In power systems, transformers are indispensable devices with the primary function of adjusting voltage levels to meet various electrical demands. The windings are a core component of transformers, directly influencing their electrical performance and operational efficiency. Among many winding structures, concentric windings are widely used due to their excellent electrical characteristics, mechanical stability, and thermal capabilities. This article provides a detailed overview of concentric windings and their major types.
Concentric windings refer to a structural design where the windings are arranged in concentric circles on any cross-section of the transformer’s core column. Typically, the high-voltage winding is placed on the outer side of the core column, while the low-voltage winding is positioned internally, closer tothe core. There must be a certain insulation gap between the high-voltage and low-voltage windings to ensure effective heat dissipation. The size of the insulation gap depends on the voltage level and heat dissipation requirements of the winding. When the low-voltage winding is close to the internal core column, due to its relatively small insulation distance with the core column, the overall transformer size can be effectively reduced.
Types of Concentric Windings
Concentric windings primarily include the following types:
I. Cylindrical Windings
Cylindrical windings are formed by stacking conductors and can be either single-layer or multi-layer. The design of these windings is relatively straightforward, making them suitable for low-power transformers, particularly in many household appliances and electronic devices.
The main advantage of cylindrical windings lies in their ability to resist mechanical stress, effectively preventing deformation due to rising temperatures or external impacts. This winding form typically involves tight winding, ensuring that there are no gaps between each winding turn, thus maximizing current conduction efficiency and minimizing energy loss. Moreover, the structure of cylindrical windings allows for optimal heat dissipation, enabling the equipment to maintain good operational conditions during prolonged use.
II. Helical Windings
Helical windings are specifically designed for large-capacity low-voltage transformers, making them particularly suitable for applications requiring operation under high loads. This structure ensures uniform current distribution through the parallel connection of multiple conductors, minimizing energy waste.
In helical windings, the arrangement of conductors and the design of cooling channels are especially critical for ensuring effective heat dissipation under high-load conditions. This winding form enhances the flow path for current, reducing the risk of localized overheating, and improves the overall reliability and safety of the transformer. Furthermore, helical windings exhibit significant advantages in terms of enhancing conductive performance and reducing resistance loss, making them widely applicable in power transformers and large electrical equipment.
III. Continuous Windings
Continuous windings are a common type of disc winding with unique structural features. In this design, the conductors are arranged in a longitudinal direction, forming various types of windings. The layout between the individual coils is meticulously planned to ensure effective cooling and thermal dissipation. Due to their high mechanical strength, continuous windings are particularly suitable for use in large transformers.
These windings are typically made from flat conductors, with the number of segments reaching between 30 and 100, employing specific manufacturing techniques (such as side winding). Because there are no solder joints between the windings, they are referred to as continuous windings. They are widely used in large transformers and can efficiently meet performance requirements for both low and high voltage windings.
Through this design, continuous windings significantly enhance cooling capabilities while also improving resistance to short-circuit conditions. This results in greater stability and reliability under high load operations, making continuous windings an essential component in modern electrical equipment, especially in applications where space optimization and electrical performance are critical.
