Why short circuit characteristics is a straight line?

The short circuit characteristic is linear. The flux density in the machine is very low since the terminal voltage is zero. The air-gap flux is sufficient to produce a voltage to overcome the leakage reactance drop. From these two curves, the synchronous reactance can be found.

Why OCC is curve initially straight and then curve?

Initially OCC follows a straight-line relation with the field current as long as the magnetic circuit of the synchronous generator does not saturate. This straight line is appropriately called the air-gap line. Practically due to saturation induced emf bend from the straight line.

Why the OC characteristics is not linear?

Because of saturation in iron parts of machine, the no load generated voltage Ef does not increase in the same proportion as the increase in field current and hence the OCC of Three Phase ALternator in Non-Linear.

Why open circuit characteristics of a DC generator is not a straight line?

follows a straight line. However, as the flux density increases, the poles get saturated and the ɸ becomes practically constant. Thus, even we increase the If further, ɸ remains constant and hence, Eg also remains constant. Hence, the O.C.C.

What is the open circuit curve of a synchronous machine?

As synchronous machines operate at effectively constant speed, the open circuit voltage test provides the relationship between field current and induced voltage for all load conditions. The induced open circuit voltage is sometimes known as the “excitation voltage”, or even simply as the “excitation”.

What is open circuit characteristics of synchronous generator?

What is open circuit characteristic?

In a separately excited DC generator, the field winding is excited by an external. independent source. There are generally three most important characteristic of DC. generator: Magnetic or Open Circuit Characteristic of Separately Excited DC Generator.

Why OCC is also known as magnetization characteristics?

A typical Magnetization Characteristics is shown in Fig. 7.20. It is known as open-circuit characteristic (OCC) because of the method by which it is determined. It exhibits all the important characteristics of the magnetization curve of iron, modified by the presence of an air-gap in the magnetic circuit.

https://www.youtube.com/watch?v=2O_M4JlbxAM