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Two coils A and B arc connected in series across a 240
भ, 50 Hz ae supply, The resistance of A is 5 © and the
inductance of B is 0.015 H, If the input from the supply
is 3 kW and 2 kVAR, ‘find the inductance Of coil A and
resistance of coil Be Calculate the voltage across each
coil,

Answer two full Questions (J or and 19 or 2m

17 a. Derive the relation between Line and Phase Values of
Voltage and Current for a star connected system,

b.

A three phase star connected load consumes a total or 1
2 kW at a power factor of 0.8 lagging when connected to
a 3 phase. 400 V, SO Hz power supply.

Calculate the resistance and inductance of load per
phase.
OR

18 8. What is phase sequence Of a 3 phase system?

b.

Two single phase wattmeter are used to measure three phase power. The readings of
the two Watt mctcrs arc 2500 W and 450 W respectively, Calculate the Power factor

of the circuit. What would be the power factor if the reading Of the second wattmeter

is negative? (7)

19 a. Give the schematic Layout Of an LT Switch Board (5)

b.

What is the role of an ELCB in domestic wiring circuit? Also explain the working of

FLCB
OR

20 With a neat sketch, explain pipe earthing indicating required dimensions.