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:
The Answer: Because an acre is a measure of area, not length, it is defined in square feet. An acre can be of any shapeâa rectangle, a triangle, a circle, or even a starâso long as its area is exactly 43,560 square feet.The most standard shape for an acre is one furlong by one chain, or 660 feet by 66 feet.To find the linear measurements of other rectangular acres, just divide 43,560 by the number of feet you want on one side.A square-shaped acre would then be about 208.7 by 208.7 feet (because 208.7 x 208.7 = ~43,560).An acre 100 feet wide would be 435.6 feet long (100 x 435.6 = 43,560) and an acre 1 foot wide would be 43,560 feet long. square-shaped acre would then be about 208.7 by 208.7 feet (because 208.7 x 208.7 = ~43,560). An acre 100 feet wide would be 435.6 feet long (100 x 435.6 = 43,560) and an acre 1 foot wide would be 43,560 feet long.