1. List the main parts of a d.c machine
2. What are the applications of D.C shunt and series motor?
3. The sinusoidal flux 0.2wb links with 55turns of a transformer secondary coil.
4. Calculate the RMS value of the Induced emf in the secondary. The supply
5. frequency is 50Hz.
6. Name the types of polyphase induction motor.
7. List the various methods of speed control of three phase induction motor
8. Define pitch factor and distribution factor.
9. What are the advantages of HVDC transmission system?
10. Name the types of insulators and its applications.
11. Define the voltage regulation of a trans former. Give the expression for the same.
12. Draw a no load phasor diagram of a transformer and explain the terms.
13. What is the condition for maximum efficiency?
14. A 3phase induction motor does not run at synchronous speed. Why?
15. Draw the speed – torque characteristics of induction motor.
16. Give the expression for Voltage Regulation.
17. Draw the phasor diagram of a transformer on leading power factor load.
18. Compare DC generator and alternator.
19. What are the different methods of speed control in Induction Motor?
20. What are the advantages of Rotating field over Rotating armature?
SUMMARY QUESTIONS
1) Derive the expression for generated emf in a d.c machine.
2) Draw a neat sketch of a d.c motor and label the component parts. Name the material
used for each component part.
3) Explain the operation of a three point starter used in a d.c motor.
4) Explain the speed control methods employed in a d.c motor.
5) Explain the structure of an electric power system and its parts in detail.
6) Explain the different types of EHVDC systems.
7) Sketch and explain the suspension type insulators
8) Derive the emf equation of an alternator.
9) Discuss briefly the constructional features of cylindrical rotor alternator. Why
do these alternators operate only with high speed steam turbines?
10) Derive the emf equation of alternator .
11) Explain the synchronous impedance method of determining regulation of an alternator.
12) Explain the principle of operation of a three phase induction motor.
13) Explain the torque Vs Slip characteristics of a slip ring induction motor
14) Derive the torque equation of an induction motor.
15) Explain the rotor side speed control schemes of three phase induction motor .
16) Derive the emf equation of transformer.
17) The primary and secondary windings of a 500KVA transformer have resistances of 0.4Ω and .001Ω respectively. The primary and secondary voltages are 6600V and 400V respectively.The iron loss is 3KW.Calculate the efficiency on full load. The load power factor being 0.8 lagging. Obtain the equivalent circuit of a single phase transformer.
18) A 40 KVA ,400/200 V , 50 Hz single phase transformer gave the following
results:
OC Test : 400 V , 5A , 500 W (HV SIDE OPENED)
SC Test : 10 V , 50 A , 150 W (LV SIDE SHORTED)
Draw the equivalent circuit of the transformer with the values shown and
calculate the terminal voltage when the transformer delivers the output at a
power factor of 0.8 lagging on LV side.
19) Explain the starting methods of single phase induction motor in detail.
20) What is the efficiency of a transformer and derive the condition for maximum
efficiency in a transformer .
21) Explain the direct method of testing a single phase transformer.
22) A three phase , 400 V , 50Hz ,4 pole Induction motor has star connected stator
winding. The rotor resistance and reactance per phase are 0.1 ohms and 1 ohms
respectively. The full load speed is 1440 rpm. Calculate the synchronous speed,
slip, rotor induced emf/ph and the torque developed by the motor on full load.(8)
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