What are the differences between a DC motor and an AC motor?
Release Date:16/05/2016
A DC motor works in the same principle
as an AC motor, with a mechanism to allow it to rotate even if the
supply is not alternating. After all, simple motors work because the
the direction of current reverses (alternates) every half cycle,
rendering the armature to rotate. Now why does the current have to
alternate to allow for rotation? The left hand motor rule will show you
their relation. I'll elaborate on that later.
Of course, as
mentioned earlier, DC motors will also rotate only when the current
direction changes, although the supply is unidirectional. The commutator
is the mechanical device that allows the current in a conductor to
reverse its direction.
To understand intuitively, read on:
AC
means the direction of current is reversing every half cycle, about 100
times a second if it is a 50 Hz supply. DC just means the current is
maintaining the same direction. As a principle, the current direction must change, in order for the motor to actually rotate. Why? Because the direction of current and the direction of motion of conductor are related - Take left hand rule for motors.
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