Replies

1. 
   nicobie | Oct 06, 2004 03:24am | #1

   My $119 HF 2hp DC has a 10.5" impeller and draws around 10 amps with no ducting.

   Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.

   Ronald Reagan, August 15, 1986

2. 
   Kent_F | Oct 06, 2004 04:37am | #2

   Penn State Industries DC2000 2 HP DC: 12" curved fin impeller.

3. 
   WayneL5 | Oct 07, 2004 01:03am | #3

   I don't know all the answers, but I can tell you something.  Radial fins are cheaper and more rugged when the air has particulates in it.  They are often used in material handling fans.  But, they are less efficient, that is, they draw more horsepower to move a given amount of air compared to other designs.

   A fan wheel takes a certain amount of horsepower to spin it at a given speed.  The motor must be capable of providing at least that much power.  Usually in fan design the closest standard horsepower motor at or above the fan requirements is selected.  If you put a very much larger horsepower motor it won't run any better, but will use more electricity.

   Motors vary a lot in efficiency.  Cheap motors can be only 65% efficient, premium efficiency motors can be around 93%.  It's likely that the cheapest motors would be used by dust collector manufacturers, both for initial cost and because the cost of the more efficient motor would never be earned back in energy savings on a machine that might only be used a few hours a week.  If someone had a commercial shop using a dust collector 40 hours per week or so they would be wise to do the math to see if a high-efficiency motor would pay back in a reasonable length of time.