Penn State vs. FWW

[Vince Heuring]

OK, I'm late in getting this posting out. The April issue of FWW compared 1-1/2 HP portable dust collectors, including the Penn State DC2V2. The reviewer, Michael Standish, tested them by measuring the static pressure increase as he increased the constriction on the air flow to simulate varying loads on the DC. He fitted the machines with a Wynn cartridge filter but claimed that there was little difference in performance between it and a cloth bag. The results were displayed as plots of static pressure in in. of water vs. air flow in cfm.

His plots were essentially linear. The results are "interesting."

StaticPressure FWW Penn State

1.5" 800 cfm 1200 cfm 4" 650 cfm 1050 cfm 8" 400 cfm* 600 cfm

In all three cases Penn State's flow rates are about 50% greater than Standish's.

Penn State calls the DC2V2 a "1250 cfm machine great for up to a medium-size shop." Standish puts it in the category of "machines [that] fall too quickly below the 800 cfm threshold for effective dust pickup."

Standish found the Delta 50-760 to be the best performing of the group, way superior to the Penn State.

I always thought of Penn State as one of the most conservative DC manufacturers when it came to quoting performance, so I wonder what's up with this.

BTW, I have a smaller Penn State unit and am pleased with its performance.

*Estimated.

[Toller]

My PS drew half the current they claimed; no surprise it moved less air than it claimed. Other DCs have measured have drawn nearly what was claimed; so no, PS is not conservative.

[charlie b]

It's the damn marketing department! BIGGER IS BETTER - so let's go with the biggest number- regardless of whether it means anything in the real world. Case in point -"horsepower". I've got a C&H compressor that says it's 5 hp - but can be run on a 20 amp, 120V circuit. Now if one horsepower in electrical units is 746 watts, then at 120 volts AC, it would draw 6.22 amps. A 5 hp electric motor would therefore have to draw 5 x 6.22 amps, or a tad over

31 amps. BUT it'll work on a 20 amp circuit! How is this possible? Wellllll - at start up, and only for a fraction of a second, it does draw 31+ amps - and then drops down to about 3 hp - if that - with a sustained current draw of under 20 amps. Now if you're an honest manufacturer you'd describe your motor as 3 hp. But some marketing guy at your competitor says "Hey, this thing draws 31 amps at start up - and that's FIVE HORSEPOWER! Let's slap a big 5 HP! label on our units and put that other guy out of business. Who'd buy a 3 hp unit if they can get a FIVE HORSEPOWER one for the same price?!"

Bill Pentz took an interest in dust collectors a while back - which turned into what borders on a compulsion - and really got into the subject - going so far as to buy the best measuring equiptment, setting up objective testing procedures and even went so far as to design a better cyclone - several of his innovations are now incorporated into a few cyclone vendors' systems. He's becoming the Underwriters Laboratory for dust collectors, with models being sent to him for testing and evaluation.

Google Bill Pentz and go through his Dust Collection site if you want to understand dust collection for woodworkers. More than you thought you'd ever want to know.

And while you're at it, google clear-vue

b