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Jeff Conner                     Baldwinsville, NY       

Bruce-MacBeth 100 HP Stationary Gas Engine Electric Plant              11/5/2011          

A good friend, Doug Kelley and I started this engine project two years ago. We researched and documented an original engine at the Coolspring Power Museum in Coolspring, PA. We built two engines. The model is a 1/10th scale model of a 1912 vintage Bruce-MacBeth 100 hp stationary gas engine. This type of engine was used to drive generators, air and ammonia compressors, line shafts, etc. in continuous duty applications. The model uses a 1" x 1.2" b x s, and is fabricated from brass and steel. The flywheels were the only castings used. The prototype and model both use a top mounted camshaft driven by a vertical shaft from the center of the crankshaft through two pairs of miter gears. This camshaft design is unique only to Bruce-MacBeth engines as far as we know. The model incorporates water jacketed cylinders, heads, and exhaust manifold. Crankcase lubrication is by splash following the prototype. The ignition is CDI type with a distributor. The model was designed to run at a prototypical engine speed near 500 RPM. It does pretty well in the 500-700 RPM range.

The alternator follows an early Westinghouse design of the same era. It is a single bearing design driven directly off the crankshaft at engine speed. It operates at a maximum speed of 700 RPM and produces 120vac. 

The engine cooling system uses a radiator, circulating pump, and a variable speed fan powered by the alternator output. The cooling system handles the engine cooling needs for extended periods running under load. 

The video shows an early run with a crankcase inspection window installed. The window was a curiosity, but proved very helpful in resolving an over lubrication issue. The engine is shown pulling an electrical load of 25 watts and is running on propane fuel.



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