Why OCC is called as no load magnetization characteristics?

Open Circuit Characteristic (O.C.C.) Open circuit characteristic is also known as magnetic characteristic or no-load saturation characteristic. This characteristic shows the relation between generated emf at no load (E0) and the field current (If) at a given fixed speed. The O.C.C.

What is meant by OCC of a DC generator?

The open circuit characteristics (O.C.C) or magnetization characteristics is the curve that shows the relationship between the generated EMF at no-load (E0) and the field current (If) at constant speed. It is also known as no-load saturation curve.

What is magnetisation characteristics of DC shunt generator?

It uses the voltage Ea generated by the machine to establish the field current If, which in turn gives rise to the magnetic-field flux Φ. When the armature winding rotates in this magnetic field so to cut the flux, the voltage Ea is induced in the armature.

What is mean by magnetization curve?

Definition of magnetization curve : a graph representing changes in the condition of a magnetizable substance with magnetizing force H as abscissa and either magnetization I or induction B as ordinate.

Which of the following characteristics reveal about the magnetization nature of the machine?

Which of the following characteristics reveal about the magnetization nature of the machine? Explanation: Both no-load and load characteristics are required to predict the magnetization of the machine.

What is the purpose of OCC test?

This plot is called open-circuit characteristic (OCC) of a generator. With this characteristic, it is possible to find the internal generated voltage of the generator for any given field current.

Why is OCC not on origin?

In an OCC at If =0, graph starts from origin. Explanation: As the machine would have been previously subjected to magnetization, a small residual voltage would be present with field unexcited. As will be seen practically, this is necessary for generator to self-excite.

Why is rh2 kept in maximum position at starting?

At the time of starting of motor, the armature resistance is kept at maximum position to control and reduce the high starting current and field rheostat atminimum position to ensure that speed does not go beyond rated value and to have high starting torque.