A manufacturing company is considering purchasing a 10 HP electric motor which it estimates will run an average of 6 hours per day for 250 days per year.
Past experience indicates that:
(1) its annual cost for taxes and insurance averages 2.5% of first cost,
(2) it must make 10% on invested capital before income tax considerations, and
(3) it must recover capital invested In machinery within 5 years.
Two motors are offered to the company. Motor A. costs $340 and has a guaranteed efficiency of 85% at the indicated operating load. Motor B costs $290 and has a guaranteed efficiency of 80% at the same operating load.
Electric energy costs the company 2.3 cents per KW-hr. Calculate the annual cost of each motor and indicate which motor should be purchased.