23041-Electrical Machine - 2 Important questions (Updated)

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

23041-ELECTRICAL MACHINES II

STAFF-IN-CHARGE: N.SURESH KUMAR

IMPORTANT QUESTIONS

UNIT-I

1.      Explain the constructional details of turbo alternator [OCT 2014] [APRIL 2015] [OCT 2015]

2.      Derive the EMF Equation of an Alternator. (12)[APRIL 2013] [OCT 2014]

3.      What are the advantages of Hydrogen cooling. (12)[OCT 2013] [APRIL 2015]

4.      Why cooling is necessary on alternators? Explain any one method of cooling of alternator. [APRIL 2014] [OCT 2015]

5.      Explain the basic principles of salient pole type alternator with the help of a neat diagram. (12) [OCT 2013]

6.      Explain the constructional details of stator and rotor of a salient pole Alternator with neat diagram.[APRIL 2013]

7.      Compare the constructional features of squirrel cage salient pole rotor with diagram (any 6 points)[APRIL 2014]

8.      Explain the methods adopted to obtain sine wave shape of emf induced in the alternator. [OCT 2014]

UNIT-II

1.    An alternator has the following data (i) 3 phase alternator (ii) no. of poles =8 (iii) distribution factor=.985 (iv) flux/pole=.040 Wb (v) no. of slots on the armature=90 (vi) no. of conductor/slot=8 (vii) full pitched winding (viii) speed of alternator=600rpm. Determine the no load terminal voltage. [OCT 2013] [APRIL 2014]

2.    Explain the synchronizing of alternator by dark lamp method.[APRIL 2013] [APRIL 2014] [OCT 2014]

3.    What are the causes of voltage drop in alternator? Draw the vector diagram of a loaded alternator and determine the voltage regulation.[APRIL 2013]

4.    Explain load sharing of two alternator[OCT 2013]

5.    Explain the synchronizing of alternator by bright lamp method. [OCT 2015]

6.    Explain the effects of changing excitation of alternator [OCT 2014]

7.    Explain the following i) synchronizing of alternator ii)Necessity of parallel operation of alternator iii) Advantages of parallel operation of alternator iv)Conditions of parallel operation of alternator [April 2015]

8.    Explain Armature reaction of an Alternator [APRIL 2015]

9.    Explain the vector diagrams of alternator for led lag and unity power factor [OCT 2015]

10.  Draw neat circuit diagram and briefly explain open circuit and short circuit test.

11.  An alternator has the following data (a). Number of phases is 3 (b)Number of slots on the Armature is 90 (c)Number of poles is10 (d)Number of conductor per slot is 8 (e)Distribution factor is 0.965 (f)full pitched winding (g)flux per pole is 0.040 wb (h)speed of alternator is 600 rpm (i)Connection is star. Determine No Load Terminal voltage.

UNIT-III

1.      Explain No load and Blocked rotor test of 3 phase induction motor. [OCT 2013] [APRIL 2014]

2.      Explain how rotating magnetic field is produced in 3 phase induction motor by explaining the principle of its operation by means of a neat diagram. [OCT 2013] [OCT 2014]

3.      Compare squirrel case and slip ring Induction Motor[APRIL 2013]

4.      Explain the construction and principle of operation of induction motor. [April 2015]

5.      Explain star delta starter with the help of the control diagram.[APRIL 2013] [APRIL 2014]

6.      Auto transformer starter [OCT 2014]

7.      DOL starter [APRIL 2015]

8.      Explain the speed control of induction motor by injected emf method  [OCT 2015]

9.      Condition for maximum starting torque of an induction motor  [OCT 2015]

10.  Explain Rotating Magnetic Field produced by 3 phase 2 pole system

11.  Explain Rotor Resistance starter with a neat diagram

UNIT-IV

1.      Explain the double field revolving theory for single phase induction motor with neat diagram and why 1 phase induction motor not self starting? [OCT 2013] [OCT 2014]

2.      Explain the different methods of starting of 3 phase synchronous motor [APRIL 2014] [April 2015]

3.      Explain principle of working Split Phase Induction Motor [APRIL 2013] [OCT 2015]

4.      Explain ‘V’ Curve and Inverted ‘V’ curve of synchronous motor.[APRIL 2013]

5.      Explain effect of excitation on armature current and power factor of a synchronous motor. [OCT 2013]

6.      Construction and principle of operation of a synchronous motor. [OCT 2014]

7.      Single phase capacitor start induction motor [APRIL 2014]

8.      Explain capacitor Start and Run Motor with a neat diagram [April 2015]

9.      Effect of change in excitation of synchronous motor. [OCT 2015]

UNIT-V

1.      Explain any six points to be followed in installation and commissioning of induction motor. [OCT 2013] [OCT 2014]

2.      Explain any one method of Oil Purification[APRIL 2013] [OCT 2014]

3.      Write any six points for the common troubles and their remedies for induction motor starters [APRIL 2013] [April 2015]

4.      Explain the following tests 1)Voltage test 2)continuity test 3)short circuit test [APRIL 2014] [April 2015]

5.      Working of single phase prevention relay [APRIL 2014]

6.      a)What are the transformer troubles? Explain their causes.

b)What are the transformer noises? Explain their remedies. [OCT 2015]

7.      What are the causes of noise and vibration of an Induction Motor [OCT 2013]

8.      Explain the causes and remedies for following motor troubles:

i)                    Motor starts in wrong direction

ii)                  Motor produces excessive noise

iii)                Rotor runs at half speed

iv)                Bearings are over hot  [OCT 2015]

9.      Explain Transformer Earthing and Measurement of Earth Resistance.

***ALL THE BEST ***

24031-ELECTRONIC DEVICES AND CIRCUITS IMPORTANT QUESTIONS

DIPLOMA IN ELECTRICAL AND ELECTRONICS ENGINEERING

SUBJECT CODE   : 24031 

SEMESTER           : III SEMESTER

 SUBJECT TITLE   : ELECTRONIC DEVICES AND CIRCUITS  

STAFF-IN-CHARGE: N.DILLIBABU

IMPORTANT QUESTIONS

UNIT-I

PART-A

1.     Give an example for donor impurity.

2.     What is the cut in voltage for silicon diode?

3.     What is the peak inverse voltage of full wave rectifier?

4.     Name a component used for filtering.

5.     Give an example for intrinsic semiconductor.

6.     Draw the symbol of Zener diode

7.     What is the efficiency of half-wave rectifier?

8.     How many filtering components are used in pi filter?

PART-B

1.     Explain the operation of Zener diode and draw characteristics.(oct-12,13,14)

2.     Explain the operation of full wave rectifier and draw its output waveforms. List out its applications.(apr-13,14)

3.     Explain the operation and characteristics of PN junction diode with suitable diagram.(apr-13,14)

4.     Explain the operation of C and pi filter and draw its waveform.

5.     With a neat diagram , explain the working of  bridge rectifier.(oct-12,13,14)

UNIT-II

PART-A

1.     Draw the symbol of NPN transistor.

2.     What is the formula for current gain in common emitter configuration?

3.     Which bias is normally used in applications?

4.     What is the need for negative feedback?

5.     In which region transistor has to be operated for faithful amplification?

6.     What is the output impedance of common base configuration?

7.     What is Q-point?

8.     Name the types of feedback

PART-B

1.     (i) Explain the operation of transistor as an amplifier.(oct-12)

(ii) Write short notes on fixed bias. (apr-13)

2.     (i) Explain the operation of emitter follower.

(ii) Explain how transistor is used as a switch(apr-13)

3.     (i)Explain the operation of NPN transistor.

(ii) Compare three different configurations of transistors. (apr-13)

4.     Explain the operation of RC coupled(oct-12) amplifier and draw its frequency response.

5.     Explain the effect of  negative feedback(oct-12)

6.     Explain the operation of  BJT(oct-13)

UNIT-III

PART-A

1.     What is the condition for oscillation?

2.     What is the output frequency of Heartley oscillator?

3.     Mention the relationship between the parameters of JFET.

4.     State any two applications of UJT

5.     What are the components used in tank circuit?

6.     State the advantages of crystal oscillator.

7.     Give an example for voltage controlled device.

8.     What is the formula for intrinsic standoff ratio?

PART-B

1       (i) Discuss about the conditions for oscillation.

(ii) Explain the operation of RC phase shift oscillator.

2       Explain the working principle of JFET and draw its characteristics.(oct-13)

3       (i) Explain the operation of Hartley oscillator.

(ii) Differentiate FET with BJT (oct-12)

4       Explain the construction and operation of UJT.(apr-13)

5       Explain the operation of crystal oscillator(oct-12)

6       Explain the operation of colpitts oscillator(apr-14)

UNIT-IV

PART-A

1.     Give an example for unidirectional switch.

2.     Draw the symbol of TRIAC.

3.     Name the terminals of DIAC.

4.     Expand MOSFET.

5.     What is the family name of SCR?

6.     How many terminals are present in TRIAC?

7.     Expand DIAC.

8.     What are the types of MOSFET?

PART-B

1       (i) Explain SCR as a controlled rectifier.                                                        ii) Discuss about the specifications of SCR.

2       Explain the operation of  DE-MOSFET with neat diagram.

3       With neat diagram explain the working principle of SCR and draw the transistor analogy of SCR.(oct-12)

4       i)  Explain the operation of DIAC with its characteristics. (apr-13)                               ii) Explain the construction details of MOSFET.

5       Explain the operation of TRIAC with its characteristics.(OCT-13)

UNIT-V

PART-A

1.     Draw the symbol of LDR.

2.     What is solar cell?

3.     Draw the output waveform of negative clamper.

4.     How many stable states are present in Astable  Multivibrator?

5.     In which bias, LED emits light?

6.     Expand LASER.

7.     What is the other name for Astable  Multivibrator?

8.     Draw the output waveform of negative clipper.

PART-B

1.     Explain the operation of Solar cell and Photo Transistor. (APR-13)

2.     Explain the operation of Schmitt Trigger and draw its output waveform.(APR-14)

3.     Explain the operation of  i) Opto interrupter ii) avalanche photo diode. (OCT-14)

4.     Explain the operation of positive and negative clamper.

5.     Explain the operation of CLIPPER(oct-12)

6.     Explain the operation of monostable multivibter(oct-12)

7.     Explain the operation of voltage diubler(oct-12)

8.     LED,LCD.