Copper, even though costly, finds use in the windings of electrical machines because

Is universally used for windings of electrical machines because it is easily workable without any possibility of

A

fracture

B

Silver

C

Steel

D

Aluminium

E

Copper

Even minute presence of impurities in copper impairs its electrical conductivity seriously. Electrolytic refinning of blister copper is resorted to, when

A

Cheap electricity is available

B

The precious metal content of copper is high

C

There is a demand for ultrapure (99.99%) electrolytic copper

D

All of the above

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

A

upto 20 kV

B

upto 50 kV

C

upto 80 kV

D

for 110 kV and 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

If 2 kg of metal, of which 1/3 is zine and the rest is copper , be mixed with 3 kg of metal, of which 1/4 is zinc and the rest is copper , then what will be the ratio of zinc to copper in the mixture?

A

17 : 43

B

13 : 42

C

19 : 43

D

15 : 42

If 2 kg of metal, of which 1/3 is zinc and the rest is copper s, be mixed with 3 kg of metal , of which 1/4 is zinc and the rest is copper , then what will be the ratio of zinc to copper in the mixture?

A

13 : 42

B

19 : 43

C

15 : 42

D

17 : 43

The weight of copper of both armature and field windings decreases with _____ in number of poles.

A

increase

B

decrease

C

either of the above

D

none of the above

The synchronous modems are more costly than the asynchronous modems because

A

they produce large volume of data

B

they contain clock recovery circuits

C

they transmit the data with stop and start bits.

D

they operate with a larger bandwidth

E

None of the above

Silicon steel is used in electrical machines because it has

A

Low coercivity

B

Low retentivity

C

Low hysteresis loss

D

High coercivity

Which of the following alloy steels has the energy saving properties making it suitable for use in electrical machines?

A

Silicon steel

B

Chromium steel

C

Molybdenum steel

D

None of these

Copper, even though costly, finds use in the windings of electrical machines because

Related Questions