Why do rotary pumps have a limited speed range?

Rotary pumps have a limited speed range primarily due to their design and application limitations. This limitation arises from the physical mechanisms by which rotary pumps operate. The design of these pumps includes specific geometries and material choices that define their optimal operating conditions, including speed. As the speed increases, several factors can affect the pump's performance, such as fluid dynamics, pressure differences, and mechanical stresses.

High speeds can lead to increased wear and tear on rotating components, potentially leading to premature failure. Additionally, rotary pumps are often designed for particular applications where the flow rate and pressure requirements are within certain parameters. Operating outside these parameters can reduce efficiency and increase the risk of damage.

While there are concerns about maintenance at higher speeds and the potential for cavitation (which occurs when the local pressure in the fluid drops below its vapor pressure), these issues are secondary to the fundamental design constraints that determine the pump's operational speed range. Electric power is not inherently a limiting factor of speed for rotary pumps, as many pumps can be electrically powered and still function correctly within their designated speed limits.