Et Imp Questions 2015-16

8/19/2019 Et Imp Questions 2015-16

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Assignment Questions for B.E II/I YEAR/SEM E.C.E

ELECTRICAL TECHNOLOGYUNITI

1. Write the principle of operation of D.C Generator?

2. What do you understand by commutation in DC machines?3. Draw the torque-speed characteristic of DC shunt and series motor?

. What do you understand by armature reaction?!. Write the equation for the torque de"eloped in DC #otor?$. #ention "arious methods of e%citation of DC #achine?

&. 'a( Deri"e the torque equation of a DC motor.

'b( )he armature of a $-pole DC *enerator has a wa"e windin* containin*$$ conductors.Calculate the *enerated emf when flu% per pole is +.+$ weber and speed is 2!+ rpm. ,t

what speed must the armature be dri"en to *enerator on emf of 2!+ if the flu% per pole

is reduced to +.+! Weber.. /%plain about 3-point starter in DC motor with neat dia*ram?

0. a( /%plain the process of commutation in a DC Generator

1+. Describe with neat setch the construction of a DC #achine?

1+. Discuss "arious methods of speed control applicable to series motor and hunt motor?11. arious power sta*es in dc motor and deri"e the condition for ma%imum efficiency?

UNITII

1. )he readin*s of two watt meters of 3-phase power measurement are !+ W and 1++ W

respecti"ely. Calculate power factor.2. Define synchronous impedance of an alternator.

3. Define re*ulation of ,C Generator?

. Gi"e the relationship between line quantities of "olta*e and current for a delta connected 3-

phase system?!. What do you understand by 3-phase balanced loads?$. Define "olta*e re*ulation of an ,lternator?

&. 'a( Draw tar-Delta connections of a 3-phase system and deri"e line and phase "olta*e for

both star and Delta connections.'b( Determine "olta*e re*ulation by the synchronous impedance method.

. , balanced star connected load of '-( 45phase is connected to a 3-67 ++7 !+89 supply.

:ind the line current7 power factor and power.0. a( /%plain power measurement by two wattmeter method.

b( /%plain armature reaction in alternator with neat dia*rams?

1+. , delta-connected balanced 3-phase load is supplied from a 3-phase7 ++ supply. )he line

current is 2+, and the power taen by the load is 1+;w find i(


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ELECTRICAL TECHNOLOGY1. Define synchronous impedance of an alternator

2. Deri"e the /.#.: /quation of alternator?3. /%plain the armature reaction of alternator for different load powerfactors?

. , 3-phase star connected alternator is rated at 1$++ ;,7 13+++ .)he armature resistance

and synchronous reactance are 1.!> and 3+> especti"ely per phase. Calculate percenta*e

"olta*e re*ulation for a load of 12+ ;W at power factor of +. la**in*.!. Define "olta*e re*ulation of an alternator?

$. /%plain synchronous impedance method for calculatin* re*ulation of alternator?

&. Determine "olta*e re*ulation by the synchronous impedance method.

UNITI!

1. a( #ention the application of auto-transformer. b(Define re*ulation and efficiency of transformer

2. Define efficiency and re*ulation of transformer.3. What are the "arious losses in transformer?. /%plain the importance of @C and C tests in transformers.

!. Define transformation ratio of transformer.

$. Draw the phasor dia*ram of a transformer for an


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ELECTRICAL TECHNOLOGY". /%plain why sin*le-phase induction motors are not self startin*.

#. Write short notes on )orque-lip characteristics of an induction motor with neat *raph?. Write the applications of shaded pole motors?

!. ,n -pole !+897 3-=hase induction motor has a rotor emf frequency of 289.Calculate slip

and speed.

$. /%plain how production of rotatin* ma*netic field produced in case of 3-=hase induction

motors.

&. 'a( /%plain the principle of rotatin* ma*netic field and hence pro"e it is of constant ma*nitude and rotates at synchronous speed.

'b( What is slip in 3-phase induction motor?

. Deri"e the torque-slip equation for a 3-phase induction motor and also the equation for slip at

which ma%imum torque occurs.0. With a neat dia*ram e%plain the construction and principle of operation of 3-=h

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Et Imp Questions 2015-16