A 225kW, 250 V 1280 rev/m dc motor has windage, friction, and iron losses of 8 kW. It drives a large flywheel, and the total moment of inertia of the flywheel and armature is 177 kgm². The motor is connected to a 210 V de source, and its speed is 1280 rev/m just before the armature is switched across a braking resistor of 0.2 ohms. If this motor is plugged and the braking resistor is increased to 0.4 ohms so that the initial braking current remains the same as before, calculate: (a). the initial current and breaking power (b). the stopping time. (c). Define armature reaction and state any adverse effect it has on the de machine

A 225kW, 250 V 1280 rev/m dc motor has windage, friction, and iron losses of 8 kW. It drives a large flywheel, and the total moment of inertia of the flywheel and armature is 177 kgm². The motor is connected to a 210 V de source, and its speed is 1280 rev/m just before the armature is switched across a braking resistor of 0.2 ohms. If this motor is plugged and the braking resistor is increased to 0.4 ohms so that the initial braking current remains the same as before, calculate: (a). the initial current and breaking power (b). the stopping time. (c). Define armature reaction and state any adverse effect it has on the de machine

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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