Tag: physics

A dynamo is a device which converts mechanical energy into electrical energy. 

Dynamo consists of horse-shoe magnet, armature coil, two slip rings, two carbon brushes, external circuit/load

Dynamo produces DC as output while transformer can be used to step-up or step-down AC voltage only.

Output emf is induced in armature coil which delivers power to the load.

DC motor is a device which coverts electrical energy into mechanical energy. It employs Fleming's left hand rule.
DC generator converts mechanical energy into electrical energy in from of DC. It employs Fleming's right hand rule.

The EMF generated by Faraday's law of induction due to relative movement of a circuit and a magnetic field is the phenomenon underlying electrical generators. When a permanent magnet is moved relative to a conductor, or vice versa, an electromotive force is created. If the wire is connected through an electrical load, current will flow, and thus electrical energy is generated, converting the mechanical energy of motion to electrical energy.

The frequency of AC current produced is same as the frequency of rotation of dynamo which is given 100 cycles per second that is $100Hz$.

Induced voltage in the rotating loop is given by   $\mathcal{E} = NBAw \ \sin wt$
where $N$ is the number of turns in the loop, $A$ is the area of the loop, $B$ is the magnetic field and $w$ is the angular speed of rotation of loop.
$\implies \ \mathcal{E}\propto w$
So, the induced voltage increases on increasing the speed of rotation of loop.

Generator is the device used for the production of electric current.