When winding a transformer, what should be considered?

a. During the winding process, special attention must be paid to the winding direction; otherwise, it may result in an incomplete magnetic circuit within the iron core. Winding directions for small to medium-sized three-phase transformers are generally the same. However, for single-phase transformers with two-column windings, especially for single-phase three-split windings with three iron core columns, the winding direction of the middle column is opposite to that of the two side columns.

b. It is crucial to avoid any offset during the winding process; otherwise, it may lead to the following consequences: after the winding offset, the distance between windings decreases on one side and increases on the other side. Furthermore, offsetting the outer winding may also cause a reduction or increase in the distance between phases, affecting the distance of the main insulation. After winding offset, the repulsive forces F₁ and F₂ on both sides of the winding are unequal. In concentrically arranged windings, a force tends to bring them towards concentricity, while in interleaved windings, different concentricities continue to increase, further affecting the distance between the winding and the iron core. However, winding offset does not affect the impedance voltage, as the impedance voltage is related to the area between the two windings. Winding offset does not alter this area, thus maintaining the impedance voltage unchanged.

c. Symmetry in the vertical direction is necessary during the winding process. According to insulation requirements, the high-voltage winding has a higher ground voltage and a greater distance, so the high-voltage winding is generally slightly shorter than the low-voltage winding. Due to manufacturing tolerances in windings, there are also tolerances in the heights of high and low-voltage windings. However, during the winding process, it is essential to ensure that the geometric dimensions of the high and low-voltage windings are aligned at the center; otherwise, axial electromagnetic forces may increase, leading to a further expansion of the height difference (refer to question 30).

d. When winding on a transformer core with glass tape binding, it is necessary to pre-tighten and bind the upper end of the core with clamps and straps to prevent the upper core piece from tilting to both sides and causing tape bulging.

It should be emphasized that during the winding process, it is preferable to preassemble the windings together and then wrap the entire assembly on the transformer core column. This approach can accelerate the assembly speed and reduce the risk of moisture absorption.

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 transformers, DC inductors, AC reactors, filtering reactor, expoxy resin high-voltage transformer and intermediate, high-frequency products. Our 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, central air conditioning.

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