The DC motor was the mainstay of electric traction drives on both electric and diesel-electric locomotives, street-cars/trams and diesel electric drilling rigs for many years. The introduction of DC motors and an electrical grid system to run machinery starting in the 1870s started a new second Industrial Revolution.
One acre is 43,560 sq ft. One half acre is 21,780 sq ft. However, that doesn't help most people much when trying to picture how large a lot is. Half acre lot is roughly:
There are 43,560 square feet in one acre.   An acre is a unit of area. 640 acres equal a square mile. Hence, it is 1/640 of a square mile. Since a square mile contains 2â¦7,878,400 square feet, an acre is 27,878,400 divided by 640, which is 43,560 square feet. Remember: an acre can be converted to SQUARE feet, not plain (linear) feet. Square feet and feet are not the same units. A foot is unit of distance.