dust collection WITHOUT BAGS.

[Devon Shannon]

Hi, I think this is my first post here, and I hate that it has to be about Dust collection. The topic seems a bit overdone. Still, I can't find the answer to my DC question. I read Bill Pentz's site a couple of years ago, (so no links are necessary), and decided exactly what I waned for a central DC in my shop. However, I couldn't afford it then, and still can't now. So, instead I want to get a 2HP DC and vent it outdoors.


1.)My question: will running a DC without bags cause the motor to over amp and burn up?

On several occasions I have read that the resistance created by the bags is important, and without the bags the motor could draw too many amps and burn up.

2.) If the answer to #1 is YES...
Given that I do not own any electrical testing devices, nor do I want to own these testing tools, how should I go about venting outside without stressing the motor?


If I left the bags on and just stuck the unit outside, It seems like I would not be taking full advantage of the situation...I would still have to empty chip bags/trashcans and clogged filters bags. The DC would run just like a DC indoors and no better..

I have been looking forever for a thread on this, so any thoughts or links would be much appreciated!
thanks in advance,

Devon
Seattle WW

[Tom Veatch]

...
1.)My question: will running a DC without bags cause the motor to over amp and burn up? ...

With no more information that what's given, it's impossible to definitively answer either yes or no. There's simply too many unknowns.

If the system has a 2HP motor and the impeller is sized such that it won't absorb more than 2HP running unrestricted, then the answer is, "No, you won't burn up the motor running without bags".

But, if the housed impeller can absorb more HP than the motor is rated to produce, the system depends on restrictions in the flow to keep the work done by the impeller below that which can be produced by the fully loaded motor. In that case, whether or not there's enough flow restriction in the ducting, without the contribution of the filter bags, is indeterminate.

With my specific system, a cyclone, my on-site testing has shown that it's not a problem and I do, in fact, run without filters. My gut feeling is that it's not a problem in general. But, I have no experience or analysis to justify that feeling and the circumstances of my particular installation are not the same as what your's will be, nor can my results be used to predict your's. If you're adamant about not obtaining a clamp on ammeter, even temporarily, to do a simple check, I suggest querying the customer service folks for the system(s) you're considering. They should be able to give you a more definitive answer, but, I predict they'll take a CYA position and say you have to use the bags.

[Bob C Thomas]

I duct my dust outside my shed through two 44 gallon drums which collect everyhthing except the superfines. I left the bad on to see what it collects, which is virtually nil.

A friend copied my setup without the bags on the blower and he has more suction than me and no problems at all with his blower motor.

[Devon Shannon]

With no more information that what's given, it's impossible to definitively answer either yes or no. There's simply too many unknowns......

Thank you Tom. That was a very thoughtful reply to my question, and you have been most helpful. I think I will look into temporary obtaining an ameter and do the test.

[Dan Friedrichs]

Tom gave you the engineer's answer So I'll give the practical one (or at least what I think is practical): Go for it.

A number of posters here do exactly what you suggest, and there have never been any reports of motors burning up. I suppose it is technically possible, but unlikely. You'll probably vent outside into a chip box, which will provide some head to the blower, anyways.

If you want to be absolutely sure, pick up a $4 multi-meter from HF and measure the AC current flowing into the motor with and without bags (and with the inlet fully open). If it's not over the motor's FLA rating, you'll be fine. But again, the probability that this would pose a problem seems awfully low...

[David Hostetler]

Just FWIW, a low budget system can be put together without blowing your fines outdoors. That would be the HF #97869 2HP Dust Collector, fitted with a Wynn 35a cartridge filter. Get the HF DC on sale with the 20% off coupon, and you can get the whole shebang together for under $300.00

[Augusto Orosco]

Hi Devon,

I posted a similar question before and got many useful replies:

http://www.sawmillcreek.org/showthread.php?t=107980

Hope it helps!

[Rob Russell]

Tom gave you the engineer's answer If you want to be absolutely sure, pick up a $4 multi-meter from HF and measure the AC current flowing into the motor with and without bags (and with the inlet fully open). If it's not over the motor's FLA rating, you'll be fine. But again, the probability that this would pose a problem seems awfully low...

The only way a $4 multimeter is going to measure the current is if it's inline with the circuit. I'll bet you'd have a problem running that much current through the little leads you'd get with such a multimeter.

I like Tom's suggestion of borrowing a clamp-on ammeter. If you can't borrow one, buy a good condition used on on Ebay and then resell it when you're done with it.

[Dan Friedrichs]

The only way a $4 multimeter is going to measure the current is if it's inline with the circuit. I'll bet you'd have a problem running that much current through the little leads you'd get with such a multimeter.

I like Tom's suggestion of borrowing a clamp-on ammeter. If you can't borrow one, buy a good condition used on on Ebay and then resell it when you're done with it.

http://www.harborfreight.com/cpi/cta...emnumber=95652

[David Giles]

Based on a three year operating history, the answer is no.

[Steve Clardy]

This is a 4hp 4 bag unit I modified and sat outside.

tn_newblower installed.jpg

Built a stand and sat it on a concrete pad.
Motor cover is not shown as I wasn't quite down when I took the picture.
Its been 4-5 years now I guess.


Motor is going strong. I don't believe you will have a problem.

[Devon Shannon]

Thank you, to everyone, who took the time to help me with my question. I don't personally know a single woodworker, so I am very grateful for this forum and other WW forums. You have all been most helpful.

Devon
I build furniture in a Barn near Seattle

[Frank Hagan]

I've always heard its restriction on the suction side that's needed, i.e., you shouldn't run a DC without any ducting attached (or a flex hose for the portable guys).