Featured Project (notebook pages):

Frank Stenger's "Egg of Columbus" Motor Demo

Frank's comments:

I think I mentioned that I had a 2-pole pump motor I rescued from my
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 motor.
    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.  You
    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 bore.
    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 I showed
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.