CV1800 and CVMAX Fan Curve

cvcsupport

cvcsupport

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Attached is a copy of the CV1800 and CVMAX fan curve.

If there are any questions regarding this fan curve, please post on this same thread.
 

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The fan curves appear to be in error. The CV-1800 outperforms the CV MAX over much of the range.?! Is this a mix of old and new measurements?
bababrown
 
I am curious about this as well.

It seems that the CVMAX only outperforms the CV1800 with an 8" line, and then only up to an SP of 6 or so. You have to consider they use the same motor and just use different sized components, so I guess it makes sense the larger size parts could harm performance in some ways.

This does seem counter intuitive though.

I recently ordered a CVMAX that has not yet shipped. This chart has me re thinking my decision to go with the MAX over the 1800.

It seems I might actually be losing performance in my application since my main tool is a CU300 with somewhat restrictive internal plumbing. I thought the CVMAX would be a better performer than I needed, with extra power to spare. I had not even considered that it could perform worse at higher SPs.

Can anybody advise me?
 
Compare the CV-1800 curve with 6" pipe with that for the CV-MAX with 6" pipe. The CV-1800 wins hands down. The larger impeller of the MAX should use more of the horsepower. The fan laws say it should produce roughly 6% more airflow, 12% more pressure, and 18% more motor power. And that's just the impeller change. The larger cyclone inlet should reduce the loss in the cyclone. So I have to believe the data is in error. I'm not sniping; the data doesn't help sell the MAX.
bababrown
 
The CVMAX is designed for an 8" trunk line having two 6" open gates. Due to restrictions in the fan curve testing parameters, the results do not reflect the appropriate data for that design.
 
I am building out my duct system and also using the bill pentz calculator to calculate total SP loss in my system One question I have is why this fan curve for the 1800 starts at 5 inches of SP does that mean before I even start adding piping I am at that level of static pressure?

Thanks and cant wait for a dust free garage work environment.
 
cvcsupport said:
Attached is a copy of the CV1800 and CVMAX fan curve.

If there are any questions regarding this fan curve, please post on this same thread.
Click to expand...

In the "Misc. Losses" part of Bill Pentz's static pressure drop calculator spreadsheet (row 125&126, zipped here or available for download from Bill's site), Bill says:

If you are looking at a cyclone DC whose fan curve says something like "Static Pressure at Cyclone Inlet", then the four Misc Losses above are already accounted for and should be left blank or set to zero.

I notice that rows 122 through 123 specifically give values for Bill's design & the Wynn filters (600 ft^2).

Since your fan curve does not say "Static Pressure at Cyclone Inlet", should I assume that these values were not accounted for in this fan curve?

It's no problem either way; it just affects my sizing and layout.

Jim in Alaska
 

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Kevinmc said:
I am building out my duct system and also using the bill pentz calculator to calculate total SP loss in my system One question I have is why this fan curve for the 1800 starts at 5 inches of SP does that mean before I even start adding piping I am at that level of static pressure?

Thanks and cant wait for a dust free garage work environment.
Click to expand...

Hi Kevin,

Our questions are related and I suspect lines 120-125 explain the curve, since 2.25" for the cyclone + 0.2" for the Wynn filters + 2 for filter seasoning puts us in that vicinity, but we'll need to wait for the experts to respond. :)
 
The following is a reply from Bill Pentz:

Our cyclone adds only 2.25" of resistance. Our low resistance coupled with our oversized impeller lets us pull a real 1200 CFM through a 6" pipe. You should have plenty of capacity with our cyclone and blower to handle a shop with up to 12" of resistance. If my static calculator comes up with a higher than 12" resistance, you should probably use a 7" or 8" main or strategically place blast gates to drop the resistance in order to get the 1000+ CFM we know we need for good fine dust collection.
 
Why does the 6" test better than the 8"? Why does the CV1800 outperform the CVMax? Is the air velocity too slow for an 8"? Would a 7" outperform both producing 3750fpm at 1200cfm vs. 5100fpm for 6" and a too slow 2800fpm for the 8"? It seems the air flow has to be under 900cfm before the velocity is in the 4500fpm upper range specified for wood working.
 
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