Electrical Machines-II SPPU Endsem Question Paper Nov 2023
All 8 questions from this SPPU endsem paper, as printed. Read them here or open the PDF.
- Subject code
- 303143
- Pattern
- 2019 pattern
- Exam
- Endsem
- Session
- Nov 2023
- Max. marks
- 70
- Time
- 2½ Hours
- Semester
- I
- Paper code
- [6180]-77
Printed for: T.E. (Electrical Engineering)
Instructions to the candidates
- Solve Q1 or Q2, Q3 or Q4, Q5 or Q6, Q7 or Q8.
- Figures to the right indicate full marks.
- Neat diagrams must be drawn, wherever necessary.
- Assume suitable additional data, if necessary.
- Use of non-programmable calculator is allowed.
Questions
Q1
- a)[4]
Draw the equivalent circuit diagram of 3 phase synchronous motor & state, why it is called doubly fed motor.
Also asked:May 2024
- b)[6]
Draw the phasor diagram of 3 phase synchronous motor for lagging power factor & show i) Load angle ii) Internal angle iii) Power factor angle on it iv) Write the formula for back emf from phasor diagram.
Also asked:May 2023
- c)[8]
A 2300 V three phase star connected synchronous motor has armature resistance of 0.2 ohm/ph. and synchronous reactance of 2.2 ohm/ph. The motor is operated at 0.5 leading power factor and takes a current of 200 A from supply. Calculate back EMF generated in the motor & load angle .
Also asked:May 2024
OR- a)
Q2
- a)[4]
Sketch V and inverted V curves of synchronous motor and show the power factor regions.
Also asked:May 2024
- b)[6]
What is hunting in synchronous motor? How to minimise it? Explain.
Also asked:May 2024
- c)[8]
A 75 kW, 440 V, three phase star connected 50 Hz, synchronous motor has Zs = 0.04 + j0.4 /ph & operates at 0.8 leading power factor. The motor efficiency is 92.5 %. Calculate : i) armature current ii) back emf and iii) mechanical power developed in armature Pm.
Also asked:May 2023
- a)
Q3
- a)[3]
State the methods of speed control of 3 phase Induction motor on stator & rotor side.
- b)[6]
Draw the block diagram & explain the V/f method of speed control of 3 phase induction motor.
- c)[8]
With the neat construction diagram and explain the working of variable reluctance stepper motor. Show the truth table. How to reverse the direction of rotation.
OR- a)
Q4
- a)[3]
Calculate step angle & resolution of 3-ph stepper motor with 08 stator poles & 06 rotor poles.
- b)[6]
How the Energy Efficient three phase Induction Motor differ from Standard motor.
- c)[8]
With the neat diagram describe the construction and working of PM A.C. motor. State its applications.
- a)
Q5
- a)[4]
Draw the torque speed characteristics of AC and DC series motor on common axis & comment on armature current & torque.
- b)[6]
Compare conductively compensated and inductively compensated series motor.
- c)[8]
This part has equations that don’t show as text. Open the PDF to read it.
OR- a)
Q6
Q7
- a)[3]
State the types of 1-ph induction motors. Write applications of capacitor start IM.
Also asked:May 2024
- b)[6]
How to reverse the direction of rotation of 1-ph induction motor, explain by connection diagram.
Also asked:May 2023
- c)[8]
Sketch the torque-slip characteristics of 1-ph Induction motor based on double field revolving theory. Prove, how the 1-ph induction motor is not self-starting.
OR- a)
Q8
- a)[3]
- b)[6]
Draw the equivalent circuit of 1-ph induction motor under no load and blocked rotor test. Write the necessary formulae used.
Also asked:May 2024
- c)[8]
This part has equations that don’t show as text. Open the PDF to read it.