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Electrical Engineering · Q48

Transformers

Engineering and GATE · Electrical Engineering · question 48

Q48

In the transformer following winding has got more cross-sectional area

A.
Low voltage winding
Answer
B.
High voltage winding
C.
Primary winding
D.
Secondary winding

Answer: Option A

Solution

Answer: Option A
Solution:
A transformer is like a special device that helps to change the voltage of electricity. It has two main coils of wire, called "windings." One winding is where electricity comes in (primary), and the other is where it goes out (secondary).

The most important thing to remember for this question is: Power in a transformer stays almost the same!
Think of electrical power as the "work" being done. Power (P) is calculated by multiplying Voltage (V) by Current (I) (P = V x I).

1. If the transformer steps down the voltage (makes it lower), then to keep the power the same, the current must go up (become higher).
2. If the transformer steps up the voltage (makes it higher), then to keep the power the same, the current must go down (become lower).

Now, imagine a water pipe. If you want more water to flow through it (higher current), you need a wider pipe (larger cross-sectional area), right? It's the same for electricity!

* Wires that carry a high current need to be thicker (have a larger cross-sectional area) to avoid getting too hot and to allow the electricity to flow easily.
* Wires that carry a low current can be thinner (have a smaller cross-sectional area).

So, if the low voltage winding has a low voltage, it means it must be carrying a higher current to keep the power constant. And because it carries higher current, its wires need to be thicker, meaning they have a larger cross-sectional area.

The high voltage winding will have a lower current, so its wires can be thinner.

Options C and D (Primary and Secondary) are not always the answer because a primary winding could be high voltage or low voltage, and the same goes for the secondary. The crucial factor is the voltage level (and thus the current level) it handles.

Therefore, the winding with the more cross-sectional area is the Low voltage winding because it carries the higher current.

Correct Answer: Option A: Low voltage winding