Thi Qar University Electrical Machines Electrical and Electronic Dept. 'Speed Control of DC Motors' H.W Ql: 220V, 7 Hp DC series motor coupled to a fan, the motor draws 25 A and runs at 300 rpm at terminal voltage of 220V and no external resistance, torque of the fan is proportional to the square of the speed, if Ra-0.6 2 and Rf-0.4 2. (Neglect rotational losses): a) Determine the power supplied to the fan and torque developed by the motor. b) The speed is to be reduced to 200 rpm by inserting external resistance, determine the value of this resistance and the power delivered to the fan.

Thi Qar University Electrical Machines Electrical and Electronic Dept. 'Speed Control of DC Motors' H.W Ql: 220V, 7 Hp DC series motor coupled to a fan, the motor draws 25 A and runs at 300 rpm at terminal voltage of 220V and no external resistance, torque of the fan is proportional to the square of the speed, if Ra-0.6 2 and Rf-0.4 2. (Neglect rotational losses): a) Determine the power supplied to the fan and torque developed by the motor. b) The speed is to be reduced to 200 rpm by inserting external resistance, determine the value of this resistance and the power delivered to the fan.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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