Which of the following loss in a D.C. generator varies significantly with the load current?

The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator?

A

Hysteresis loss

B

Field copper loss

C

Armature copper loss

D

Eddy current loss

Which of the following losses are significantly reduced by laminating the core of a D.C. generator?

A

Hysteresis losses

B

Eddy current losses

C

Copper losses

D

Windage losses

Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator?

A

Dummy coils

B

Commutator

C

Eye bolt

D

Equalizer rings

When the axis of load lies in the plane of rivet group, then the most heavily loaded rivet will be the one which (where, Fa is the load shared by each rivet due to axial load and Fm is the shearing load due to moment in any rivet.)

A

Is at the maximum distance from CG of the rivet group

B

Is at the minimum distance from CG of the rivet group

C

Gives the maximum angle between the two forces Fa and Fm

D

Gives the minimum angle between the two forces Fa and Fm

In testing a pile by load test, pile platform is loaded with one and half times the design load and a maximum settlement is noted. The load is gradually removed and the consequent rebound is measured. For a safe pile, the net settlement (i.e. total settlement minus rebound) per tonne of test load should not exceed

A

10 mm

B

15 mm

C

20 mm

D

25 mm

In a synchronous motor which loss varies with load ?

A

Windage loss

B

Bearing friction loss

C

Copper loss

D

Core loss

A load which is spread over a beam in such a manner that it varies uniformly over the whole length of abeam is called uniformly ________ load.

A

Distributed

B

Varying

C

Both A and B

D

None of these

If A varies directly proportional to C and B also varies directly proportional to C, which one of the following is not correct ?

A

$$\left( {A + B} \right)\alpha \,C$$

B

$$\left( {A - B} \right)\alpha \,\frac{1}{C}$$

C

$$\sqrt {AB} \,\alpha \,C$$

D

$$\frac{A}{B} = {\text{constant}}$$

The e.m.f. generated by a shunt wound D.C. generator is E. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be

A

$$\frac{{\text{E}}}{2}$$

B

2E

C

Slightly less than E

D

E

A separately excited generator as compared to a self-excited generator

A

Is amenable to better voltage control

B

Is more stable

C

Has exciting current independent of load current

D

Has all above features

Which of the following loss in a D.C. generator varies significantly with the load current?

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