What Is a Transformer Core and Why Is It Important?
Transformer core is the key component inside the transformer for guiding the magnetic field and realizing the closure of the magnetic circuit, which is responsible for efficiently transferring the magnetic flux from the primary side coil to the secondary side coil, completing the voltage conversion and transmission of electric energy.
Core function of the iron core
Constructing a low resistance magnetic circuit: Providing an optimal path for the magnetic field, reducing magnetic leakage and energy waste.
Ensure efficient voltage conversion: Directly affect the voltage conversion accuracy and transmission efficiency.
Controlling loss and temperature rise: Determining the level of heat generation, insulation life and overall reliability of the transformer.
What Are Laminated Sheets
Iron core stacked piece, is the ultra-thin cold-rolled oriented silicon steel sheet according to certain specifications after cutting, the piece of insulation between the superposition of the magnetic circuit structure, rather than the whole piece of solid steel.
Key difference between laminated core and solid core
Solid iron core: Whole piece of metal, eddy current path is complete, high loss, serious heat.
Stacked iron core: Thin slices are stacked on top of each other + insulation between the slices, cutting off the eddy current path and significantly reducing losses and heat generation while maintaining strong magnetic conductivity.
laminated structure achieves the optimal balance of loss and heat dissipation without sacrificing the performance of the magnetic circuit.
Main Reason: Reducing Eddy Current Losses
What are eddy currents?
When alternating current passes through a coil, it generates an alternating magnetic field, which induces a closed loop current, known as an eddy current, inside the solid iron core.
Three major hazards of eddy currents
Electrical energy is converted into heat, resulting in a large amount of wasted energy.
Temperature of the iron core rises, accelerating the aging of the insulation, shortening the life of the transformer.
Reduce the efficiency of the whole machine, increase the operating cost.
How to inhibit eddy current?
Stacked sheet structure cuts off the large loop of eddy current through the insulation between the sheets, restricting the eddy current to a very thin single sheet, significantly reducing the eddy current area and current intensity, thus significantly reducing the loss and heat generation. This is the most fundamental reason why transformers use laminated cores.
Additional Benefits of Laminated Transformer Cores
Comprehensively improve transformer efficiency
Stacked sheets provide low-resistance paths for magnetic flux, reducing hysteresis loss; at the same time, by dividing the conductive paths and reducing the size of the loop, eddy current loss is further reduced, thus realizing the optimization of energy conversion.
Improved Reliability and Service Life
Reduces core temperature rise and prevents premature insulation failure.
Reduces vibration and noise for quieter and more stable operation.
Optimize magnetic flux distribution and reduce the risk of magnetic saturation to ensure long-term safe operation.
Stabilized operation
Stabilized operating condition More uniform flux distribution, avoiding local saturation, suitable for long-term continuous load operation.
Why Lamination Thickness and Material Matter
Stack thickness is not as thin as possible, but rather a balanced choice between performance and engineering practicality.
Scenarios for different thicknesses
Thin type (0.23mm, 0.27mm) : Eddy current suppression effect is the best, applicable to high-frequency scenarios, high energy-efficiency special transformers.
Thick type (0.30mm, 0.35mm): High mechanical strength, high stacking coefficient, mostly used for large power transformers.
Industry Trends
In order to meet Tier 2, Tier 3 and other higher energy-efficiency standards, the industry is upgrading to thinner, higher-grade CRGO laminations to achieve lower overall losses.
Core of transformer adopts laminated structure, the core purpose is to inhibit eddy current loss, improve efficiency, reduce temperature rise, and then extend the service life, reduce noise, and ensure the stability of operation. The thickness and material selection of laminated iron core directly affects the energy efficiency of transformer and application scenarios.
Stacked iron core is the basic design of modern energy efficient transformers, but also an important guarantee of low-carbon and stable operation of the power system.
