What is the core loss of a transformer?

The core plays a crucial role in electrical equipment such as transformers and motors, and core loss is an important factor that affects the performance and efficiency of these devices. Understanding the composition of core loss and its influencing factors has far-reaching significance for the optimal design, efficient operation, and energy conservation of the equipment.

Content

● Hysteresis Loss

Hysteresis loss mainly stems from the material properties of silicon steel sheets. Different silicon steel sheets have different hysteresis loops, and the area enclosed by the hysteresis loop directly reflects the magnitude of the hysteresis loss. For high-quality silicon steel sheets, their hysteresis loops are relatively narrow, and thus the hysteresis loss is small. During the core processing, operations like bending and dropping can distort the lattice structure inside the silicon steel sheets, thereby changing their magnetic properties and resulting in an increase in hysteresis loss.

For example, when manufacturing the core of a transformer, if the silicon steel sheets are overly bent, the local magnetic domain arrangement will be disordered, increasing the hysteresis phenomenon and further raising the hysteresis loss, which will affect the overall efficiency of the transformer. Especially in application scenarios where the magnetic field direction changes frequently, such as the operation of power transformers in the power system, the impact of hysteresis loss on the energy conversion efficiency is more noticeable.

● Eddy Current Loss

Eddy current loss is closely related to the surface condition and thickness of the silicon steel sheets. When the burrs on the silicon steel sheets are large, the contact area between the sheets increases, making it easier for eddy currents to form loops, which leads to an increase in eddy current loss. Poor insulation between the sheets will also allow eddy currents to conduct between the silicon steel sheets instead of being effectively confined within a single sheet, also increasing the eddy current loss. Moreover, if the silicon steel sheets are too thick, larger circulating currents of eddy currents will form inside the silicon steel sheets. Because according to the formula for eddy current loss, it is proportional to the square of the thickness of the silicon steel sheets.

For example, in the core of a motor, if the used silicon steel sheets have serious burrs and their thickness exceeds the reasonable range, excessive heat will be generated due to eddy current loss during the motor's operation. This will not only reduce the motor's efficiency but may also affect the motor's insulation performance and service life due to overheating. In equipment operating at high frequencies, this impact is even more prominent.

● Core Additional Loss

The product structure has a significant impact on the core additional loss, such as the straight and oblique joint methods of the core. The straight joint structure is relatively simple, but it will cause relatively large changes in magnetic resistance at the joints, resulting in local magnetic field distortion and thus triggering additional losses. The oblique joint can improve the magnetic field distribution to a certain extent and reduce additional losses. The quality status of the silicon steel sheets during the processing is also crucial. If the processing precision is low and there are large dimensional deviations or the surface is uneven, the magnetic field distribution will be uneven after the core is assembled, increasing the additional losses.

In some transformers with special structures or electrical equipment with extremely high requirements for efficiency, optimizing the product structure and strictly controlling the processing quality of the silicon steel sheets are the key measures to reduce the core additional loss, which is directly related to the performance improvement and energy utilization efficiency of the equipment.

In Summary

The core loss is composed of hysteresis loss, eddy current loss, and core additional loss, and its magnitude is comprehensively affected by multiple factors such as the material of the silicon steel sheets, processing techniques, and product structure. A deep understanding of core loss helps in the design, manufacturing, and operation processes of electrical equipment to effectively reduce core loss through reasonable selection of silicon steel sheets, optimization of processing techniques, and improvement of product structure, thereby improving the overall performance and operation efficiency of the equipment and achieving energy-saving goals, meeting the needs of modern industry for efficient and reliable electrical equipment.

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LuShan, est.1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single-phase transformer,three-phase isolationtransformer,electrical transformer,distribution transformer, step down and step up transformer, low voltage transformer, high voltage transformer, control transformer, toroidal transformer, R-core transformer;DC inductors, AC reactors, filtering reactor, line and load reactor, chokes, filtering reactor, and intermediate,high-frequency products.

Our power transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering(furnace), central air conditioning.

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