Transformers

[amp_mcq option1=”tightness of clamping” option2=”gauge of laminations” option3=”size of laminations” option4=”all of the above” correct=”option4″]

Detailed SolutionThe degree of mechanical vibrations produced by the laminations of a transformer depends on

[amp_mcq option1=”$$\frac{{{{\text{R}}_2}}}{{\sqrt {\text{K}} }}$$” option2=”$$\frac{{{{\text{R}}_2}}}{{{{\text{K}}^2}}}$$” option3=”$$\frac{{{\text{R}}_2^2}}{{{{\text{K}}^2}}}$$” option4=”$$\frac{{{\text{R}}_2^2}}{{\text{K}}}$$” correct=”option3″]

Detailed SolutionIf R2 is the resistance of secondary winding of the transformer and K is the transformation ratio then the equivalent secondary resistance referred to primary will be

[amp_mcq option1=”primary side” option2=”secondary side” option3=”low voltage side” option4=”high voltage side” correct=”option2″]

Detailed SolutionIn a transformer the tappings are generally provided on

[amp_mcq option1=”to provide oxygen inside the tank” option2=”to cool the coils during reduced load” option3=”to cool the transformer oil” option4=”to arrest flow of moisture when outside air enters the transformer” correct=”option4″]

Detailed SolutionThe function of breather in a transformer is

[amp_mcq option1=”90% load” option2=”Zero load” option3=”25% load” option4=”50% load” correct=”option4″]

Detailed SolutionDistribution transformers are generally designed for maximum efficiency around

[amp_mcq option1=”1.7 Wb/m2″ option2=”2.7 Wb/m2″ option3=”3.7 Wb/m2″ option4=”4.7 Wb/m2″ correct=”option1″]

Detailed SolutionThe permissible flux density in case of cold rolled grain oriented steel is around

[amp_mcq option1=”fluctuating load” option2=”poor insulation” option3=”mechanical vibrations” option4=”saturation of core” correct=”option4″]

Detailed SolutionThe main reason for generation of harmonics in a transformer could be

[amp_mcq option1=”load on it increases” option2=”load on it decreases” option3=”load remains constant” option4=”none of the above” correct=”option1″]

Detailed SolutionTransformer breaths in when

[amp_mcq option1=”Magnetostriction” option2=”Boo” option3=”Hum” option4=”Zoom” correct=”option1″]

Detailed SolutionThe noise resulting from vibrations of laminations set by magnetic forces, is termed as

[amp_mcq option1=”wood” option2=”copper” option3=”aluminium” option4=”silicon steel” correct=”option4″]

Detailed SolutionMaterial used for construction of transformer core is usually