A
direct current (DC) motor is a simple electric motor that uses
electricity and
a
magnetic field to produce
torque , which turns the motor. At its most simple, a DC motor
requires two magnets of opposite polarity and an electric coil, which acts as an
electromagnet .
The repellent and attractive electromagnetic forces of the magnets provide the torque that
causes the DC motor to turn .
If you've ever played with magnets, you know that they are polarized, with a positive
and a negative side. The attraction between opposite poles and the repulsion of similar
poles can easily be felt, even with relatively weak magnets. A DC motor uses these
properties to convert
electricity into motion .
It is based on the principle that when a current-carrying conductor is placed in a magnetic field,
it experiences a mechanical force whose direction is given by
Fleming's Left-hand rule and whose
magnitude is given by -
Force,
F =
B I l newton
Where
B is the magnetic field in
weber/m2 .
I is the current in
amperes and
l is the length of the coil in
meter .
The force, current and the magnetic field are all in different directions.
If an Electric current flows through two copper wires that are between the poles of a magnet,
an upward force will move one wire up and a downward force will move the other wire down.
