RACA Spin Tests

[WXYZCIENCE]

This is the second RACA rotor completed and covered with a 2" non-magnetic .01" stainless steel band. The shaft is recycled from an old deep well pump. It is splined and will be easily coupled to the drive device.





There is only 1.5 cubic inches of N40 magnets in the rotor. The stainless steel screws tighten and hold the 16 magnets in place.


The coils pictured next are several types that were tested and recorded.






A side view shows the thickness or height of the coil.




Because the rotor spins very true I was able to close the air gap from the rotor to the windings to .025 of an inch. The tests were done on my drill press with a single coil. Readings were AC Volts across a 6 volt automotive bulb and AC Current through the 6 volt bulb.


Coil------RPM------Volts-----Amps


-#1-------600-------3V ac-------1.68A ac


-#1-------990-------4V ac-------2.63A ac


-#2-------600-------1.5V ac-----1.5A ac


-#2-------990-------2.9V ac-----2.15A ac


-#3-------600-------1.44V ac----1.28A ac


-#3-------990-------2.77V ac----1.87A ac


Using coil #1 design my voltage accross 16 coils  at 600 rpm will be:  48Volts Ac. 1.68Amps  80 watts ac.


Compared to the air 403 which puts out 81 watts at 600 rpm.


There was very little difference between coil #2 and #3 this was to my surprise . It seems to make little difference when the height was changed. Other than that. my test unit performed as expected. The total cost was $60.00 for magnets and wire and plastic. I expect the unit to be completely assembled before weeks end. I have enjoyed building and posting the results. Please feel free to copy my design and enjoy.
Joseph.

[vawtman]

Very nice Joe

 Just imagine big ole n50s in there or yours doubled up.

[windstuffnow]

  Really nice Joseph !  The small one and now the larger one I just completed has definately sparked my interest in them.  I'd like to build an internal stator using a plastic drum.  I think it could be done just as simple and still retain the cooling.  

  I actually have a considerable amount more invested than you do in the assembly.   Magnets, plastic, bearings and misc I'd say around 140.00.  Still about a buck a watt overall and if I rewind it with 14AWG I could get that down to about 25 cents a watt.  

  I ended up with about .060" gap from the magnets to the wire because of the spacer sheet between the drum halves.   Just wasn't any room for spacer pins since the coils are so close to each other.  

  Definately a fun project!  Thanks to you I'm hooked.   I started on the project last Wed and was only able to put a couple hours at a time into it.   Over all I'd say I have about 12 hours invested in the alternator from raw materials to a testable structure.  Doing the same project again ( and better plastic ) I bet this could be built in a day.

  Well, off to do some lathe tests with it just for fun...

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