What is OCC in 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 OCC alternator?

Thus Open Circuit Characteristic or OCC is basically the plot between the armature terminal voltage Ef versus field current If while keeping the speed of rotor at rated value. Figure below shows the connection diagram for performing the Open Circuit Test of Alternator.

Why we do OCC test?

Open Circuit Test The purpose of the open-circuit test is to determine the no-load current and losses of the transformer because of which their no-load parameters are determined. This test is performed on the primary winding of the transformer.

What is OCC and SCC test of generator?

As the internal generated voltage EA is measured from the OCC at that point where the generator is partly saturated for a higher value of the field current and the armature current (IA) taken from the SCC where the generator is un-saturated for all values of the field current.

What is OCC test?

OCC’s Technical Certification Services provides testing support for external business parties including Banks, Clearing Members, Non-Clearing Organizations and Trade Sources.

What is yoke in DC machine?

Yoke: The outer frame of a dc machine is called as yoke. It is made up of cast iron or steel. It not only provides mechanical strength to the whole assembly but also carries the magnetic flux produced by the field winding. The armature is built up of thin laminated circular steel disks for reducing eddy current losses.

What are OCC characteristics?

Open Circuit Characteristic (O.C.C.) (E0/If) 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.

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.