Question
Download Solution PDFThe armature resistance of a 220 volt DC machine is 0.5 ohm. What is the value of the back EMF when the machine functions as a motor if the full load armature current is 25 amps?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept
The circuit diagram of the DC motor is:
\(E=V-I_aR_a\)
where, V = Terminal voltage
E = Back EMF
Ia = Armature current
Ra = Armature resistance
Calculation
Given, V = 220 volts
Ia = 25 A
Ra = 0.5 Ω
\(E=220-25\times 0.5\)
E = 207.5 V
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