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:
How Many Square Feet in an Acre. Now that we know a bit about acres and square feet, we can move to conversion of these units and find out how many square feet there are in an acre. One US customary acre is equivalent to 43 560 square feet, 4840 square yards, or about 4047 square meters. There are also some other types of acres, used in various countries: Irish acre (7843 yd), Roman acre (1260 m), Cheshire acre (10240 yd), etc.