The ice cream unit is powered by a 1 HP John Deere hit and miss engine.
648 Marticville Road Pequea, Pennsylvania 17565
I have the belt system spring loaded so that the belt on the six quart will slip when the ice cream is ready. The power then shifts to the 10 quart; when that belt slips, the ice cream is ready, and then all the power shifts to the 20 quart. And it is ready when the final belt slips. Trial and error gave me the correct tension and torque on each of the drive belts of each freezer. The trick is to start the six quart first, and then get the 10 ready, and then after starting it, get the 20 quart ready. By the time the 20 quart is starting, the six quart is about done, and the 10 quart takes more power. By the time the 20 quart is laboring, the 10 quart is done, and all the power shifts to the 20 quart. Starting all freezers at the same time would eventually stall the engine before any of the ice cream is completely hard.
Incidentally, an old White Mountain technical paper suggests (hand-crank average) of 110 rpm for the 20 quart, 90 rpm for the 10 quart and 80 rpm for the six quart. With 550 rpm coming off the 4' pulley on the engine, I used different size (diameter) drive pulleys to achieve the recommended rpm at each freezer.