SEI makes transformers with input and output voltage upto 3.3 KV single phase or 3 phase upto 200 KVA capacity suitable for 50 / 60 Hz supply. Low voltage transformers are also made suitable for other frequencies such as 400 Hz, SEI also makes special types of electronic low voltage transformers such as 3 phase to 2 phase transformers (Scot connected transformers) & 3 3 phase to 1 Phase transformer, within above voltage and power limits. These low voltage transformers are available in different thermal classes A, B, F, H & C.SEI Transformers confirm to IS 2026, IS11171, BS 171. Transformers are also made to confirm other national and intrnational standards against specific requirments. Electronic low voltage transformers are supplied either in open execution for incorporating in user panel or in sheet metal enclosures which are mostly for indoor application. For outdoor duty transformers are supplied in oil cooled construction. Oil cooled transformers are also prefered for heavy duty individual applications.