Download Previous Year PTU University Question Paper of Synchronous Machines 5th Sem BTEE-501 B.Tech EE PTU Sept 2020 Paper
B.Tech. (EE-2011 Batch)
SYNCHRONOUS MACHINES
Subject Code : BTEE-501Â Â Â Â Â M.Code : 70554
Download Previous Year PTU University Question Paper of Asynchronous Machines 4th Sem BTEE-401 B.Tech EE PTU Nov 2018 Paper
Time : 2 Hrs.             Max. Marks : 30
INSTRUCTIONS TO CANDIDATES :
1. Attempt any FIVE question(s), each question carries 6 marks.
Synchronous Machines 5th Sem BTEE-501 B.Tech EE PTU Sept 2020 Paper
                   SECTION-A
1. Draw and explain equivalent circuit and phasor diagram of an alternator.
2. Derive pitch factor. Discuss the effect of harmonics on this factor. Also discuss the
necessity of chording the armature windings.
3. Explain two reaction theory of salient pole machines.                      4. Write a note on following :
a) Transient reactance of synchronous machines
b) Rating of Alternator is in kVA not in kW. Explain why.Â
5. Explain with the help a neat sketch the construction and working of Reluctance type Single
phase synchronous motor.
6. Discuss EMF method for calculating voltage regulation of an alternator.
7. What are the conditions of parallel operation of alternators? Also state advantages of the
parallel operation.
8. Explain why a three phase synchronous motor is not self starting. Describe two methods
used to start this motor.
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Explain equivalent circuit and phasor diagram of an alternator.
Pitch factor.
Discuss the effect of harmonics on this factor.
Discuss the necessity of chording the armature windings.
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Two reaction theory of salient pole machines.                     Â
a) Transient reactance of synchronous machines
b) Rating of Alternator is in kVA not in kW. Explain why.Â
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Construction and working of Reluctance type Single phase synchronous motor.
EMF method for calculating voltage regulation of an alternator.
Conditions of parallel operation of alternators? Also state advantages of the parallel operation.
Why a three phase synchronous motor is not self starting.
Describe two methods
used to start this motor.
Explain Why does a 3-phase induction motor always run at a speed less than the synchronous speed.
Asynchronous Machines 4th Sem BTEE-401 B.Tech EE PTU Nov 2018 Paper Click Here
3-phase induction motor crawls near half synchronous speed. Give the reasons.
3-phase cage rotor induction motor has a full load slip at 4%. The standstill current at rated voltage is 6.5 times full load current. Find auto transformer tapping to give full load torque at starting and also find line current at starting.
How the stationary, pulsating m.m.f. wave of a single phase induction motor can be considered as equivalent to two equal but oppositely rotating m.m.f. waves.
Constructional features and working of stepper motor.
Various methods of excitation of induction generator.
Asynchronous Machines 4th Sem BTEE-401 B.Tech EE PTU Nov 2018 Paper Click Here
1100 V, 50 Hz star connected induction motor has a star connected slip-rings rotor with a transformation ratio of 3.8 the rotor resistance per phase is 0.012 Ohm. and leakage inductance is 0.8 mH per phase. Neglect’ stator impedance.
(a) the rotor starting current per phase with slip rings short circuited,
The rotor power factor at starting
External resistance per phase to obtain a starting current of 100A in the stator.
The rotor current at 4% slip.
How the equivalent circuit of an ordinary polyphase induction motor is also applicable to deep-bar induction motors.
Working of universal motor and draw its phasor diagram.
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Time : 2 Hrs.             Max. Marks : 30
INSTRUCTIONS TO CANDIDATES :
1. Attempt any FIVE question(s), each question carries 6 marks.
4-pole, 3-phase, 50 Hz induction machine, the slip-rings of the machine are open- circuited. The frequency of the voltage across slip-rings is 75 Hz. Find the speed at which the rotor is driven.
No-load speed of a 3-phase 50 Hz induction motor is 1485 rpm. Find the number of alterations per minute which the rotor emf will make and the speed of rotor mmf with respect to rotor wound.
Stator of a 4-pole, 3-phase induction machine is supplied from 3-phase, 50 Hz supply and a prime-mover drives its rotor at a speed of 750 rpm. The slip-rings of the machine are open-circuited. Find the frequency of the voltage across any two slip-rings.
Limitations of induction generator.
Condition for maximum torque in a 3-phase induction motor.
Rotating fields of the stator and rotor are stationary with respect to each other.Â
What happens to a 3-phase induction motor if one of its three supply-leads gets disconnected.Â
6-pole, 50 Hz single-phase induction motor runs at a speed of 900 rpm. Calculate the frequency of current in the cage rotor.
3-phase induction motor, maximum torque of 100 Nm occurs at a slip of 10%. Calculate the torque at a slip of 5%.
Explain Why does a 3-phase induction motor always run at a speed less than the synchronous speed.
Synchronous Machines 5th Sem BTEE-501 B.Tech EE PTU Sept 2020 Paper Click Here
MY YOUTUBE CHANNEL
JK Smart Classes Upload Lecture for Degree classes like B.TECH,M.TECH in any stream like ECE,EE,ME and Civil Engineering
JK SMART CLASSES
ER.JASWINDER KUMAR
JK SMART LECTURE
ER.JASWINDER KUMAR
Engineering Classes Upload Lecture for Polytechnic Diploma classes in any stream like ECE,EE,ME and Civil Engineering
ENGINEERING CLASSES
ER.JASWINDER KUMAR
er.jaswinder kumar
Senior Lecturer