A magnetic void (null spot) is created on a portion of inner hole of a ring magnet by absorbing North and South poles in that portion using small disc magnets having diameter equal to top and bottom surface width of ring magnet.
When a steel ball or spherical magnet is kept in that void, it moves away from the void towards stronger flux area (attraction). When small magnets are moved on the surface of ring magnet, the void also moves making the ball also to move on the inner hole.
Very interesting thing here is, the motion of the ball does not exert reactive force on the moving small disc magnets. It only tries to move away from the moving void on the inner hole. Which means that the output energy developed by moving ball is independent of the input energy supplied to move the disc magnets. The reactive force of moving ball acts on ring magnet which is kept stationary hence it (reactive force) is absorbed.
If the disc magnets are mounted on a wheel and moved parallel to the surface of ring magnet without touching the ring magnet, the energy required to move the disc magnets is almost negligible whereas the steel ball moves from void to stronger region with a huge attractive force. The surface of the ring magnet should have uniform magnetic field in a parallel plane. If some portion of the ring magnet is stronger than the rest, then moving disc magnets experience force creating a sticky point.
The present day motors which work either on the principle of rotating magnetic field (AC motors) or Ampere's rule (DC motors) have to do work against reaction hence their efficiency is less. If motor is built on the above described principle, the rotor only moves away from the magnetic void hence work is not done against reaction and hence efficiency will be very high.