Jawaharlal Nehru Technological University Anantapur 2011-1st Sem B.Tech Civil Engineering II ester(R09) Supplementary s, "Electrical and Mechanical Technology" - Question Paper

Code :9A02303
II B.Tech I Semester(R09) Supplementary Examinations, May 2011
ELECTRICAL & MECHANICAL TECHNOLOGY
(Civil Engineering)
Time: three hours Max Marks: 70
(Note: Minimum of 2 ques. from every part should be chosen for answering five
questions)

PART-A
1. (a) With a neat sketch, discuss the working of a 3 point starter for D.C shunt motor.
(b) Derive the expression of back EMF in a D.C motor and briefl y define its role.
2. (a) Derive the condition for maximum efficiency of a transformer.
(b) A 30 KVA single phase transformer has an iron loss of 457 watts and copper loss of 125 watts
when delivering half the full load. At what percentage of full load will the transformer have
maximum efficiency.
3. (a) discuss the constructional features of alternator.
(b) A three phase, six pole alternator is coupled to an engine running at 1200 rpm. The alternator supplies
an induction motor which has a full load speed of 1164 rpm. obtain the slip and number of poles
of the motor.
4. (a) discuss with neat sketch, the principle of operation of permanent magnet kind moving coil instrument.
(b) explain the classification of electrical instruments.
PART-B
5. (a) discuss the principle of arc welding. provide the list of equipments needed is general for electric
arc welding.
(b) define the TiG welding method and its specifi c applications.
6. (a) discuss with help of neat sketch the working of a steam engine.
(b) discuss with neat sketch closed cycle gas turbine plant.
7. (a) In a 2 stage compressor, prove that the work done on 1kg of air is minimum with perfect
intercooling when the intermediate pressure is the geometric mean of the suction and delivery
pressure.
(b) Deduce the relation ranging from the tension on the tight side and slack side of a belt connecting two
pulleys and transimitting power. Neglect the centrifugal eff ect of the belt mass.
8. (a) discuss the block diagram of a vapour compresson refrigeration system.
(b) discuss the belt and bucket conveyers with neat sketch. How can these conveyers are used as
mechanical handling equipments?

Earning:   Approval pending.