240-V DC motor is connected long shunt. The armature resistance has 0.4 ohm, the series field resistance has 0.2 ohm, and the shunt field resistance has 240 ohms. If the armature takes 35 amp from the 240-V source. Find the efficiency of the motor if

240-V DC motor is connected long shunt. The armature resistance has 0.4 ohm, the series field resistance has 0.2 ohm, and the shunt field resistance has 240 ohms. If the armature takes 35 amp from the 240-V source. Find the efficiency of the motor if

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter32: Three-phase Motors

Section: Chapter Questions

Problem 6RQ: Name three factors that determine the torque produced by an induction motor.

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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.

Question

A 240-V DC motor is connected long shunt. The armature resistance has 0.4 ohm, the series field resistance has 0.2 ohm, and the shunt field resistance has 240 ohms. If the armature takes 35 amp from the 240-V source. Find the efficiency of the motor if the stray power loss is 900-W.

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