OPEN CIRCUIT AND FULL LOAD CURRENT – Open circuit test is carried out for measuring iron losses and full load current test is carried out for determining for total losses including iron loss.3 phase 440 volt 200 amp variac gives supply to booster transformer. Tapping of booster transformer is taken 1100 volt ,2200 volt and 3300 volt .Between variac of 200 amp and booster transformer capacitor bank of maximum 200 KVAr is inserted in the binary arrangement  to maintain stability of supply and  improving of power factor. Tapping of booster transformer is changed manually according to need i.e. for testing of transformer 11kv/0.43kv , 22kv/11kv and 33kv/11kv.

DOUBLE VOLTAGE DOUBLE FREQUENCY TEST – This test is carried out for checking insulation sustainability of transformer as it must sustain on applying double voltage . There is no other purpose for doubling the frequency but to ensure that iron looses should not increase abnormally. If voltage is doubled and frequency is kept same iron looses will be abnormally high causes heating of core of transformer. This set consisting of 20HP squirrel cage induction motor. Which is used as prime mover and operated through star delta starter.Generator is specially designed for 3-phase ac winding either stator or rotor is used as primary/secondary. This is wound type stator and rotor. Separate supply is given to primary through 440 volt 50 amp at 50 hz variac .output of generator is applied on transformer under test. Primary poles of secondary is double then primary .Transformer under test having open. Secondary voltage impressed on transformer first it is increased to 1/3 rating then full voltage rating for 60 sec. period. Dimmer is controlled through panel. Rating of DVDF is 50kva.

HV test (high voltage test ) – This test is carried out on transformer for high voltage specified by BIS (Bureau of Indian Standards) OR IEC(International Electrotechnical Commission) .HV transformer voltage is increased through taking out supply from 2-phases of dimmer .This dimmer is motor operated and control through panel. Rating of HV transformer is 80kv , 200mA.dimmer rating is 440volt 50amp.