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(3%) Problem 22: A motor operating on a 275 V source has a 185 V back emf at ope

ID: 1582680 • Letter: #

Question

(3%) Problem 22: A motor operating on a 275 V source has a 185 V back emf at operating speed and draws a 15 A current 50% Part (a) What is its resistance in ? Grade Summary Deductions Potential 0% 100% sin cosO cotan0 asin) acos0 Submissions Attempts remaining: Z tan() ( % per attempt) detailed view sinhO 1 23 0 atan0acotan) si cosh0 n cotanh0 Degrees O Radians 0 Submit Hint I give up! Hints: 0% deduction per hint. Hints remaining: 3 Feedback: 0% deduction per feedback Submission History Answer Hints Feedback Totals Totals 0% 0% 0% 0% - 50% Part (b) What current does it draw when it is first started in A?

Explanation / Answer

here,

EMF = 275 V

Back emf , V = 185 V

current , I = 15 A

a)

the resistance , R = (EMF - V)/I

R = ( 275 - 185)/15 ohm

R = 6 ohm

the resistance is 6 ohm

b)

when it started

the back EMF is zero

the current drawn , I' = EMF/R

I' = 275/6 = 45.8 A