In a shunt generator the voltage build up is generally restricted by

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

The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except

A

Armature reaction

B

Armature resistance drop

C

Field weakening due to armature reaction and armature

D

Commutation

If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

A

This will make armature to take heavy current, possibly burning it

B

This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

C

Nothing will happen to motor

D

Motor will come to stop

If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens

A

Nothing will happen to the motor

B

This will make armature to take heavy current, possibly burning it

C

This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

D

Motor will run at very slow speed

A cumulatively compounded long shunt generator when operating as a motor would be

A

Cumulatively compounded long shunt

B

Differentially compounded long shunt

C

Cumulatively compounded short shunt

D

Differentially compounded short shunt

A shunt generator can self-excite

A

Only if the resistance of the field circuit is less than critical value

B

Only if the resistance of the field circuit is greater than critical value

C

Irrespective of the value of the resistance in the field circuit

D

None of the above

The series field of a short-shunt D.C. generator is excited by

A

external current

B

armature current

C

shunt current

D

load current

The maximum number of steps in a flight should generally be restricted to

A

10

B

12

C

15

D

No limit

If the width of the foundation for two equal columns is restricted, the shape of the footing generally adopted, is

A

Square

B

Rectangular

C

Trapezoidal

D

Triangular

Natural air cooling is generally restricted for transformers up to

A

1.5 MVA

B

5 MVA

C

15 MVA

D

50 MVA

In a shunt generator the voltage build up is generally restricted by

Related Questions