Dynamically induced E.M.F

 Dynamically induced E.M.F

A Generator is a rotating machine, which converts mechanical energy supplied to it into electrical energy. For production of dynamically (or statically) induced e.m.f the following three things are essential.

1.    Magnetic field (flux)

2.    Conductor (or coil ) and  

3.    Relative motion between field and conductor.

In D.c. Generators the flux is produced by the stationary field magnets. Where as conductors are situated on the periphery of the armature being rotated by the prime mover, the e.m.f  induced in the armature conductors, according to faradays laws of electro magnetic induction and is known as dynamically induced e.m.f. The arrangement of field system and conductors is vice-versa in a.c. generators or alternators.

Flemings Right Hand Rule

Flemings Right Hand Rule is Used to determine the direction of induced currents in a conductor/coil (i.e. in generators). “Place the fore-finger (first finger), middle-finger (second finger) and thumb of the right hand mutually perpendicular to each other such that, the fore-finger should point the direction of magnetic field and thumb should point the direction of motion of the conductor then the middle finger gives the direction of induced current flowing in the conductor.”

Electromechanical energy Conversion

The chief advantage of electrical energy over other forms of energies is the relative ease and high efficiency with which it can be transmitted over a long distance. Electric energy is seldom available naturally and is rarely used directly. Its main use is in the form of a transmitting link for transporting other forms of energy e.g. light, mechanical, heat, sound etc., from one physical location to another. Obviously two kinds of energy conversion devices are needed-to convert from one form of energy to the electric form and to convert from one form of energy to the electric form. Our aim in this article is to understand the devices used for electromechanical energy conversion.

These devices can be

1.      Transducers for processing and transporting low-energy signals.

2.      Production of force or torque with limited mechanical motion like electromagnets, actuators, relays etc.

3.      Continuous energy conversion devices likes motors, generators for bulk energy conversion and utilization.

We concentrate on the principles of electromechanical energy conversion and the analysis is placed on the analysis of systems which use magnetic fields as the conversion medium. However, the analytical techniques for electric field systems are quite similar. The purpose of this analysis is three fold: