Homopolar Generators Help

[dtaker]

This is the simple generator first discovered by Faraday, over 150 years ago.  Then lately experimented with famous researchers like Bruce de Palma and claimed it to have overunity of over 100%...
For brief intro: http://jnaudin.free.fr/html/farhom.htm

I have a question for anyone who's familiar or have worked with this...  I've constructed something different, instead of the magnets rotating with the aluminum disc, the magnets are stationary and the aluminum is spun at 10,000 rpm.  The magnets are adjustable so I can put them close or put them away from the aluminum disk.

When the magnet is put close to spinning disc, the disc slowed significantly, from 10,000 rpm, it went to about 6,000 rpm.  Has anyone experienced this 'drag' when you spin aluminum disc against magnets?  The researchers also claimed that this drag exist even if you rotate magnets with the disk..  Would also want to know about the nature of this drag, is this due to magnetic induction or something else, thanks 

Sorry, I have to post this thing here, can't find anyplace else to post, thanks for your time, BTW, I'm new here, looking forward for some involvement in this forum soon

[hartiberlin]

Yes, it is a magnetic brake ! The  eddy currents inside the alu-disc have a drag back effect on the magnet field from the magnets.

Standard effect, no new science.

Regards, Stefan.

[dtaker]

Thanks Stefan, for clearing this.  This braking is sometimes strong enough that if you put a rapidly spinning alu disc beside a magnet, it pushes the magnet away  No it's not aerodynamic in nature.

Would to ask a few more, What if I use copper instead of aluminum? would I get the same effect?

I hear the magnetic field of a disk magnet (polar axis same as physical axis, one pole on each side) doesn't change whether you rotate it on it's axis or not, the field doesn't rotate too, it remains stationary.

If I rotate the disc magnet near alu- disc at same velocity, will I still get this braking effect exclusively for the alu disc if the theory above is correct(not sure)?

Thanks for the time.

[Paul-R]

Most work, certainly the Paramahamsa Tewari and Bruce Depalma machines have the mag fields rotating with the Al disc. Even the odd device in the new US Navy warship, the Type DDX, has a superconducting coil which rotates.

I believe depalma had a late variant with two devices facing one antother, one running clockwise and the other anticlockwise. Stefan reckons this work is rubbish, but I find it hard to believe that a Project Manager at a nuclear power station would either falsify readings or get them wrong.
Paul.

[pucella]

Hi
Try to drop a strong neo magnet through a vertical copper pipe, you will by very surprised.
Best regards George