Design of Electrical Machines Mock Test 3

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Question 1 of 10

1. What is the range of the permissible peripheral speeds in the 3 phase induction machine?

60-70 m per s

40-70 m per s

50-70 m per s

60-75 m per s

Question 1 of 10

Question 2 of 10

2. How are the radiators cooled in the present time?

by using external air

by forced cooling using small fans

by natural cooling

by forced cooling using large fans

Question 2 of 10

Question 3 of 10

3. What is the rating of the transformer for the voltage of above 11 kV upto 33 kV?

above 1000 kVA

100-500 kVA

less than 1000 kVA

1000-5000 kVA

Question 3 of 10

Question 4 of 10

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

50-60 mm

70-80 mm

60-70 mm

50-70 mm

Question 4 of 10

Question 5 of 10

5. What is the range for the current density at HT side for a distribution transformer?

2-2.5 Amp per mm²

2.4-3.5 Amp per mm²

2-3.5 Amp per mm²

1-3.5 Amp per mm²

Question 5 of 10

Question 6 of 10

6. What is the formula for the calculation of rotor resistance?

rotor resistance = resistance of the bars / resistance of end rings

rotor resistance = resistance of the bars + resistance of end rings

rotor resistance = resistance of the bars * resistance of end rings

rotor resistance = resistance of the bars - resistance of end rings

Question 6 of 10

Question 7 of 10

7. The rotor voltage on open circuit between slip rings should not exceed 500 V for small machines.

false

true

Question 7 of 10

Question 8 of 10

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

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

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

Question 8 of 10

Question 9 of 10

9. What is the relationship between current density, conductor area and resistance?

higher the current density, lower the conductor area, higher the resistance

lower the current density, lower the conductor area, lower the resistance

higher the current density, higher the conductor area, lower the resistance

higher the current density, higher the conductor area, higher the resistance

Question 9 of 10

Question 10 of 10

10. What is the formula for height of the single phase core type transformer?

height = height of the window + height of the yoke

height = height of the window – (2*height of the yoke)

height = height of the window – height of the yoke

height = height of the window + (2*height of the yoke)

Question 10 of 10