UNIT-I ALTERNATORS 1. What principle is used in Alternators? 2. What are the requirements of an alternator? 3. Mention the types of alternator rotor. 4. What is hunting in alternators? 5. What are the two types of alternator? 6. Name the types of armature winding? 7. Write the formula to calculate the synchronous speed of alternator. 8. Define slot angle. 9. What are the methods obtaining sine wave in alternator? 1o. Write the expression for EMF equation of alternator? 11. State different methods of cooling of alternator? 12. Write the relation between frequency, speed and number of poles. 13. Derive the relation between frequency and number of poles. 14. What is pitch factor? 15. What is distribution factor or breadth factor? PART B 1. Explain the stator and rotor constructional details of salient pole alternator? 2. Derive an expression for EMF of alternator taking into account the pitch factor and distribution factor? 3. Explain the methods of obtaining sine wave in salient pole alternators with neat sketches? 4. Explain with a neat sketch the constructional details of turbo alternator? 5. Describe hydrogen cooling of alternators and state its advantages. 6. Explain with sketches the different methods of cooling of alternators? 1
UNIT-II PERFORMANCE OF AN ALTERNATOR PART A 1. What is effective armature resistance? 2. What is leakage reactance? 3. What is synchronous reactance? 4. What is armature reactance? 5. What is synchronous impedance? 6. What is armature reaction in alternator? 7. Mention the methods used for synchronization? 8. What is meant by voltage regulation? 9. Write the expression for no load emf. 1O. Write the formula for regulation. 11. Write the formula for synchronizing power, synchronizing torque and synchronizing current. 12. What is synchronizing of alternators? 13. Mention the methods used to find out the regulation of alternators. 14. Name the two methods for determining the voltage regulation of alternator. 15. State two seasons for voltage drop in alternator. 1. Explain the EMF method (or) synchronous impedance method of predetermining the voltage regulation of an alternator. 2. With schematic diagram explain briefly the synchronizing of two 3 phase alternators by dark lamp method. 3. Explain briefly the synchronizing of two three phase alternators by bright lamp method. 4. Explain the armature reaction in alternator for various power factor loads. 5. Describe the synchronizing of two three phase alternators by synchroscope method. 6. Explain in detail the ampere turn method of calculating the regulation in an alternator. 2
UNIT-III THREE PHASE INDUCTION MOTOR 1. Mention the types of 3 phase induction motor. 2. Define slip in induction motor. 3. Write the expression for the slip in induction motor. 4. Write the relation between the slip frequency. 5. Write the conditions to obtain maximum starting torque. 6. Write the condition to obtain maximum torque at running condition? 7. What type of starter is suitable for three phase slip ring induction motor? 8. Name the methods of speed control of 3 phase induction motor. 9. What is meant by cogging in 3 phase induction motor and how it is prevented? 1O.What is meant by crawling in induction motor? 11. Define slip in induction motor. 12. Draw the approximate equivalent circuit of induction motor. 13. Why is the speed control by rotor resistance method not suitable for 3 phase squirrel cage induction motor? 14. What is meant by cascading of two induction motors and state four possible speeds in terms of poles and frequency? 15. Mention the starters used for 3 phase induction motor. 1. Explain the working of an induction motor. 2. Explain with sketches the constructional details of slip ring induction motor. 3. Explain with sketch the constructional details of 3phase induction motor. 4. Explain the slip torque characteristics of a 3 phase slip ring induction motor and show the influence of rotor resistance on this characteristic. 5. How are equivalent circuit constants of an induction motor determined for assumed slip? 6. Explain the Rotor-resistance method of speed control an induction motor. 7. Explain with a neat diagram the working of a star delta starter and mention its merits and demerits. 3
8. Explain with a neat sketch the working of an auto transformer starter. Bring out merits and demerits. UNIT-IV SINGLE PHASE INDUCTION MOTOR 1. At what speed does synchronous motor run? 2. Name the machine, which works only at synchronous speed. 3. Name the four methods of starting a synchronous motor. 4. What is the use of damper winding in a synchronous motor? 5. What will be the power factor when the synchronous motor is over excited? 6. What will be the power factor when the synchronous motor is under excited? 7. Single phase induction motor is not self starting, why? 8. What are the main parts of split phase induction motor? 9. Name the four methods of starting a synchronous motor. 1O.What is V curve and inverted V curve? 11. State the application of synchronous motor. 12. Mention the types of 1 phase induction motor. 13. Mention the types of capacitor type induction motor. 14. State the applications of split phase induction motor. 15. State the applications of capacitor start motor. 1. Explain the principle of operation of synchronous motor. 2. Explain any two methods of synchronous motor. 3. Explain v curve and inverted v curve of synchronous motor. 4. Explain the double field revolving theory for single phase induction motor. 5. Explain the construction and working principle of split phase induction motor. 6. Explain the construction and principle of operation of capacitor start Induction motor and state its applications. 7. Explain the construction and principle of capacitor start and capacitor run induction motor. 4
UNIT-V MAINTENANCE OF AC MACHINES 1. What is single phasing? 2. What is meant by Degreasing? 3. A motor fails to start, state any two causes. 4. How will you check unbalancing in rotor? 5. Mention any two starter troubles. 6. State any two qualities of good transformer oil. 7. Why B.D.V. test is conducted on transformer oil? 8. What is drying out? 9. Name the different types of transformer oil purifiers. 1O.What is a Buchholz relay? 11. Name the tests to be carried out for testing the distribution transformer. 12. State any two causes of the transformer noise. 13. Define earthing. 14. What is the use of earthing? 15. State the methods of earthing. 1. What do you mean by single phasing? Explain how single phasing is prevented using current operated relays. 2. What are the causes of noise and vibration while running of a induction motor? 3. What are the checks to be done before commissioning of an induction motor? 4. Explain the common troubles that are occurring in induction motor starters and how they are rectified. 5. Explain the effect of unbalanced supply on the performance of induction motor. 6. Explain in detail the dismantling procedure for distribution transformers. 7. Explain in detail the working of Buchholz relay. 8. Explain about transformer troubles and their causes. 9. Explain with neat sketch about the measurement of earth resistance. 5