With over millions of electrical transformers are serving different industries, somewhere some transformers are returning to transformer repairing and maintenance services providers for fault fixing. While there are variety of parts that complete the model, windings of transformers is most critical component.
The users of transformers can arrange different types of windings when required. Windings are the conductors installed in the shape of disc, helical, cylindrical, and crossover which creates mmf that is carried by the core to other installed windings to provide distinct level of voltages.
Transformer manufacturers are generally making two designs-
- Core type transformer
- Shell type transformer
In core type, manufacturers install and wrap the primary and secondary winding on the outer limbs. In shell type, primary and secondary windings are wrapped over the inner limbs.
Manufacturers apply concentric type winding to core transformers and place low voltage winding near to the core. They interlace the windings to reduce leakage reactance. Manufacturing company considers a list of factors to decide core windings, such as current rating, limit of temperature rise, short circuit withstand capacity, surge voltage, impedance, transport facilities, etc.
Types of windings applied by manufacturers in core type transformer
Cylindrical windings are designed in layers and use round or rectangular conductors. The conductors are wound over flat sides and on the rib side of the transformer.
Why Cylindrical Windings are used?
Cylindrical windings are low voltage windings that are installed in the transformers having current rating between 10 to 600A. Manufacturing units often apply these windings in its multi-layer design. They install rectangular conductors in two-layered type as it is handy to protect the lead-out ends. Oil ducts present in the device separate the windings layers and this arrangement initiates the cooling by circulating oil in the winding.
In multi-layer cylindrical windings, manufacturers use circular conductors on vertical strips to enhance cooling conditions. This arrangement helps oil ducts to provide better cooling.
There are three types of helical windings – single, double, and disc. Single helical windings are in an axial direction along a screw line. Manufacturers use only single layer turn in each winding. Double helical winding as double layers turns that reduce eddy current loss in conductors. Disc helical windings are parallel connected strips placed side by side by manufacturers in a radial direction to cover total radial winding depth.
Multi layer helical winding
Manufacturers usually install multi layer helical windings for high voltage ratings ranging from 110 kV and more. These windings have multiple cylindrical layers that are concentrically wound and interlinked in series.
Crossover windings are ideally used in small transformers. These types of windings have higher strength than cylindrical windings when used under normal condition.
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All these windings are applicable for core type transformers. Transformer repairing and maintenance services providers use and replace the faulty windings with suitable windings. The repairing cost is generally more but you have to perform transformer repair for better functioning of the unit.