gcsescience.com                                                    13                                                    gcsescience.com

Electromagnetism

Electric Motor.  The Split - Ring Commutator.

A split - ring commutator (sometimes just called a commutator)
is a simple and clever device for reversing the current direction
through an armature every half turn (see previous page).

The commutator is made from two round pieces of copper,
one on each side of the spindle.
A piece of carbon (graphite) is lightly pushed against the copper
to conduct the electricity to the armature.
The carbon brushes against the copper when the commutator spins.

As the motor rotates, first one piece of copper, then the next
connects with the brush every half turn.
The wire on the left side of the armature
always has current flowing in the same direction,
and so the armature will keep turning in the same direction
(see previous page).

The pieces of copper are held apart in the centre
and do not touch each other.
They look like a ring of copper which is split down the middle
This is why it is called a split - ring commutator.

     Headings     Electromagnetism      Search      Questions     

gcsescience.com              Contents             Index              Quizzes             gcsescience.com

Copyright © 2008 Dr. Colin France. All Rights Reserved.