how torque is related to voltage or current

transfer function of dc generator pdf

Principle :

It is based on the principle of production of dynamically (or motionally) induced e.m.f (Electromotive Force). Whenever a conductor cuts magnetic flux, dynamically induced e.m.f. is produced in it according to Faraday's Laws of Electromagnetic Induction. This e.m.f. causes a current to flow if the conductor circuit is closed.

Hence, the basic essential parts of an electric generator are :

A magnetic field and

A conductor or conductors which can so move as to cut the flux.

Construction :

A single-turn rectangular copper coil abcd moving about its own axis in a magnetic field provided by either permanent magnets or electromagnets. The two ends of the coil are joined to two split-rings