EE2302 Electrical Machines II B.E Question Bank : dmice.ac.in
Name of the College : DMI College OF Engineering
Department : Electrical And Electronics Engineering
Subject Code/ Name : EE 2302 – Electrical Machines II
Degree : B.E
Website : dmice.ac.in
Document Type : Question Bank
Electrical Machines II : https://www.pdfquestion.in/uploads/dmice.ac.in/1654-EE2302.docx
DMI Electrical Machines II Question Paper
Unit – I
SYNCHRONOUS GENERATOR :
PART-A :
Why is the field system of an alternator made as a rotor?
What is synchronous reactance?
What is meant by armature reaction in alternators? Nov 2012, Nov 2013)
Related : DMI College OF Engineering EE2403 Special Electrical Machines B.E Question Bank : www.pdfquestion.in/1661.html
What are the conditions for parallel operation of alternators?
What are the reasons for drop in voltage from no load to full load? (Nov -2012)
Why alternators are synchronized in power plant?
What you meant by single layer winding and double layer winding? (Nov -2011)
Define the terms ‘distribution factor’ and ‘pitch factor’
What are the various function of damper winding provided with alternator?
Why the stator core is laminated? (APR 2011)
Define voltage regulation. (Apr 2011, Nov 2013)
What are the test data required for predetermining the voltage regulation of an alternator by potier method?
What is meant by synchronous impedance of an alternator?
Calculate the pitch factor for the under given winding: 36 slots.4 poles coil span 1200 electrical.
Draw the OCC of an alternator
What are the test data required for predetermining the voltage regulation of an alternator by potier method?
State the advantages of stationary armature.
Calculate the distribution factor for a 36 slots.4 poles, single layer three phase Winding
Give any two difference between salient pole and cylindrical pole rotors.
What is capacity curves?
Unit – II
(i) With neat sketch describe the construction and principle of operation of salient pole alternator. (6) (NOV- 2012)
(ii) Derive the EMF equation of an alternator. (6) NOV-2010,2011, 2012, 2013)
(iii) A 4 pole alternator has an armature with 25 slot and 8 conductor per slot and rotates at 1500 rpm and flux per pole is 0.05 wb. Calculate the e.m.f generated, If winding factor is 0.96 and all the conductors are in series. (4) (Nov-2012)
2. (i) Elaborate the discussion on capability curve with its boundaries of synchronous machine.(8) (Nov-2010)
(ii) Discuss the parallel operation of two alternators with identical speed/laod characteristics(8) (Nov-2010)
3. (i) Define armature reaction and explain the effect of armature reaction on different power factor loads of synchronous generators. (8) (MAY- 2012)
(ii) Describe a method of synchronizing the 3 phase alternator to the infinite bus giving the relevant diagram(8) (MAY-2012)
4. Explain Clearly the ZPF method of determining regulation of an alternator.(10) (MAY-2012)
5. (i) A 2000 KVA, 11KV, 3-phase star connected alternator has a resistance of 0.3 O and reactance of 5 O/phase. It delivers full load current at 0.8 lagging power factor at rated voltage. Compute the terminal voltage for the same excitation and load current at 0.8 power factor leading. (10)
(ii) A 500 V, 50 kVA single phase alternator has an effective armature resistance of 0.2 . An excitation current of 10 A produces 100 A armature current on short circuit and an emf of 450 V on open circuit. Calculate synchronous reactance. (6)
6. (i) State and explain the conditions for parallel operation of alternators.(8)(Nov-2012
(ii) What is synchronizing power of an alternator? Derive an expression for the synchronizing power between the two alternators connected in parallel(8) (MAY-2012)
7. (i) Explain the determination of direct axis reactance Xd and quadrature axis reactance Xq using slip test (Nov -2011) (8)
(ii) For the salient synchronous machine, derive the expression for power developed as a function of load angle. (Nov -2011) (8)
8. (i) The following open circuit and sort circuit are made on a 6000KVA, 6600V,star connected,2 pole,60HZ turbine driven alternator. If I=12A at open circuit terminal voltage =8200V. with armature short circuited I=125A.IL=800A(line). At the rated load and UPF armature loss loss is 1.5 % of out put. Determine the percentage regulation at rated load and 0.8 p.f lag (8)(Nov -2011)
(ii) A 3 phase 16-pole alternator has star connected winding with 144 slots and 10 conductors per slot.the flux per pole is 0.04 wb and is distributed sinsoidally. The speed is 375 rpm. Find the frequency, phase emf and line emf.the coil span is 1200 electrical.(8)(Nov-2013)
9. (i) List the methods used to predetermine the voltage regulation of synchronizing machine and Explain the mmf method (12)
(ii) A 4-pole alternator has an armature with 25 slots and 8 conductors per slot and rotates at 1500 rpm and flux per pole is 0.05 Wb. Calculate the e.m.f generated, If winding factor is 0.96 and all the conductors are in series.(4) (Nov-2012)
10 (i) With a neat diagram explain the parallel operation of alternators by any one method. (12)
(ii) A 3 phase 6-pole star connected alternator revolves at 1000 rpm the stator has 90 slots and 8 conductors per slot. the flux per pole 0.05wb and is distributed sinusoidally. Calculate the voltage generated by the machine if the winding factor is 0.96.(4)(Nov-2010)