Sorry to hear the weather's put a damper on your trussing...
But, thanks for starting the new thread. Ken can participate here, in addition to his Onieda thread...
A squirrel cage fan is NOT NOT NOT what you want. They can move some air, but not with any sort of pressure! They BLOW in HVAC systems, but wouldn't be able to SUCK in a DC application...and they certainly couldn't take the abuse of material going THROUGH the fan. That's what the "material handling" in the term comes from. The material passes right through the fan.
Here's a link to Cincinnatti Fan, the company that makes the blower I picked up from Craigslist. (I have a 7.5hp PB15, for what it's worth). Have a read through some of the introductory information, and look at the different sorts of fans they offer. They do a far better job of explaining the requirements for a DC blower and system than I ever could!
Also, here's a link to a material handling blower that's currently on eBay...link... Although, I think that's a little pricey for what it is.
In general, I think you'd be better off watching Craigslist, or some other locally based venue. I say that because shipping can become an issue. My blower weighs somewhere in the vicinity of 300 pounds!!!!
As for the space you have overhead...a few things to keep in mind...
I was originally going to place my blower (and phase converter) up in my attic...but was quickly dissuaded when I learned the nightmare harmonic vibrations they'd create! Weight is also something to keep in mind as noted above.
As for the drop-box up in your overhead...you'd have to come up with a creative way of emptying it....
My personal opinion is that a bumpout would be your best bet. Recall that shed I put out back? It keeps the noise to an absolute minimum...(I only hear the rushing of air..no motor sounds). It also contains any sawdust mess OUTSIDE!
The other thing to keep in mind is tod's advice of determing what you need, port sizes and CFM requirements, then design a system to your needs. Figure out what you need in terms of air movement, then figure out what components you'd need to meet those needs. Designing it the other way around is a real risk.
Ok, I think I covered your initial volley. I'm sure tod will add to my response when he gets to the shop in the AM.
- Marty -
When you earnestly believe you can compensate for a lack of skill by doubling your efforts, there’s no end to what you can’t do…