Electromagnetism

Electric Motor.  What is a 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 the previous page).

Split-Ring Commutator

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 the 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.

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