Quote Originally Posted by Chris Parks View Post
I would not buy a single phase dust extractor for a bet, it is an archaic and limited idea and should be done away with seeing we have cheap VFD's now available. I run my CV 1800 at 70hz and it rocks, has soft start and low current start requirements and if I choose to I can slow it down if needed. In Oz every CV I have sold or know of except for two is run by a VFD and adding remote control is a simple 5 minute exercise. Want to run an automatic blast gate system? then a VFD is your friend.

As for 90hz, would a normal three phase motor be happy at that speed? I limit to 70 hz after chatting to Bill Pentz and seeing two episodes of solid objects getting into the impeller housing and the damage caused. One only needed the wrapper around the impeller repaired and one had severe impeller damage and it was this possibility that caused BP to caution about going above 70hz. Another thing I think will be pertinent to impeller speed is what speed does the impeller efficiency fall off at.

The CV Max was invented to achieve at 50hz in countries outside the US the same airflow as the 1800 achieved at 60hz. That was pre VFD days and today the need might be re-assessed. It only became feasible to sell the CV in Oz because affordable VFD's became available but it took Oneida to recognise the advantages VFD's gave to dust extraction operation.
While I do think this could be a interesting project, I know that projects sit around in my shop for quite a while. Running the ductwork will be enough of a project to take on since right now I have a mobile unit I wheel around. I would prefer to just buy a plug and play unit for these reasons. If I had the time and found a decent used cyclone I would definitely consider a project like this. I did miss out on a 3 phase cyclone that sold at a auction near me for a measly 6$! That would have been a good candidate unfortunately I didn't see it in time.