Andhra University BE/B.Tech Elements of Eletrical Engineering Previous Paper 2008
First question is compulsory.
Answer any FOUR from the remaining questions.
All questions carry equal marks.
Answer all parts of any question at one place.
1. (a)With respect to an inductance motor define slip.
(b) What is meant by dynamically induced emf?
(c)Define hysterisis loss.
(d) List types of DC grnerator.
(e)Give the EMF equation of DC generator.
(f)Give Maximum Torque equation for a 3-ɸ induction motor.
(g)Draw equvalent circuit and transformer.
2.(a) Describe Faradays’s laws of Electromagnetic induction.
(b)A coil of 100Ω is placed in a magnetic flux of 1m wb.the coil has 500 turns and a galvanometer of 400Ω resistance is connected in series with it.The coil is moved in 0.1 sec from the given field to 0.3 wb find,
(i)An average induced emf
(ii)Average current through the coil.
3.(a) What do you understand by the self excited generators?Describe with neat sketches the shunt field generator.
(b) A 4 pole shunt generator with lap winding supplies a load of 200A at 200V.Shunt field resistance 50Ω and armature resistance 0.05Ω.caluclate
(i)the total armature current
(ii)current per parallel path
(iii)E.M.F generated ;allow a brush centered drop as 2V
4.what do you understand by the effeciency of D.C.motor?
Describe any method of determining the effeciency of d.c.Motor.
5.How will you measure the power of an inductive load using the two watt meter method?
Draw connection diagram.
6.Deduce the e.m.f equation of an alternator.
7.A 75 KVA transformer has iron losses 500w and full load copper losses 1200w.find the effeciency at full load and at half load
(i) unity power
(ii) 0.8 p.f.lagging
8.what are the different types of starters used for starting the 3Ω induction motor ?
Describe in detail D.O.L Starter with neat sketch.
(b)A six pole 3ɸ induction motor runs at a speed of 960rpm and the shaft torque is 135.7nm.
Caluclatye the rotor cu losses if the friction and windage losses amount to 150 w.the frq. Supply is 50 c/shttp://www.stepinau.com/2013/09/26/andhra-university-beb-tech-elements-of-eletrical-engineering-previous-paper-2008/IT 2.1 Previous PapersCSE,CSE Previous Papers,Elements of Eletrical Engineering Previous Papers,IT,IT Previous Papers