Very smart and sensible suggestion, indeed. The real question is, - are they produced / manufactured here in USA / Japan or Europe? So far, I saw only constant speed varieties from guys like Soler / Fantech, Greenheck..etc. I flatly refuse to buy anything from China, especially mechanical devices requiring high quality bearings and other hi quality important components.
Dwyer Instruments will help you. This may not be an off the shelf item (It may be, don't know) I will look into this deeper. The "control section" area of this forum may be a better place to get some help. But, like I said, I'll look around for you.
Dwyer Instruments will help you. This may not be an off the shelf item (It may be, don't know) I have installed many Greenheck fans, nice stuff.
I checked the Dwyer Instruments, Inc. WEB site, - they are specializing mostly in flow control & other related categories. I didn't see any fans on their site. Maybe they can refer me to proper mnufactures if I call them