If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then

When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected

A

the motor stops

B

it runs as a reluctance motor at the same speed

C

it runs as a reluctance motor at a lower speed

D

none of the above

A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will

A

remain same

B

go down

C

improve

D

none of the above

If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will

A

stop

B

run as induction motor

C

function as static condenser

D

burn with dense smoke

The Head of a newly formed government desires to appoint five of the six elected members A,B,C,D,E and F to portfolios of Home,Power,Defence ,Telecom and Finance.F dose not want any portfolio if D gets one the five.C wants either Home or Finance or on portfolio.B says that if D gets either Power or Telecom then she must get the other one.E insists on a portfolio if A gets one. If a gets Home and C gets Finance,then which is NOT a valid assignment for Defence and Telecom?

A

B-Defence,D-Telecom

B

B-Defence,E-Telecom

C

F-Defence,B-Telecom

D

D-Defence,B-Telecom

While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by

A

induction motor torque in field winding

B

induction motor torque in damper winding

C

eddy current and hysteresis torque in pole faces

D

reHetance motor torque due to saliency of the rotor

E

all of the above methods

The length of a rectangular field F is 3 km greater than the side of a square field M , and the width of field F is 3 km less then the side of field M. If the area of field M is m2 square km, what is the area of field F?

A

m2 +6

B

6

C

m2 - 6

D

m2 +9

A sum of TK. 53 is divided among A, B, C is such a way that A gets TK. 7 more than what B gets and B gets TK. 8 more than what C gets. The ratio of their shares is :

A

16:9:18

B

25:18:10

C

18:25:10

D

15:8:30

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

While starting a synchronous motor by induction motor action, field winding is usually

A

connected to D.C. supply

B

short-circuited by low resistance

C

kept open-circuited

D

none of the above

If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then

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