On Jun 28, 2009, at 8:26 PM, Harry Veeder wrote:
Using a magnetic shaft might disrupt the effect, but I am only
guessing.
When I use the term magnetic I mean magnetic material like iron or
steel, not a magnetized material. If brushes are to be placed
directly on the circumference of the shaft then I say there is no
prospect of torque unless the shaft is magnetic - no hysteresis, no
torque.
How about if the leads were connected to the ends of a fixed shaft and
let the outer racers rotate instead? That would eliminate the brush
friction.
Harry
There would have to be brushes to the outer races - and thus the
friction would be there instead. Current has to make a closed loop.
The cool thing that would get lots of people the chance to first hand
experiment would be to locate a cheap source for non-magnetic
stainless steel bearings. Non-magnetic (relative permeability 1.01
or less) bearings exist:
http://www.nsk.com/products/spacea/non-magnetic/
but look pricey.
Here is a Thomas register list of suppliers of non-magnetic bearings:
http://www.thomasnet.com/products/bearings-ball-
nonmagnetic-3920402-1.html
http://tinyurl.com/lbe8ck
Here are some alternatives in the under $30 range:
http://www.thomasnet.com/catalognavigator.html?cov=NA&what=non-
magnetic+ball+bearings&heading=3920402&cid=270891&CNID=&cnurl=http%3A%
2F%2Fkmsbearings.thomasnet.com%2FCategory%2Fradial-ball-bearings-3
http://tinyurl.com/mk3o4d
Other types available in the same metals:
http://www.thomasnet.com/catalognavigator.html?cov=NA&what=non-
magnetic+ball+bearings&heading=3920402&cid=270891&CNID=&cnurl=http%3A%
2F%2Fkmsbearings.thomasnet.com%2FCategory%2Fradial-ball-bearings-3
http://tinyurl.com/mk3o4d
The key is to spend the time to locate really cheap non-magnetic
bearings that have identically sized and cheap magnetic counterparts.
The configuration I suggested in Fig. 5 of
http://www.mtaonline.net/~hheffner/HullMotor.pdf
was for scientific purposes - to isolate the source of the effect.
Using non-magnetic bearings as a control will only establish that
magnetic materials are required (or not).
The drawback of the Fig. 5 configuration is that one brush point
replaces 8 points from a single bearing and 16 in the overall motor.
The weakened motor also has to be able to push a conventional brush.
However, by sandwiching a thin grooved copper disk between two iron
disks, and using a copper shaft, the max current and force should
rise dramatically, so there are trade-offs. Construction is also more
difficult, but the scientific results available are improved.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
