Featured Project (notebook pages):
Frank Stenger's "Egg of Columbus" Motor Demo
I think I mentioned that I had a 2-pole pump motor I rescued
neighbor's trash. I took it apart and made a neat "Egg of Columbus"
kind of demo breadboard (I even mounted it on a board! :o).
I attached 4 photos as follows:
EggStator.jpg --- Shows the empty stator and windings from the
You can see the big running winding coils - one left and one right that
would cause flux right and left in this shot. This winding is hooked
right across whatever line voltage supply that's in use. (That's
12 volts for the board you see but I also tried it on 30 volts.)
Top and bottom you may be able to make out a smaller winding with
smaller wire nested over the ends of the two running coils. This is the
start winding that produces flux top to bottom in the shot. This
winding is connected to the line, but it has the 300 mfd elec. start cap in
series with it to give a large phase shift for better starting torque.
I have not measured the parameters for these windings yet, but whatever
they are they really provide a nice "spin torque" in the bore.
EggBoard.jpg --- Shows the general layout of the demo board.
can see the start cap and the 12 volt secondary transformer. Of
course, when you take the rotor out of a motor you introduce a huge
air gap across the bore - so the inductance goes way down and you
must make a drastic reduction in drive voltage to keep from burning
out the stator. With 30 volts on the stator it got hot in less than 30
sec, but on 12 volts it looks like it would run almost continuously without
too much problem.
EggCan.jpg --- Shows the Pepsi can I modified to spin in the
This is my "egg" so-to-speak. The can will spin around in the bore
and make a racket with no support at all, but it spins really nice
on the thin wire axle I stuck thru its ends. I cut out the top dome
because it was out of balance because of the "open tab" hole. I
replaced it with a disk of thin Al flashing held in place with duct tape.
This is really what I wanted to do with that other stator toroid
you, and I'm not sure I will have the guts to wind its coils when the
magnet wire I ordered gets here. If I did rewind that stator, it would
be nice and symmetrical with identical winding sets.
Note that if you put this latest stator around your CRT, you would
probably get the same traces as with the TV yoke. They are almost
equivalent except the yoke's field has probably been carefully designed
to give a nice linear deflection.