Johan_Ha:
I thought of attaching a vacuum cleaner to an old reed organ. This has been done before and there needs to be a device inbetween, which lowers the underpressure. But my old vacuum cleaner has a speed regulator. Anyone know how I could hack the speed regulator? There is a slide for the control and it feels like a potentiometer, but some pages say the vacuum has five speeds.
Anyway, I'm looking for solutions for reducing the power, either by hacking into the regulator or replacing it with something else. I think the AC motor has some lowest speed, where it still runs ok without risk of stalling and causing some unwanted electric problems. At that speed it would also be very quiet, which of course is a bonus for my reed organ project.
The vacuum I intend to use is an Electrolux Oxygen and the motor looks like this:
Vacuum Cleaner Complete Motor - 1131503052 | ElectroluxOr are these usually DC motors and the speed regulator includes a rectifier?
I think I would got with trying to mod the regulator to set the speed (if you post a picture of the actual PCB might even be able to help! 
). but why post here? are you planning to an arduino with it...?