What is short circuit test in synchronous machine?

Short-Circuit Test Set the field current to zero. Short circuit the armature terminals. Drive the generator at synchronous speed with external mechanical system. Slowly increase the field winding current until the short circuit armature current reaches the rated design value.

What is open circuit test for synchronous generator?

Open Circuit Test: This test is used for determining the synchronous impedance. The alternator is running at the rated synchronous speed, and the load terminals are kept open. The excitation current may be increased to get 25% more than the rated voltage i.e. up to 125% of the rated voltage.

What is OCC and SCC test?

Open circuit characteristic (OCC) and Short Circuit Characteristics (SCC) of a Synchronous generator.

What is short circuit test in generator?

The short-circuit test provides information about the current capabilities of a synchronous generator. It is performed by driving the generator at its rated speed when the terminals of the armature winding are shorted. An ammeter is placed in series with one of the three shorted lines.

What is open circuit characteristics of synchronous generator?

Open-circuit characteristic (OCC) of a generator The OCC follows a straight-line relation as long as the magnetic circuit of the synchronous generator does not saturate. Since, in the linear region, most of the applied mmf is consumed by the air-gap, the straight line is appropriately called the air-gap line.

How can you determine the open circuit characteristics of synchronous generator?

For getting the Open Circuit Characteristics of Synchronous Machine, the alternator is first driven at its rated speed and the open terminal voltage i.e. voltage across the armature terminal is noted by varying the field current.

What is short circuit ratio of synchronous machine?

The short circuit ratio (SCR) of a synchronous machine is defined as the ratio of the field current required to generate rated voltage on an open circuit to the field current required to circulate rated armature current on a short circuit.

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 short circuit ratio of a synchronous machine?

What is the characteristics of short circuit test?

A short circuit is a direct connection between two terminals. The short circuit maintains zero voltage drop and can allow any current, so its I-V characteristic is a vertical line at V=0.

What precautions you should take during the short circuit test?

Keep the auto transformer output at its minimum voltage position and switch on the AC supply. Increase the applied voltage very slowly, and adjust it to get the current equal to the rated value of the winding. Do not increase the applied voltage further.

What is open circuit test of synchronous machine?

Open Circuit Test and Short Circuit Test are performed on a Synchronous Machine to find out the parameters of Synchronous Machine and hence to have an idea of their performance. Open Circuit Test of Synchronous Machine is also called No Load, Saturation or Magnetizing Characteristics for the reason which will be clear after going through the post.

What are the characteristics of synchronous machine?

Open Circuit and Short Circuit Characteristics of Synchronous Machine. For getting the Open Circuit Characteristics of Synchronous Machine, the alternator is first driven at its rated speed and the open terminal voltage i.e. voltage across the armature terminal is noted by varying the field current.

What is the short-circuit characteristic of a synchronous generator?

This graph among the field current and the armature current known as the short-circuit characteristic (SCC). You can see that it is a linear graph. To understand this straight-line behavior let’s have a look at the equivalent circuit of the synchronous generator when it is short-circuited this circuit is shown below.

How do you perform a short circuit test?

Short-Circuit Test. As the name suggests, the short circuit test is carried out with the terminals of the machine short circuited. The basic test procedure is as follows: Set the field current to zero. Short circuit the armature terminals. Drive the generator at synchronous speed with external mechanical system.