When a current carrying wire is put between magnetic poles, the magnetic field around the wire interacts with the magnetic field it has been placed in. This causes the magnet and the conductor to exert a force on each other, resulting in the wire to move. This is called the motor effect.

To be at full force, the wire has to be 90 degrees to the magnetic field. If it is parallel, there will be no force, and any angles in between will only experience some force.

The magnitude (strength) of the force increases with the strength of the magnetic field. The force also increases with the amount of current.

The size of a force can be calculated by using this formula:

Force=Magnetic Flux Density X Current X Length

The MFD is the amount of field lies in the region, and shows the strength of the field.