What is Critical Field Resistance of DC Shunt Generator ? It is defined as the amount of field resistance required to generate emf in the armature winding. (or) The critical field resistance is defined as the field resistance of…

Generally, Swinburne's test is the most popular testing method of dc machine to determine losses and efficiency. It is an indirect method of testing a dc machine performed without actually loading the machine. Since it is a n…

In the last article, we have seen Swinburne's Test of dc machine, where the efficiency and losses are determined without applying actual load on the machine. It is an indirect method of testing a dc machine. Now let us see an…

Armature winding is the essential part of any electrical machine (motor or generator). The emf or voltage will be induced in the armature winding in the case of a generator, while it produces torque to rotate the shaft in the cas…

In a dc machine, the given input energy will be not equal to output energy i.e., the output energy will be always less than the input energy, thereby reducing the efficiency. The whole electrical input is not available at the mec…

In the last article, we have seen the phenomenon of armature reaction in a dc generator . There are various effects in the dc generator due to armature reaction. Due to the demagnetizing effect of armature flux on the field flux,…

In the last article, we have seen the working principle of dc generator and how we obtained the dc voltage at the output terminal. Now let us see the armature reaction of a dc generator. What is Armature Reaction ? In a dc gen…

When the field winding of a dc generator is excited, a flux with uniform distribution in the air gap of the dc generator is produced. Once the generator is loaded, load current flows through the armature conductors and set up its…

It is seen that emf induced in the armature conductors of a dc generator is alternating in nature. The frequency of the induced emf alternates with a frequency corresponding to the product of the speed and the number of pairs of …

Hopkinson's test of dc machine also known as a Regenerative Test. This test is also one of the efficient ways of determining the losses and efficiency of a dc machine. The test is performed by mechanical coupling of two ident…

For small ratings of dc machines, we can perform the tests directly by loading. In the case of large dc machines, it is difficult to perform tests by loading directly. For this purpose, there are indirect methods of testing a dc …