The starter motor in an automobile has a resistance of 0.41 in its armature wind

Question

The starter motor in an automobile has a resistance of 0.41 in its armature windings. The motor operates on 12 V and has a back emf of 10 V when running at normal operating speed. How much current does the motor draw

Part A) How much current does the motor draw when running at its operating speed? Express your answer using two significant figures.

Part B) How much current does the motor draw when running at half its final rotational speed? Express your answer using two significant figures

Part C) How much current does the motor draw when starting up? Express your answer using two significant figures.

Explanation / Answer

Given:R=0.41ohm,V2=12V,V1=10V

Use V = I*R

a) So I = V/R = (12-10)/0.41 = 4.88A The back emf reduces the effective voltage
b) 12/0.41=29.26A
c) I = V/R = (12)/0.41 = 29.26A At start there is no back emf

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.