H. T. Transformer at Industrial Electrical Corporation. The works of M/s. IEC Transformers, are equipped to manufacture Distribution transformers for ratings upto 1500 KVA and nominal system voltage upto 11/33/66 KV. Our transformers are in service all over the country. To meet the ever growing demand we are updating our manufacturing programme to increase our range of manufacture to completely self protected (CSP); dry type transformers; Fail Safe transformers etc. as per the requirements of various Electricity Boards and private customers.

The transformers are usually oil immersed, natural cooled or dry type resin cast and suitable for indoor or outdoor installation. The transformers can be supplied either with Bare Bushings or Cable Boxed as per Customer's requirement. The manufacturing and testing at various stages strictly conforms to IS : 2026/1977. All fittings required are provided to suit customer's specific requirement.

The magnetic circuit is of a laminated iron core. The company uses laminations of special silicon sheet which gives a high resistivity (to reduce eddy current losses) and also a low hysteresis loos. Hot rolled or cold rolled grain oriented silicon steel is used for laminations.but cold rolled grain oriented steel laminations are used for cores in all IEC Transformers.

The LV windings are made form Paper covered Copper Strips and placed nearest to the core. The HV windings are would with Super Enamelled Copper Wire or Alluminium Wire or Paper covered Round wire or paper convered Strips depending upto the rating of the transformers. The cross section of the conductor is also chosen to keep the thermal gradient in the winding to a minimum and thus increase the life of transformer.

IEC are providing off load / on load tap changer for the voltage in a supply network can be controlled by changing the ratio of transformation This can be done by tapping the winding in order to alert the number of turns. The tap changer is provided on the high voltage winding because a fine voltage variation is obtained owing to large number of turns.

The transformers are fitted with Bare Porelain Bushings and metal parts conforming to IS specification 3347 Dimension for Porcelain transformer Bushing. All characteristics of the bushings conform to IS 2099 Specification for High Voltage Porcelain Bushing:. Alternatively transformer are supplied, fitted with Cable Box either with Wiping type of glands suitable for paper insulated cable or compression glands suitable for PVC/XLP cables.

The tanks are fabricated from MS plates and is welded construction. They are tasted at a pressuer of 0.35 Kg. /Sq. cm. For oil leakage at joints. The tanks are provided with number of pressed radiators to dissipate the conductors and core losses and they are normally welded directly to the tank. However, transformers, can be supplied with detachable radiators. The oil used for transformers to IS Specification 335-1984. New insulating oils for transformers and switchgears. Dry type Transformer fabricated from MS sheet with angle structure and with Ventilation.

The inside of the transformer tank and frame parts are given a coating of hot transformer oil resisting paint. The transformer is given an external anti-corrosive primer coat and two finishing coats usually of admirally grey.