10/04/2026
On the operator’s platform of the 60 HP Case steam engine, you’ll notice the spinning balls. This is the steam engine governor.
The governor is an important part of the engine’s operation. Its job is to help maintain a relatively constant engine speed as the load on the engine changes. As the engine is put under a heavier load, the governor responds to the change in engine speed and adjusts the amount of steam being admitted to the cylinders.
The spinning balls are connected to a mechanism that reacts to engine speed. As the engine speeds up, centrifugal force causes the balls to move outward. As the engine slows down under load, the balls move inward. This movement operates the governor linkage and changes the steam admission to the engine.
Steam engineers commonly use the term “balls out” when an engine is working hard and the governor balls are spinning outward. You may hear an engineer say that the engine is “balls out” when it is under a heavy load.