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10 ohm 5 ohm ‏من‎ 2 ohm

[` சிரி NWA |” சிரி

ஞூ ‏ل‎ 2 ~
1 10 ‏اہ‎ 8 T 560%
| -- 1 ~ |
12 A steel ring of 25 cm diameter and of circular section 3 cm in diameter has an air gap (10)

of 1.5mm length. It is uniformly wound with 1000 turns of wire carrying a current of
2A. Calculate i) magnetomotive force ii) magnetic flux density in air gap iii) magnetic
flux iv) relative permeability of steel ring. Assume that iron path takes about 40% of
the total mmf.

13 a) With the help of diagrams explain how an alternating voltage is generated using a (5)

single turn coil.
b) A resistance of 5 Q and an inductor of 15mH are connected in series across a 230% (5)

ணை ಬಾರಾ 7 50Hz single 77856 घट supply. Calculate te ti) current (ii) power factor (iii) power തത്ത

consumed (iv) What value of capacitor must be connected in series with this
combination so as to improve the power factor to 0.9.

14 A balanced three phase load consists of three coils each having resistance of 4Q and (10)
inductance 0.02H. It is connected to a 415V, 50Hz, 3-phase ac supply. Determine the
phase voltage, phase current, power factor and active power when the loads are

connected in (i) star (ii) delta

15 Draw a neat schematic diagram of a hydro-electric power plant and explain the (10)
functions of various components.
16 Explain any two types of available non-conventional energy sources. - (10)
MODULE 5

Answer any one full question, each carries 10 marks.
17 a) Derive the emf equation of a DC generator. (4)
b) With connection diagram , explain the different types of DC generators based on the (6)
type of field excitation given.
18 a) What are the different types of losses occurring in a transformer? (2)
b) Write the expression for efficiency of a transformer. (2)
c) A single phase transformer has 400 primary turns and 1200 secondary turns. Primary (6)
winding is connected with 500V,SOHz supply. Find the flux density in the core and

emf induced in the secondary winding. Cross sectional area of the core is 50cm?.

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