drill press, and used a coarse rasp to rough it up.  This action also removed any old residual epoxy from the rotor.  The process also removed some aluminum from the rotor.

This time I am using an industrial grade marine epoxy.  Its viscosity is greater, and hopefully the adhesion is greater.  I reassembled the rotor clamp jig that I used before to hold the rotor while I am gluing the magnets.  Its basically just a couple of scrap 2x4s clamped to the bench.  Then I used some cable clamps to hold the ends of the shaft to the 2x4s.  I get all the magnets lined up on the fridge to help the process when I am sticking the magnets to the gooped up rotor.  The epoxy working time is 50 minutes for this variety, so I am not too worried about time.

Then the epoxy gets mixed and schmered evenly across the outside diameter of the rotor.  Its a good idea to get the epoxy as evenly distributed as possible to get all the magnets coated evenly.  Then I start applying the magnets, taking care to get them in order, NSNSNSNS.  The magnets will let you know if they are in the wrong order because they will not want to sit next to each other if you get like poles next to each other accidentally.  After placing the magnets I spend a while cleaning the excess epoxy off the rotor and magnets.  This epoxy sets in 50 minutes, but I am going to let it cure for a full 24 hours before I spin the rotor.  Just trying to get a full, solid cure before I put any stress on it.

Can't wait till tomorrow night...

[z.monkey]

Here is a better detail view of the 2nd Rotor Assembly...

[z.monkey]

The new rotor is working good...

http://www.youtube.com/watch?v=2AlMPDWqAMA