Found a pulley calculator.... Pulley Calculator. RPM, Belt Length, Speed, Animated Diagrams
The Generac documents says it runs the propane engine at 1800 rpm, and it's direct drive to gen head.
I'll be connecting Mitsubishi Diesel engine to gen head via pulleys.
I'd like to stay around idle speed on Diesel engine, so I'm guessing 1000rpm.
If I use a 10" pulley on diesel engine, and a 5" pulley on gen head and 14" between centers... I'll be at 1:2 ratio
So, the 1000 rpm diesel engine compounds to 2000rpm on gen head and 900 rpm on diesel engine will compound to 1800rpm on gen head.
1) Am I wrapping my head around this correctly?
2) Can I slow the diesel engine down to 900rpm?
3) How would I add a tachometer to diesel engine, so I can adjust rpm?
4) Or do I need to reverse pulley sizes and adjust rpm from there?