Hi folks.
I think we didn't talk much about the heart of the power system itself - transformers.
The core of the transformer is a very important component of it and governs the operating character of the transformer.Let us talk something about the materials used for core. As we always say, It is not made up of silicon steel (popularly known as electrical steel). It is made up of something called- CRGO steel (Cold Rolled Grain Oriented Steel).
Well it is basically silicon steel but treated specially we can say. Addition of silicon to iron is important as it significantly increases the electrical resistivity of the steel, which decreases the induced eddy currents and narrows the hysteresis loop (area under B-H curve is proportional to the losses) of the material, thus lowering the core loss. However, the grain structure hardens and embrittles the metal, which adversely affects the workability of the material.
So this Si-steel has BCC structure - Body centered cubic structure (you can find this in some standard chemistry book or Google it). This crystal when subjected to magnetic fields can undergo magnetization in 3 ways (directions)-
1. Along the shorted edge of the cube
2. Along the face diagonal of the cube
3. Along the through diagonal of the cube
Studies show that shorter the length of axis of magnetization, lower is the reluctance offered. In the last articles, we have seen, to reduce magnetizing current permeability should be very high and that implies reluctance offered should be very low.
So we take special efforts to magnetize every crystal (almost) along the shortest axis that is the edge of the cube. This texture is developed by a series of careful working and annealing operations. Annealing, in metallurgy and materials science, is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and to make it more workable. It involves heating a material to above its critical temperature, maintaining a suitable temperature, and then cooling.
The question remains is why don't we use this superior materials for all the electrical machines such as induction machines or synchronous machines?
The reason is if we see the flow of flux in these machines, it is not unidirectional and uniform in sense like transformer. So the reluctance offered in one direction will reduce and other direction might increase and this will create a harmful imbalance.
If you are interested, search for amorphous core transformers that are still superior compared to these.
Thank you for your time and please feel free to leave comments about your areas of interest. I will surely try to post about them.
I think we didn't talk much about the heart of the power system itself - transformers.
The core of the transformer is a very important component of it and governs the operating character of the transformer.Let us talk something about the materials used for core. As we always say, It is not made up of silicon steel (popularly known as electrical steel). It is made up of something called- CRGO steel (Cold Rolled Grain Oriented Steel).
Well it is basically silicon steel but treated specially we can say. Addition of silicon to iron is important as it significantly increases the electrical resistivity of the steel, which decreases the induced eddy currents and narrows the hysteresis loop (area under B-H curve is proportional to the losses) of the material, thus lowering the core loss. However, the grain structure hardens and embrittles the metal, which adversely affects the workability of the material.
So this Si-steel has BCC structure - Body centered cubic structure (you can find this in some standard chemistry book or Google it). This crystal when subjected to magnetic fields can undergo magnetization in 3 ways (directions)-
1. Along the shorted edge of the cube
2. Along the face diagonal of the cube
3. Along the through diagonal of the cube
Studies show that shorter the length of axis of magnetization, lower is the reluctance offered. In the last articles, we have seen, to reduce magnetizing current permeability should be very high and that implies reluctance offered should be very low.
So we take special efforts to magnetize every crystal (almost) along the shortest axis that is the edge of the cube. This texture is developed by a series of careful working and annealing operations. Annealing, in metallurgy and materials science, is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and to make it more workable. It involves heating a material to above its critical temperature, maintaining a suitable temperature, and then cooling.
The question remains is why don't we use this superior materials for all the electrical machines such as induction machines or synchronous machines?
The reason is if we see the flow of flux in these machines, it is not unidirectional and uniform in sense like transformer. So the reluctance offered in one direction will reduce and other direction might increase and this will create a harmful imbalance.
If you are interested, search for amorphous core transformers that are still superior compared to these.
Thank you for your time and please feel free to leave comments about your areas of interest. I will surely try to post about them.
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