Electrified! How I met my Interests? (Part 2)
“Transformers. The core is a stack of thin silicon-steel lamination” — I still remember learning these lines by-heart. In this article, we’ll look into the construction of transformers and how the core is laminated. Before we begin, let’s discuss the answer to my question in the previous part. (https://medium.com/@asif.n.s/electrified-how-i-met-my-interests-part-1-d5f5bfb1a900)
Suppose a 1000 L water tank takes 20 minutes to get filled. Why does it take more time during the peak hours to fill the tank?
Loads can be categorized mainly into three; as resistive, capacitive and inductive loads (In practical cases, loads are a combination of all these). An electrical motor can be considered as an ‘inductive’ load. So what is this inductive or what is an inductor?
‘An inductor, also called a coil, choke or reactor, is a passive two-terminal electrical component that stores electrical energy in a magnetic field when electric current flows through it.’--Hail Wikipedia!
It was my dad who introduced me to inductors. He told me, “Consider an inductor as a seat belt. Seat belts resist sudden movements, you’ll only be able to pull it slowly. In the similar manner, an inductor opposes the sudden movement of current. So the loads which resist changes in current and if the current drawn, lags the voltage, it can be called an inductive load.”
Now, back to the question; during peak hours, the voltage decreases. Electrical motors being an inductive load tries to maintain it’s power output by increasing the current it draws(Think about the equation Power (P)=Voltage (V)*Current (I); when V decreases, I is increased to maintain the power P). Here, the excess current drawn is lost as heat and the amount we pay to the electrical utility is for the losses and not for our power requirement. Using inductive loads during peak hours is costly and reduces the lifetime of the machines. Hence it became a saying, “Do not switch on the water motor during peak hours!”
Optimus Prime of Electrical Engineering: Transformers
Let’s roll back to Shoranur. The second day was more fruitful for us. Our engineer told us, “You are the bengalis here. There’s no difference between you and the staff at the workshop for the coming days. Be ready to fall in love with grease and get dirty”. Even though the idea of bunking sessions and watching movies collapsed, the level of motivation in the previous day made us excited. We were divided into teams of four and each team had a faulty transformer assigned. Our task was to determine the fault, open the tank, collect the oil, and remove the winding from the tank.
We learned about transformer core laminations in our machines class. Whenever I heard about laminations, I imagined it as a solid structure with thin openings which prevents the formation of eddy currents.
We opened the transformer assigned to us, collected the black greasy oil and removed the core from the tank using a crane. The first step was to remove the ‘I’ lamination from the top part of the core. This moment was very special for me, as I realised that the laminated core is not a solid core with openings in it but thin sheets which are placed together. This small realisation helped me link my scattered ideas about induced voltages in the iron circuit, circulating currents(eddy currents), energy and heating losses, magnetic coupling between the coils, magnetic losses and a lot more.
Every engineer must be passionate to learn. Our learning starts with books, but I realised that the ‘urge to learn’ starts from the day we get our hands dirty. TMR Shoranur gifted us with this skill, the most necessary skill for an engineer today is ; ‘Urge to Learn’. An individual cannot master everything they learn, but they can master a specific area based on their interests.
Let me be very simple and clear; I randomly started learning about transformers, an internship helped me get clarity about the concepts, transformers became one among my area of interests. In short; Pick, Learn, Try, and Master!
There are a few tests that are to be done inorder to get a rough idea about the damage and the method of repair. I will not be writing about the tests that were done; If you are interested to learn more, please visit TMR Shoranur or visit the links below:
Transformer Construction: https://www.youtube.com/watch?v=H2hYUu8lPY0
Working & Concepts: https://www.electronicstutorials.ws/category/transformer
