unusual motor very interesting

[siliconmix]

[G7PSK]

Those bearings wont last very long, I can hear them rumbling already.

[MikeK]

He's passing current through the bearings?  Oh gawd.

I think Honda had a problem a while back where the electrical system was grounding through the front wheel bearings, causing them to wear out well before their time.

[mikeselectricstuff]

Fun but utterly useless - More info here :
http://electricstuff.co.uk/bbmotor.html

[Unclegummers]

Is that FREE ENERGY?!?!

[Mechatrommer]

Is that FREE ENERGY?!?!

free energy to the air. 25A to get a usefull rotation? my car cigarette lighter butt is better.

[siliconmix]

Fun but utterly useless - More info here :
http://electricstuff.co.uk/bbmotor.html

is that your site mike ? .but what if every other bb is a magnet ? pmsl

[G7PSK]

If I read the operation principle correctly as the bearings heat up the whole thing will become less and less efficient to the point that when the balls are as hot overall as they can get before melting and there fore no more thermal expansion and more importantly enough residual heat to prevent rapid contraction after the expansion it will grind to a halt.

[SeanB]

I have done that, it works well, if rather inefficiently. Just remember to use steel endcap bearings, or remove the rubber endcaps, otherwise there will be fun. Works best using a 12V car battery, and around 5m of 2.5mm bare steel wire as a ballast resistor. The wire glows red during startup ( until you move the shaft to start) and then cools down to just burning hot but not glowing. The motors generally will run for 5 minutes before something fails, either the cage melts, the balls drop out or the raceway arcs enough to seize.