- #1
songoku
- 2,328
- 335
Homework Statement
A motor has both resistance and inductance. A motor rated at 1 hp input operating at 240 V draws 4 A of current because
a. power is lost due to resistance
b magnetic saturation robs power
c. inductance does not consume power
d. friction in the bearings of the motor
e. (a) and (b)
Homework Equations
P = VI
The Attempt at a Solution
I try to calculate the current :
P = 1 hp [tex]\approx[/tex] 746 W
[tex]I = \frac{P}{V} = \frac{746}{240} = 3.1 A[/tex]
In fact, the current drawn is bigger. I think maybe this has something to do with back e.m.f. but when back emf exists, the current drawn should be smaller (below 3.1 A). Can someone give me a hint to think about?
Thanks