Power Transformers: Special Transformers from converter, furnace or rectifier transformers we can customize for special applications as well.
Converter Transformers
These Transformers are used to supply variable speed drives (VSD) for motor control. A VSD typically injests a whole spectrum of harmonics into the supply lines, and the transformers design needs to accommodate these harmonics. A convertor transformer is typically rated at 100% capacity, when a Distribution transformer is typically rated at 80% capacity. VSD drives are based on power electronic and usually require a neutral line, hence the most common vector group is DYn11, i.e. a Delta Primary with a star Secondary with the neutral point brought out.
Furnace Transformers
The smeltering Industry uses AC & DC processes depending on the Arc Furnace application. DC Electric Arc Furnace (EAF) Transformers are similar in design to rectifier transformers, but have many more taps and on-load tap-changers. AC (EAF) transformers are subjected repeat short circuit conditions that require a more conservative design. They too have many taps and on-load tap changers. The AC (EAF) Transformers are generally manufactured as single phase units which allow the furnace design and process to be optimised.
Rectifiers Transformers
These transformers cover a large range of configurations. The IEC60076 standards lists 19 configurations, most of the configurations were developed in the era of Mercury-arc rectifiers and have less relevance since the development of high current thyristors (silicon controlled rectifiers) and more advanced devices such as GTOs & IGCTs. The two commonly used rectifiers are the three phase bridge rectifier and the 6 phase double star with inter-phase transformer (IPT) which requires a dual secondary winding transformer design. The normal bridge rectifier uses a normal 3 phase design. We offer extended delta, phase shifted transformers where impedance and voltage matching is critical in a twelve pulse plant.
Special Application Transformers
Transformers supplying dedicated or non – distribution type loads are designed to customer specific requirements.
A large range of specialized application transformers can be designed and manufactured.
Some of the more frequent applications are, transformers supplying 6 pulse and 12 pulse rectifier circuits, Earthing transformers with auxiliary voltage supply, Isolation transformers , Auto – wound transformers with either primary or secondary voltage variation, Neutral Earthing resistors and many more.
