As you can see there are no coils and no magnets in this motor. It is believed that the instantaneous thermal expansion at the points of contact between the balls and the race gives the balls a torque.
In this engine bearings were used with a diameter of 12 mm. The current flowing through the circuit is about 40 Amps. The voltage is 2 Volts. The main power is released in the form of heat. The twisting moment is miserly. Therefore, such engine does not find any practical application.
If you doubt the operation of this mechanism, look for information on the on the Huber Effect.