What is the pump design called if it has the impeller mounted on a separate shaft, which is connected to the motor with a coupling?

• A. End-suction
• B. Frame mounted
• C. Vertical turbine
• D. Split-case

Answer: (B)

Frame-mounted refers to a pump design where the impeller sits on its own shaft inside the pump, and that pump shaft is connected to the motor on a separate frame by a coupling. This arrangement means the motor does not directly drive the pump's shaft; instead, the motor’s rotation is transmitted through the coupling to the pump shaft, allowing some flexibility for alignment and easier maintenance. This setup is distinct from close-coupled or direct-drive designs where the motor and pump are on the same shaft or integrated together.

Understanding the other terms helps: end-suction describes where the fluid enters the pump, not how the pump is driven; vertical turbine refers to a vertical, multi-stage pump arrangement; and split-case describes the geometry of the pump casing. The described scenario—impeller on a separate shaft connected to the motor by a coupling—fits the frame-mounted arrangement.