Homopolar Generators

[chainmailleman]

Would a spiral coil produce a higher voltage than a solid copper disk as the rotating conductor?

I have been over several different forums (energetic, OU, various yahoo groups, etc), youtube, and google and none have given me a straight answer.

Only 2 posters have claimed it does nothing, without any link to any experiment/source.

Without any verifiable evidence, I'm left to ponder on my own. I do have the capabilities of conducting the experiment on my own, however if someone else has replicated the experiment, why waste my resources only to come to the same result?

[chainmailleman]

If the voltage is dependent upon the angular velocity (rotations per minute), the strength of the field, and the radius of the conductor. Then logically speaking, by placing a spiral wound flat coil in place of the solid copper conductor, the radius (distance) of the conductor is increased significantly.

V = WBR^2
W = angular velocity
B = Magnetic field
R = Radius of conductor

[SmallTownGuy]

Since the EMF is radial to the spinning disk, replacing the disk with a coil shouldn't have any effect at all. The increase in path length should just be cancelled out by the spiral's winding angle.

You're welcome to try it, though. Maybe there's some other benefit (cost?) nobody's thought of.

[chainmailleman]

SmallTownGuy

Since the EMF is radial to the spinning disk, replacing the disk with a coil shouldn't have any effect at all. The increase in path length should just be cancelled out by the spiral's winding angle.

You're welcome to try it, though. Maybe there's some other benefit (cost?) nobody's thought of.

You may be right given electricity is a right angle phenomenon. I was thinking about other benefits as well and I think that with a coil of heavy gauge wire, one could remove the peripheral brush and place it on the axle where less surface area passes per rotation. Or when you stack them back to back so the current reverses in one coil, the peripheral brush(es) could be eliminated all together.

Not to mention copper wire/cable is cheaper than a solid 1/4" copper plate at 6" diameter.