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A192015 Pages: 2

turns. It is found that a current of 4A in the winding produces a flux density of

IT in the air gap. Find the relative permeability of mild steel

Find the values of circuit elements in a two element series circuit which (6)
consumes 700W at a power factor of 0.707 leading. The applied voltage is a
single phase ac voltage given by v = 141.4 sin (3141).

In two wattmeter method of three phase power measurement the total power (4)
measured was 30kW at a power factor of 0.7 lagging. Find the reading of each
wattmeter.

With a neat diagram , explain the generation of balanced three Phase alternating (6)
voltage. Also draw the three phase voltage waveform.

A resistance of 120Q and capacitive reactance of 250Q are connected in series (4)
across a single phase ac voltage source. If a current of 0.9A is flowing in the

circuit find (i)power factor (ii)supply voltage (iii)Active power (iv) reactive

power

Draw a neat schematic diagram of a Nuclear power plant and explain its (10)
operation.

Draw and explain the single line diagram of a typical power transmission system (7)

What is the need for high voltage transmission? (3)
MODULE 5
Answer any one full question, each carries 10 marks.
A DC motor rated at 500V takes a current of 40A. The resistance of the (8)

armature is 0.2 ohm. The machine has 6 poles and the armature is lap wound
with 864 conductors. If the flux per pole is 0.05Wb, calculate (1) speed of the
motor (ii) torque developed by the armature.

What will be the speed of the machine if the armature is wave wound. (2)

A transformer is rated 10011۷۸, 6600/400V. Determine the currents on high (10)
voltage and low voltage sides and turn ratio. If the maximum flux in the core is
0.02wb, find the number of turns on the primary and secondary.

MODULE 6
Answer any one full question, each carries 10 marks.
Explain the constructional details of squirrel cage and slip ring (10)
induction motor
Explain the principle of operation of a three phase induction motor. (6)
A 50Hz induction motor has 2 poles and runs at 2930 rpm. Calculate (4)
(i) The synchronous speed (ii) The percentage slip.

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