The transformer oil should have _______ volatility and _______ viscosity?

Related Mcqs:

1. The changes in volume of transformer cooling oil due to variation of atmospheric temperature during day and night is taken care of by which part of transformer?

   A. Conservator
   B. Breather
   C. Bushings
   D. Buchholz relay

2. Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds?

   A. 50°C
   B. 80°C
   C. 100°C
   D. 150°C

3. Which of the following is the main advantage of an auto-transformer over a two winding transformer?

   A. Hysteresis losses are reduced
   B. Saving in winding material
   C. Copper losses are negligible
   D. Eddy losses are totally eliminated

4. The dielectric strength of transformer oil is expected to be______________?

   A. lkV
   B. 33 kV
   C. 100 kV
   D. 330 kV

5. A transformer oil must be free from________________?

   A. sludge
   B. odour
   C. gases
   D. moisture

6. The no-load current drawn by transformer is usually what per cent of the full-load current ?

   A. 0.2 to 0.5 per cent
   B. 2 to 5 per cent
   C. 12 to 15 per cent
   D. 20 to 30 per cent

7. Efficiency of a power transformer is of the order of________________?

   A. 100 per cent
   B. 98 per cent
   C. 50 per cent
   D. 25 per cent

8. If R2 is the resistance of secondary winding of the transformer and K is the transformation ratio then the equivalent secondary resistance referred to primary will be___________?

   A. R2/VK
   B. R2IK2
   C. R22!K2
   D. R22/K

9. When a given transformer is run at its rated voltage but reduced frequency, its____________?

   A. flux density remains unaffected
   B. iron losses are reduced
   C. core flux density is reduced
   D. core flux density is increased

10. A Transformer transforms____________?

    A. voltage
    B. current
    C. current and voltage
    D. power