Strategy to prepare DC Machines?

Dear Engineer's,

In this article I'll share how to prepare DC Machines. 

DC Machines

Now let us discuss some important topics from DC Machines that you need to prepare for GATE Exam.

This chapter starts with the construction of DC machines such as the construction of Core as well as the construction of Armature winding which is divided into two categories lap winding and Wave Winding. If you remember the features of each of the windings then you need not go into the details of the construction of each type of winding.

The theoretical concept which is Important from the GATE point of view as well as interview point of view

The concept of Armature reaction and Commutation.

DC Machines

These concepts are given an insight into the problems faced by the DC machine in its operation.

From, the numerical point of view, this chapter totally revolves around 4 equations which are two performance equations one each for generator and motor and the expressions for Torque and EMF. The most commonly asked questions based on speed of DC Motor and we must always remember that whenever we want to calculate speed we need to calculate the back emf and then take the ratio of two emfs to compute the ratio of two speeds.

Other than that the concepts such as Efficiency and Maximum Efficiency are important for GATE relevant problems so here also you need to understand the various losses encountered in DC Machines. The difference from Transformers here is that we have Rotational Losses as well in the Rotating machines.

Then the concepts of Characteristics of DC Generator and Motor are not very much relevant to GATE and are generally asked in other examinations. The concepts such a starting and braking of DC Motor are also not very much relevant to GATE exam.

In general, the questions are mostly based on Speed Control of DC motors. So practice as many problems as possible based on this concept.

In forward article I'll share about Induction Machines, I hopefully this could be handy for your preparation. Feel free to ask your queries in comment box.

Thanks & Regards

Nani

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