DC Electric Motor



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.

Current in DC Motor

Magnetic Field in DC Motor


Force in DC Motor

Torque in DC Motor

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