Q18 Moving coil used in a PMMC voltmeter of (0-300V) has a depth of 3 mm and a width of 2.5 cm. With 100 number of turns the coil spreads flux at a density of 10 mWb/m?. The voltmeter has an internal resistance of 10 ohms. Then, i. Calculate the Control torque produced by the coil, when it is set to measure 250V. ii. Estimate the spring constant of the spring used, when pointer makes 30° deflection for the measurement of 120V. iii. Mention the consequence when control torque produced is more than deflection torque in a PMMC instrument.

Q18 Moving coil used in a PMMC voltmeter of (0-300V) has a depth of 3 mm and a width of 2.5 cm. With 100 number of turns the coil spreads flux at a density of 10 mWb/m?. The voltmeter has an internal resistance of 10 ohms. Then, i. Calculate the Control torque produced by the coil, when it is set to measure 250V. ii. Estimate the spring constant of the spring used, when pointer makes 30° deflection for the measurement of 120V. iii. Mention the consequence when control torque produced is more than deflection torque in a PMMC instrument.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter11: Transient Stability

Section: Chapter Questions

Problem 11.18P

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