Max. air flow rate
The highest speed of the air stream given out by the vacuum cleaner. The
higher this parameter, the stronger the thrust provided by the device, and the more efficiently it is able to pull or blow out debris particles from cracks and other hard-to-reach places (of course, if there is an appropriate operating mode — see above). At the same time, in most modern models, this figure exceeds 150 km/h — this is more than enough for work of small and medium complexity. Therefore, paying attention to a high flow rate makes sense only when choosing a powerful model for working in difficult conditions; we note that in the most “high-speed” vacuum cleaners, the indicators can exceed 400 km/h.
Max. engine speed
The highest speed at which the vacuum cleaner engine is able to operate in normal mode.
Theoretically, faster motors are capable of delivering more solid performance; however, in fact, these characteristics depend on so many different design features that the engine speed is practically lost against the background of these features. Therefore, this moment, in fact, is purely reference (and partly promotional — impressive rpm numbers can at first glance give the impression of high power and performance; but this impression is often deceptive).