What percentage of stroke does the steam supply to the cylinder shut off once the piston has traveled?

The correct choice indicates that steam supply to the cylinder is typically shut off once the piston has traveled between 25 to 35% of its stroke. This practice is rooted in the design and efficiency of steam engines, especially in terms of optimizing the use of steam and enhancing overall performance.

When a steam engine operates, the piston moves through the cylinder, converting steam pressure into mechanical work. To achieve maximum efficiency and minimize steam loss, the steam admission is efficiently timed to coincide with the movement of the piston. Shutting off steam at around 25 to 35% of the stroke allows the engine to utilize the steam energy effectively, as it creates a balance between sufficient work being done by the piston while also allowing for the steam to expand and do work without wasting energy.

Employing this range helps manage the engine's performance, allowing it to maintain power output while avoiding operating under conditions that could lead to inefficiencies, such as consuming excessive steam or experiencing unnecessary wear on components. Understanding these operational parameters is fundamental for effective engine management in steam systems.