Which option describes the prescribed horsepower for the pump driver?

• A. Starting horsepower
• B. Rated horsepower
• C. Necessary brake horsepower
• D. Maximum horsepower

Answer: (C)

The question focuses on what amount of horsepower the pump driver must be able to deliver to operate the pump at the required discharge. That specific load is the necessary brake horsepower. It represents the actual horsepower the engine must supply at the pump shaft to overcome the pump’s mechanical load and system losses at the design operating point. It’s the real, demand-driven power the driver must meet during normal operation.

Starting horsepower is the momentary power needed to begin movement, which can be higher than the steady load but is not the ongoing requirement. Rated horsepower is the engine’s continuous output capability under standard testing—useful for knowing the machine’s upper limit, not the exact load at pumping. Maximum horsepower isn’t a standard specification for this context; it indicates an upper bound, not the ongoing driving requirement.