The Motor Effect

Current-carrying conductors in magnetic fields experience a force. This is known as the motor effect.

This force results from the induced magnetic fields of the moving charges interacting with the external magnetic field surrounding the conductor.

Motor Effect Right Hand Push Rule

The force on a conductor (length L) at angle θ from perpendicular to a magnetic field is given by the following:

F=LI_\perp B = LIB\sin\theta

The right-hand push rule (see right) should be used to determine the direction of the applied force.

  • Max. force is produced where the conductor is perpendicular to the magnetic field
  • There is NO force when the conductor is parallel with the magnetic field, i.e. aligned in the direction of its field lines