Constructional details of transformer - MCQs with Answers

Constructional details of transformer - MCQs with Answers

Q1. In a 5 kV / 400V, 75 kVA single phase transformer, the current flowing in the primary winding of transformer is 10A. what will be the current flowing in the secondary winding?

a. 100A
b. 120A
c. 125A
d. 130A

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Q2. The hysteresis loss in a transformer is minimized by using

a. Laminated sheets of steel
b. Special grade of heat treated grain oriented silicon steel
c. Bracing of transformer assemblies
d. Proper design of winding

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Q3. Laminations and varnish are used to reduce the eddy current losses. The laminations and varnish tends to present a

a. High resistance path to eddy current
b. Low resistance path to eddy current
c. Low reluctance magnetic path
d. High reluctance magnetic path

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Q4. In a transformer sludging is principally due to

a. Moisture present in oil
b. Dust particles present inside the tank
c. Decomposition of oil
d. Vaporization of oil

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Q5. Breather present in a transformer is used to

a. Absorb atmospheric moisture
b. Prevent insulation failure
c. Cooling
d. All of these

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Q6. The globules of water present in oil may result directly in a breakdown. This can be prevented by

a. Proper insulation
b. Isolation of oil from air by using an inert gas
c. Heating the tank
d. None of these

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Q7. In a transformer tank, grounding is given to protect it from lightening stoke. Grounding lug is usually installed near

a. bottom of the tank
b. Top of the tank
c. In the middle of the tank
d. Anywhere on the tank

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