Question
Download Solution PDFA 200 V d.c machine has Ra = 0.5 Ω and its full-load la = 20 A. Determine the induced e.m.f when the machine acts as a motor.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
Voltage equation for dc machine working as the motor is
Vt = Eb + IaRa
Where,
Vt is the terminal voltage
Eb is induced emf or back emf
Ia is armature current
Ra is armature resistance
Calculation:
Given that,
Vt = 200 V
Ia = 20 A
Ra = 0.5 Ω
Therefore, induced emf in the dc motor is
200 = Eb + (20 × 0.5)
⇒ Eb = 200 – 10 = 190 V
Last updated on Jun 16, 2025
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