This High Speed engine was built by the Armington & Sims Engine Company, Eagle Street, Providence, RI. It was delivered to the Hartford Electric Light Company in 1883. It was connected to a Thomson-Houston Electric Company generator that would power 28 lights. It has a 9.5″ bore and a 10″ stroke and produces 50 Horsepower at 350 RPM with 175 PSI of steam. This square design is still the preferred ratio of bore to stroke. It has a balanced crankshaft and a Rites governor. This engine design was also used by Thomas Edison to drive his generators at Pearl Street. Henry Ford was chief engineer at Detroit Edison Electric light before he made automobiles. Both Edison and Ford thought highly of the Armington & Sims engines.
This engine and generator was donated to the NEWSM by the Connecticut Light and Power Company in 1999. When received, the engine was missing the piston, piston valve, piston rod, and valve rod. Replacement parts were made by the Thursday crew and the engine now runs.