The winding is the most basic component of the transformer. Together with the core, it is called the power transformer body. It is the circuit part that establishes the magnetic field and transmits electrical energy. The power transformer winding consists of high-voltage winding, low-voltage winding, ground insulation layer (main insulation), insulation between high-voltage and low-voltage windings, oil channels composed of dovetail pads and stays, high-voltage leads, low-voltage leads, etc.
Power transformers with different capacities and voltage levels have different winding forms. Concentric and overlapping structures are commonly used in power transformers.
Concentric winding is to put high-voltage winding and low-voltage winding on the same iron core. Generally, the low-voltage winding is placed inside and the high-voltage winding is placed outside for insulation. However, for power transformers with large capacity and large output current, the process of low-voltage winding lead-out wire is complicated, and the low-voltage winding is often placed outside the high-voltage winding. Concentric winding has a simple structure and is easy to wind, so it is widely used. According to different winding methods, concentric winding can be divided into cylindrical, spiral, continuous, tangled and other types.
Overlap winding is also called staggered winding. On the same core, high-voltage winding and low-voltage winding are arranged alternately, with gap focus, complicated insulation and large packaging workload. Its advantages are good mechanical properties, convenient layout and welding of lead wires, and small leakage reactance. It is generally used in electric furnace transformers with voltages of 35KV and below.
The arrangement of the high and low voltage windings of the transformer is determined by many factors. But for most transformers, the low voltage winding is arranged inside the high voltage winding. This is mainly considered from the insulation aspect. Theoretically, no matter how the high voltage winding or the low voltage winding is arranged, it can play a role in voltage transformation. But because the iron core of the transformer is grounded, and because the low voltage winding is close to the iron core, it is easy to do from the insulation perspective. If the high voltage winding is close to the iron core, then because the voltage of the high voltage winding is very high, to meet the insulation requirements, a lot of insulation materials and a larger insulation distance are required. This not only increases the volume of the winding, but also wastes the insulation material. Furthermore, since the voltage regulation of the transformer is achieved by changing the tap of the high voltage winding, that is, changing its number of turns, it is easier to place the high voltage winding outside the low voltage winding.
Post time: Jul-25-2025
