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Material commonly used in making transformer core is
cast iron
mild steel
high silicom steel
high carbon steel
high silicom steel
High silicon steel is the standard material used for transformer cores because it possesses high magnetic permeability and high electrical resistivity. The addition of silicon (typically 3-5%) reduces hysteresis loss and eddy current loss, significantly improving the transformer's efficiency.
High silicon steel is the standard material used for transformer cores because it possesses high magnetic permeability and high electrical resistivity. The addition of silicon (typically 3-5%) reduces hysteresis loss and eddy current loss, significantly improving the transformer's efficiency.
PhтАЛ=KhтАЛfBmax1.6тАЛ тАФ Steinmetz hysteresis loss formula
PeтАЛ=KeтАЛf2Bmax2тАЛt2 тАФ Eddy current loss formula
The core acts as a low-reluctance path for magnetic flux, which is generated by the primary winding. Silicon steel is used because its grain-oriented properties minimize energy dissipation during the rapid magnetic polarity reversals (hysteresis) and reduce circulating currents within the core (eddy currents). By increasing resistivity, the silicon content limits the magnitude of eddy currents, following the relation PeтАЛтИЭ╧Б1тАЛ, where ╧Б is the resistivity of the core material.
Silicon steel minimizes hysteresis loss by lowering the area of the B-H loop.
Lamination of the core reduces the effective path for eddy currents, further decreasing losses.
Grain-oriented silicon steel (CRGO) is preferred for high-efficiency transformers.
High resistivity of silicon steel reduces circulating current heating.
Lower power loss (high efficiency)
High magnetic permeability
Improved thermal stability
Increased material brittleness
Higher initial cost compared to mild steel
Power transformers
Distribution transformers
Electrical inductors
Cast iron has very high hysteresis loss and is unsuitable for transformer cores.
Mild steel has higher eddy current losses due to lower resistivity.
Silicon content is usually kept under 5% to prevent the material from becoming too brittle for manufacturing processes.
C is correct тАФ High silicon steel is the standard material used for transformer cores to minimize energy losses due to its high magnetic permeability and resistivity.
Always remember that in electrical machines, 'efficiency' is the primary driver for material selection; hence, minimize both Hysteresis (area of loop) and Eddy (resistivity) losses.