An automobile starter motor has an equivalent resistance of 0.0500 Ohm and is su
ID: 1642905 • Letter: A
Question
An automobile starter motor has an equivalent resistance of 0.0500 Ohm and is supplied by a 12.0 V battery with a 0.0080 Ohm internal resistance. (a) What is the current (in A) to the motor? ______ A (b) What voltage (in V) is applied to it? _______ V (c) What power(in kW) is supplied to the motor? ______ kW (d) Repeat these calculations for when the battery connections are corroded and add 0.0900 Ohm to the circuit. (Significant problems are caused by even small amounts of unwanted resistance in low-voltage, high-current applications.) current ____ A voltage ______ V power _______ kWExplanation / Answer
a )
applying K V L
we get E - i r = i R
i = E / r + R
i = 12 / 0.008 + 0.05
i = 206.89 A
b )
the voltage applied V = i R
V = 206.89 X 0.05
V = 10.344 volts
c )
power
P = i2 R
P = 206.892 X 0.05
P = 2140.17 W
P = 2.14017 kW
d )
i = 12 / 0.008 + 0.05 +0.09
i = 81.08 A
V = 12 X ( 0.05 / 0.05 + 0.008 + 0.09 )
V = 4.054 volts
P = V X i
P = 4.054 X 81.08
P = 328.69 W
P = 0.32869 kW