At full load, when the DC shunt motor is supplied by 110 V dc source, the armature current is 20 A keeping the speed of the motor at 500 rpm. If the flux of the motor is weakened by 10%, the armature current drops to 15 A. By how much is the torque decreased?

At full load, when the DC shunt motor is supplied by 110 V dc source, the armature current is 20 A keeping the speed of the motor at 500 rpm. If the flux of the motor is weakened by 10%, the armature current drops to 15 A. By how much is the torque decreased?

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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Concept explainers

DC Series Motors

A DC motor is a type of electric motor which converts electric energy into mechanical energy. The forces that are produced by the magnetic field are what those common types of motors rely upon. Either electro-mechanical or electronic, all types of DC motors have some internal mechanism to change the current direction in part of the DC motors. As the DC motors could be powered from existing DC lighting power distribution systems, these motors were the first form of motors widely used. By changing the strength of the current in its field winding or by using a variable supply voltage, the speed of the DC motors can be controlled over a wide range.

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