QUIZ4-EMD

What is the usage of the tanks with tubes?

• if the temperature rise with plain tank is very low

• if the temperature rise with plain tank is very high

• if the temperature rise is zero

• if the temperature rise with plain tank exceeds the specific limits

What is the relation of the provision of tubes with respect to dissipation of heat?

• the provision of tubes is directly proportional to the dissipation of heat

• the provision of tubes is indirectly proportional to the dissipation of heat

• the provision of tubes is directly proportional to square of the dissipation of heat

• the provision of tubes is indirectly proportional to square of the dissipation of heat

What is the relation of the transformer surface with respect to dissipation of heat?

• transformer surface has no relation with respect to dissipation of heat

• transformer surface has minor changes with respect to dissipation of heat

• transformer surface has major changes with respect to dissipation of heat

• transformer surface has no change with respect to dissipation of heat

How is the circulation of oil improved in tanks with tubes?

• it can be improved by using dissipating heat

• it can be improved by using more effective air circulation

• it can be improved by using more effect power flow

• it can be improved by using more effective heads of pressure

An addition of 35 percent should be made to tube area of the transformers.

• true

• false

What is the loss dissipated by tubes by convection, given area of the tubes = 3.5?

• 12.3 W per °c

• 2.51 W per °c

• 5.3 W per °c

• 30.8 W per °c

What is the formula for temperature rise with tubes?

• temperature rise with tubes = total loss / dissipating surface*(12.5 + 8.8x)

• temperature rise with tubes = total loss * dissipating surface*(12.5 + 8.8x)

• temperature rise with tubes = total loss / dissipating surface / (12.5 + 8.8x)

• temperature rise with tubes = total loss + dissipating surface*(12.5 + 8.8x)

What is the formula for number of tubes?

• number of tubes = (1/ 8 * area of each tube) * (total loss / temperature rise with tubes – 12.5 * dissipating surface)

• number of tubes = (1* 8 * area of each tube) * (total loss / temperature rise with tubes – 12.5 * dissipating surface)

• number of tubes = (1/ 8 * area of each tube) / (total loss / temperature rise with tubes – 12.5 * dissipating surface)

• number of tubes = (1/ 8 * area of each tube) + (total loss / temperature rise with tubes – 12.5 * dissipating surface)

What is the range of the diameter of the tubes used?

• 50-60 mm

• 60-70 mm

• 70-80 mm

• 50-70 mm

What is the formula for width of the tank for single phase transformers used?

• width of tank = 2*distance between adjacent limbs + external diameter of h.v windings + 2*clearance between h.v windings and tank

• width of tank = distance between adjacent limbs + external diameter of h.v windings + 2*clearance between h.v windings and tank

• width of tank = 2*distance between adjacent limbs * external diameter of h.v windings + 2*clearance between h.v windings and tank

• width of tank = distance between adjacent limbs * external diameter of h.v windings + 2*clearance between h.v windings and tank