Multilayer helical windings are commonly used in the transformers as high voltage windings

Helical windings are used in

A

distribution transformers

B

power transformers

C

shell type transformers

D

none of the above

Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in

A

short-circuiting of the secondaries

B

power factor of one of the transformers is leading while that of the other lagging

C

transformers having higher copper losses will have negligible core losses

D

loading of the transformers not in proportion to their kVA ratings

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is

A

1 + 0.2 kV mm

B

2 + 0.5 kV mm

C

4 + 0.7 kV mm

D

5 + 0.9 kV mm

Cylindrical windings using circular conductors, employed in transformers, are

A

single layered

B

double layered

C

multi-layered

D

none of the above

The insulation between windings and grounded core and the insulation between the windings of the same phase is

A

minor insulation

B

major insulation

C

either of the above

D

none of the above

Why transformers connected in parallel should have same voltage ratio?

A

To avoid full load circulating current

B

To avoid no-load circulating current

C

To avoid other losses

D

To avoid all type of currents

The material commonly used for insulation in high voltage cables is

A

Lead

B

Paper

C

Rubber

D

None of the above

A helical antenna is used for satellite tracking because of

A

Circular polarization

B

Maneuverability

C

Beamwidth

D

Gain

The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that

A

It is subjected to a higher cyclic loading than the outer side

B

It is subjected to a higher stress than the outer side

C

It is more stretched than the outer side during the manufacturing process

D

It has a lower curvature than the outer side

Helical coils can be used on

A

low voltage side of high kVA transformers

B

high frequency transformers

C

high voltage side of small capacity transformers

D

high voltage side of high kVA rating transformers

Multilayer helical windings are commonly used in the transformers as high voltage windings

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