Electrical estimation model question paper

TAMIL NADU POLYTECHNIC COLLEGE(AUTONOMOUS ) MADURAI 11.

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING.

MODEL EXAMINATION -SEPTEMBER 2010

13062-ELECTRICAL ESTIMATION

Time: 3 hours                                                                Max. Marks:75

Note:

(1) Answer all questions.

(2) Cost of materials may be assumed suitably if necessary.

(3) Electrical estimation tables may be permitted in the examination hall.

  PART- A                                                                                                                                                 

                                                                                              (5 MARKS)

1.     Draw the conventional symbol to represent the following

a)     Distribution fuse board with suitable switch power.

b)    Heater.

c)     Sockect outlet 15 ampes..

d)    3-Phase auto transformer.

e)     Circuit Breaker.

PART-B                        (20 MARKS)

     2. Write down the relevant I.E rules with reference for the following

                a) Meter,maximum demand indicators & other apparatus

                    on consumer premises.

                b) Testing of consumer instation.

     3.Write down the specifications of the following:

               a) Energy meter 1-phase and sodium vapour.

               b) 250 KVA,Distribution transformer.

                                                       PART- C                        (20MARKS)                                                                       

      4. Answer briefly any four questions

1.     Compare the differnce type of wiring.

2.     Explain why the fuse isn’t provided in neutral.

3.     What is service connection ?Explain how under ground service connections are given to the consumer?.

4.     Describe the method of pipe Earthing.

5.     Mention the value of earth resistance and factors on which it depends on.

6.     Explain about Leakage Test.

5. Answer either (a) or (b).                                                       (30MARKS)

         (a)    Estimate the quantity of materials required for wiring a computer centre of size 10m*6m*3m height, having the following electrical load.

v Number of computer system: 10

v No. Tube Light Fittting: 10

v No. of Ceiling Fan: 04

v Window model a/c unit: 1.5ton, 2 nos.

v No. of  scanner:1

v No. of printer: 2

Draw a suitable installation plan, single line wiring diagram and estimation the quantity of materials required with specification. Type of wiring proposed is concealed conduit system. Assume necessary data as per IE rules and mention them clearly.

(or)

(b) A small workshop 30m*15m has to be equipped with the following machinery

v One lathe driven by 3 H.P, 415 V, 3 phase induction motor.

v One shaper Machine driven by 5 H.P, 415V, 3 phase induction motor.

v One grinding machine driven by 1 H.P, 415V, 3 phase induction motor.

v One drilling machine driven by 0.5 H.P, 230 V, 1 phase.

v One welding set of  10kVA, 415V, 3phase.

Draw a suitable installation plan for the above installation. Estimate the quantity of materials required with specification, for power wiring only. Draw the single line wiring diagram of electrical power distribution starting from main switch. The wiring is to be of surface conduit. Assume necessary data as per IE rules and mention them clearly.