Transformers

[amp_mcq option1=”high eddy current losses” option2=”reduced magnetic leakage” option3=”negligibly hysteresis losses” option4=”none of the above” correct=”option1″]

Detailed SolutionA shell-type transformer has

[amp_mcq option1=”nearly full load” option2=”70% full load” option3=”50% full load” option4=”no load” correct=”option1″]

Detailed SolutionPower transformers are designed to have maximum efficiency at

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

Detailed SolutionThe efficiency of a transformer will be maximum when

[amp_mcq option1=”llkV” option2=”33kV” option3=”66 kV” option4=”122 kV” correct=”option4″]

Detailed SolutionWhich of the following is not the standard voltage for power supply in India?

[amp_mcq option1=”core built-up of laminations of cold rolled grain oriented steel” option2=”core built-up of laminations of hot rolled sheet” option3=”either of the above” option4=”none of the above” correct=”option1″]

Detailed SolutionReduction in core losses and increase in permeability are obtained with transformer employing

[amp_mcq option1=”Increased core losses” option2=”Increased I2R losses” option3=”Magnetic interference with communication circuits” option4=”All of the above” correct=”option4″]

Detailed SolutionHarmonics in transformer result in

[amp_mcq option1=”unity” option2=”lagging” option3=”leading” option4=”zero” correct=”option1″]

Detailed SolutionMinimum voltage regulation occurs when the power factor of the load is

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

Detailed SolutionOpen circuit test on transformers is conducted to determine

[amp_mcq option1=”to project against internal fault” option2=”to reduce copper as well as core losses” option3=”to cool the transformer oil” option4=”to take care of the expansion and contraction of transformer oil due to variation of temper-ature of sur-roundings” correct=”option4″]

Detailed SolutionThe function of conservator in a transformer is

[amp_mcq option1=”The power factor of the two transformers will be different from the power factor of common load” option2=”Incorrect polarity will result in dead short circuit” option3=”The transformers will not share load in proportion to their kVA ratings” option4=”none of the above” correct=”option2″]

Detailed SolutionWhat will happen if the transformers working in parallel are not connected with regard to polarity?