Give two basic speed control scheme of DC shunt motor?

Give two basic speed control scheme of DC shunt motor?
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Answer: 1. By using flux control method: in this method a rheostat is connected across the field wdg to control the field current. So by changing the current the flux produced by the field wdg can be changed, and since speed is inversely proportional to flux speed can be controlled. 2. Armature control method: in this method a rheostat is connected across armature wdg and by varying the resistance the value of resistive drop (IaRa) can be varied, and since speed is directly proportional to Eb-IaRa the speed can be controlled.
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