First Coil

11 12 2008

coil1I ended up using ruby-serial to control embedded code in the Arduino. The problem with the wrong number of steps per revolution was from packet loss, by slowing down my ruby program the error went away. I need to get some more test wire to wind a full torus now!

Coil Winder

5 12 2008

Here are the pieces for the coil winder, partially assembled.coil_winder11


you can see the grain of the rapid prototype: 

Already I can tell the bobbin is not well supported axially. I doubt it will be able to keep tension with 12 gauge wire. But we can test thinner wire on this iteration. 

Putting it together:


As expected, the axel needed reinforcement:



Doing some quick checks. The stepper motors are supposed to take exactly 400 steps to complete a revolution. However, when I program the bobbin to take 400 steps forward then 400 steps backward, it appears to come just short of a full revolution! WTF! It looks like it’s closer to 415 steps per revolution. But I can’t trust that number to be accurate over many revolutions.

I’m learning RAD, a gem for controlling the arduino from ruby. Very cool.

New Calculations

23 11 2008

Based on the new coil winding calculations, I am going to slim down the coils to hit a target of ~200 wraps. Now the coils appear to be proportioned like the coils on the WB6. Here is what the adjustment looks like:


  • coil_length: 116,309.299858263 mm
  • outside_radius: 242.487113059643 mm
  • wraps: 225
  • torus_midplane_radius: 192.693468865964 mm
  • donut_exterier_radius: 107.8 mm
  • torus_radius: 84.0 mm
  • donut_hole_radius: 60.2 mm
  • torus_tube_radius: 23.8 mm
  • torus_tube_hollow_radius: 18.802 mm
  • joint_radius: 16.66 mm
  • joint_negative_radius: 5.831 mm
  • torus_tube_wall_thickness: 4.998 mm

Next we will calculate Forces_between_two_magnetic_dipoles, and Power_dissipation of the coils in the form of heat. This will give us some idea of the tensile strength and temperature envelope of the device.

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