First 199 words of the document:
The Motor Effect
The motor effect is the term used when a current carrying wire in the presence of a
magnetic field experiences a force.
The size of the force can be increased by increasing the current and using a
The size of the force depends on the angle between the wire and the magnetic
field lines. The force is greatest when the wire is perpendicular i.e. at a 90° angle
to the magnetic field. The force is zero when the wire is parallel to the magnetic
The direction of the force is always at right angles to the wire and the field lines.
Also, the direction of the force is reversed if the direction of the current or the
magnetic field is reversed. Fleming's Left hand rule can be used to show us this:
The Electric Motor
An electric motor is designed to use the motor effect. We can control the speed of an
electric motor by changing the current. We can also reverse the direction the motor turns
by reversing the current.