Question

Q1. Draw the equivalent circuits of a separately excited and a shunt DC motor. [20] Q2. Derive the speed-torque relation for a DC motor: [40] 0 = VR, Kø (KØ)??ind Q3. A DC motor's speed can be controlled by either changing the field resistance, changing the armature voltage or changing the armature resistance. Of these three, which one is the best method for DC motor speed control and which is the worst? Give reasons. [40]

Answer 1

Safova toly Exciteal DC Mater field Amm Vanmature Leac Shunt Cmotor Vaununal Shunt whnliy Armature Arom 1 (2. E-K.C Sence E in eg Patfry ualue

Kr Lin o ualue g Patiny V T.R + KC KT v.R) Кgco So C KT KE Kp R

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