Q.1
How many types of cooling methods are available for the transformer?
  • a) 3
  • b) 2
  • c) 1
  • d) 4
Q.2
How are the radiators cooled in the present time?
  • a) by natural cooling
  • b) by forced cooling using small fans
  • c) by forced cooling using large fans
  • d) by using external air
Q.3
What type of cooling is being made use of in transformers having a capacity of less than 11MVA?
  • a) natural cooling
  • b) forced cooling
  • c) air blast cooling
  • d) forced cooling and air blast cooling
Q.4
Compared to the natural cooling, how much of heat dissipation is increased by air blast cooling?
  • a) 50-70%
  • b) 60-70%
  • c) 50-60%
  • d) 40-60%
Q.5
Increase in the velocity of oil circulation increases the transformer output.
  • a) true
  • b) false
Q.6
What is the relation of the increase of the oil circulation rate with energy losses?
  • a) increase of the oil circulation rate is not depending with energy losses
  • b) increase of the oil circulation rate is directly proportional to the energy losses
  • c) increase of the oil circulation rate is directly proportional to the square of energy losses
  • d) increase of the oil circulation rate is indirectly proportional to energy losses
Q.7
What is the flow rate of the circulating oil in an air cooler with natural air cooling?
  • a) 12.5 litre per minute per KW of losses
  • b) 12 litre per minute per KW of losses
  • c) 14 litre per minute per KW of losses
  • d) 13 litre per minute per KW of losses
Q.8
What is the range of the cooler surfaces per 1 KW of losses?
  • a) 0.1-0.25 m2
  • b) 0.18-0.2 m2
  • c) 0.1-0.2 m2
  • d) 0.18-0.25 m2
Q.9
What is the range of the flow rate of circulating oil per KW of losses?
  • a) 6-7 liters per minute
  • b) 5-6 liters per minute
  • c) 6-8 liters per minute
  • d) 6-7 liters per minute
Q.10
The temperature difference between the incoming and outgoing water is greater than 10°C.
  • a) true
  • b) false
Q.11
What is the formula for width of the tank for single phase transformers used?
  • a) width of tank = 2*distance between adjacent limbs + external diameter of h.v windings + 2*clearance between h.v windings and tank
  • b) width of tank = distance between adjacent limbs + external diameter of h.v windings + 2*clearance between h.v windings and tank
  • c) width of tank = 2*distance between adjacent limbs * external diameter of h.v windings + 2*clearance between h.v windings and tank
  • d) width of tank = distance between adjacent limbs * external diameter of h.v windings + 2*clearance between h.v windings and tank
Q.12
What is the formula for the length of the tank?
  • a) length of the tank = external diameter of h.v winding + clearance on each side between the winding and tank along the width
  • b) length of the tank = external diameter of h.v winding * clearance on each side between the winding and tank along the width
  • c) length of the tank = external diameter of h.v winding + 2*clearance on each side between the winding and tank along the width
  • d) length of the tank = external diameter of h.v winding / 2*clearance on each side between the winding and tank along the width
Q.13
What is the formula for the height of transformer tank?
  • a) height of transformer tank = Height of transformer frame + clearance height between the assembled transformer and tank
  • b) height of transformer tank = Height of transformer frame * clearance height between the assembled transformer and tank
  • c) height of transformer tank = Height of transformer frame/clearance height between the assembled transformer and tank
  • d) height of transformer tank = Height of transformer frame – clearance height between the assembled transformer and tank
Q.14
What is the rating of the transformer for the voltage of aboutkV?
  • a) 1000-2000 kVA
  • b) 100-3000 kVA
  • c) 1000-5000 kVA
  • d) 100-500 kVA
Q.15
What is the rating of the transformer for the voltage of abovekV uptokV?
  • a) 1000-5000 kVA
  • b) less than 1000 kVA
  • c) above 1000 kVA
  • d) 100-500 kVA
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