For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?
Correct answer: C. 2.2 to 3.2 A/mm2
- A. 1.0 to 1.2 A/mm2
- B. 1.5 to 2.0 A/mm2
- C. 2.2 to 3.2 A/mm2
- D. 3.2 to 4.2 A/mm2
Explanation
Large transformers with oil cooling or air-blast cooling commonly use a conductor current density of about 2.2 to 3.2 A/mm². The permissible density is higher than in small or naturally cooled transformers because heat removal is more effective.
Last updated
Practise Electrical Machines
1,061 free Electrical Machines MCQs from Electrical Engineering, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Electrical Engineering questions like this
Electrical Engineering is on 2 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
5 H.P., 50-Hz, 3-phase, 440 V, induction motors are available for the following r.p.m. Which motor will be the costliest ?
A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?
A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be____________?
A 3-phase induction motor delta connected is carrying too heavy load and one of its fuses blows out. Then the motor______________?
A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor_______________?