The armature of a 270V dc shunt motor has a resistance of 0.20 ohm. If the armature current is not to exceed 85 amp, calculate: (a) The resistance that must be inserted in series with the armature at the instant of starting. (b) The value to which this resistance can be reduced when the armature accelerates until the counter emf becomes 171 volts. (c) The armature current at the instant of starting if no resistance is inserted in the armature circuit.

The armature of a 270V dc shunt motor has a resistance of 0.20 ohm. If the armature current is not to exceed 85 amp, calculate: (a) The resistance that must be inserted in series with the armature at the instant of starting. (b) The value to which this resistance can be reduced when the armature accelerates until the counter emf becomes 171 volts. (c) The armature current at the instant of starting if no resistance is inserted in the armature circuit.

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter5: Resistors

Section: Chapter Questions

Problem 1PA

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