(c) A moving coil voltmeter with a resistance of 20 N gives a full-scale deflection of 120° when a potential difference of 100 mV is applied across it. The moving coil has dimensions of 30 mm x 25 mm and is wound with 100 turns. The control spring constant is 0.375× 10ª Nm/deg. Find the flux density in the air gap. Find also the diameter of copper wire of coil winding if 30% of instrument resistance is due to coil winding. The specific resistance of copper = 1.7 x 10* Nm. %3D

(c) A moving coil voltmeter with a resistance of 20 N gives a full-scale deflection of 120° when a potential difference of 100 mV is applied across it. The moving coil has dimensions of 30 mm x 25 mm and is wound with 100 turns. The control spring constant is 0.375× 10ª Nm/deg. Find the flux density in the air gap. Find also the diameter of copper wire of coil winding if 30% of instrument resistance is due to coil winding. The specific resistance of copper = 1.7 x 10* Nm. %3D

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter29: Dc Generators

Section: Chapter Questions

Problem 1PA: You are working as an electrician in a large steel manufacturing plant, and you are in the process...

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A moving coil mili voltmeter has a resistance of 20 ohm and full scale deflection of 120 degrees is reaches when the p.d of 100V is applied across it's terminals. The moving coil has effective dimensions of 3.1cm x2.6cm and wound with 120 turns. The flux density in the air gap is 0.15 Weber per meter squared. Determine the control constant of the spring and suitable diameter of copper wire for a coil winding if 55% of the total instrument resistance is due to coil winding given resistivity of 1.73*10-8 ohm meter
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