AN UNUSUAL MOTOR

[mariost]

CAN ANYBODY EXPLAIN HOW IT WORKS? I made it after following the instructions from a video in the net and actually it works. I cannot understand how it happens.
In this motor there are no coils , magnetic fields, magnets, and brushes.There are only two bearings connected by a metal axis.
The current flows through the first bearing, the axis and then the other bearing. The electrical power supply is connected to the outer rings of the bearings.

MOTOR PROPERTIES:
1. the engine must be first started. Cannot start alone with the current.
2. the motor rotates in either direction.
3. the engine is working both direct current and alternating current.The power is approximately 5 to 12 Volts with very strong current , about 20 or more Amps.(this is a short circuit and after a few seconds everything is too hot.)
There are different explanation. One of them is :
"In the ball bearing Motor" the current passes through inner race of one side ball bearing , then to the shaft , outer race of other ball bearing , then to inner race , causes a temporally expansion of each ball , deforms it to elliptical and adds pressure between inner & outer race then cause a moment of rotation , for that reason , it needs a prime movement to sustain rotation , by the way it doesn't matter whether the current is DC or AC , it just used to heat up the balls. WATCC THE VIDEO HERE: