Transformers Archives

31. When a given transformer is run at its rated voltage but reduced frequency, its

[amp_mcq option1=”flux density remains unaffected” option2=”iron losses are reduced” option3=”core flux density is reduced” option4=”core flux density is increased” correct=”option3″]

Detailed SolutionWhen a given transformer is run at its rated voltage but reduced frequency, its

32. Which of the following property is not necessarily desirable in the material for transformer core?

[amp_mcq option1=”Mechanical strength” option2=”Low hysteresis loss” option3=”High thermal conductivity” option4=”High permeability” correct=”option3″]

Detailed SolutionWhich of the following property is not necessarily desirable in the material for transformer core?

33. The ‘crawling’ in an induction motor is caused by

[amp_mcq option1=”high loads” option2=”low voltage supply” option3=”improper design of machine” option4=”harmonics developed in the motor” correct=”option2″]

Detailed SolutionThe ‘crawling’ in an induction motor is caused by

34. The term ‘cogging’ is associated with

[amp_mcq option1=”three phase transformers” option2=”compound generators” option3=”series motors” option4=”induction motors” correct=”option4″]

Detailed SolutionThe term ‘cogging’ is associated with

35. Short circuit test on transformers is conducted to determine

[amp_mcq option1=”hysteresis losses” option2=”copper losses” option3=”core losses” option4=”eddy current losses” correct=”option2″]

Detailed SolutionShort circuit test on transformers is conducted to determine

36. When the equivalent circuit diagram of doouble squirrelcage induction motor is constructed the two cages can be considered

[amp_mcq option1=”in series” option2=”in parallel” option3=”in series-parallel” option4=”in parallel with stator” correct=”option2″]

Detailed SolutionWhen the equivalent circuit diagram of doouble squirrelcage induction motor is constructed the two cages can be considered

37. An ideal transformer is one which has

[amp_mcq option1=”no losses and magnetic leakage” option2=”interleaved primary and secondary windings” option3=”a common core for its primary and secondary windings” option4=”core of stainless steel and winding of pure copper metal” correct=”option1″]

Detailed SolutionAn ideal transformer is one which has