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:
This is an attempt to help you visualise how big an area one acre is. An acre measures an area of land and is about 70 yards by 70 yards, which means about 4,900 square yards (or roughly 44,000 square feet).