All vacuums do. When you look at the ratings plate and it says "1000w nom / 1200w max" or something to that effect, thats what that means. Basically, if you put your hand over the end of the hose, the motor increases in sound and the suction increases - that's full power. But vacuums don't run at the constant maximum all the time - the motor would overheat otherwise. I'm probably not explaining this all too well...maybe somebody else would be able to explain it better than I can, but I know what I mean in my head lol
