Yet another motor question

[Mike Cruz]

Okay, I got a small/medium dust collector on CL. Its a Delta DC-610, I believe. It has a 3/4 HP motor and moves 610 cubic feet a minute and a 4 inch port. I would assume (yeah, I know what happens when you do that) that it moves 610 cubic feet of air WITHOUT a hose.

Now, when you add, say a 20 foot hose, I would also assume that it may only move about, say 500 feet a minute. If I am wrong at this point, then I may be flawed for the rest of this...

What would a more powerful motor on this dust collector do? I would imagine that a more powerful motor with the same rotation rate (and the same impeller) wouldn't move more air WITHOUT a hose, but would it maybe keep the air feed rate up near/at 610 even with a 20 foot hose? Or is phsyics physics and you CAN'T keep the air flow up...no matter what you do?

I wonder because of two reasons:

A) I have seen Grizzly DC's that are the same size with different size motors (1, 1.5, and 2 HP).

B) I will have some relatively long runs on this small dust collector (longer that the 6 foot hose that came with it) and am CURIOUS as to whether it would be in my best interest to CONSIDER changing the motor IF I found the perfect motor for a steal.

I am 75% sure I WON'T be changing out the motor simply for an upgrade, but am curious about this. The unit is about 8-10 years old and when I got it the impellor was broken (NOT disclosed by the seller...fixed but missing two vanes). I put a new one in and it runs great...for now...

Thanks for your input.

[Rod Sheridan]

Hi Mike, the rotational speed of an induction motor changes very little from no load to full load.

Changing the motor power wouldn't change the fan speed, so no changes in fan performance.

When I measured my old bag type collector, it had about 50% of claimed airflow with 10 feet of 4" pipe, the only way I got claimed airflow was with no duct and the bags removed.

I then purchased an Oneida cyclone which did deliver claimed airflow, and made my shop esentially dust free.

Regards, Rod.

[Mike Cruz]

So then why have two DC's that are essentially the same with two (or three) different motors (i.e. Grizzly having the large single bag version with 1, 1.5 and 2 HP motors)?

Another way of asking that would be why run a 2 HP motor on a machine that will do the same job with a 1 HP motor?

What, if any, difference would there be/would I notice if doubling the HP of my DC from 3/4 to 1.5?

[Myk Rian]

So then why have two DC's that are essentially the same with two (or three) different motors (i.e. Grizzly having the large single bag version with 1, 1.5 and 2 HP motors)?

Another way of asking that would be why run a 2 HP motor on a machine that will do the same job with a 1 HP motor?

What, if any, difference would there be/would I notice if doubling the HP of my DC from 3/4 to 1.5?

The difference may be in the fan design. It would take more hp to turn a more aggressive set of blades.

[Kyle Iwamoto]

The dust collector you bought should have the practical or "reccommended" limits of hose length in the manual. The different HP of the same looking DC units probably (I say probably since I have to assume this also) have different impellers, or they may be slightly bigger and just LOOK the same. Bottom line is, if you upgrade your motor, but everything else stays the same, you'll get very little increase in airflow, if any at all. If you look at flow through a pipe or duct, a 1/4" increase in diameter is a HUGE change in airflow. The DC units may indeed look the same but be slightly bigger and can pass more air. At that point, a bigger HP motor WILL move more air.

Just my .02. I'm not a flow engineer.

[Mike Cruz]

Thank, guys, I think you answered my question.

So to reitterate what you all have said, it would be significantly worth my money, time, and energy to invenst $200 for a motor and install it into a $100 dust collector because it will massively increase my dust collecting capabilites. Sweet, thanks for the advice and direction.

Really, though, thanks for explaining it. I apparently had the physics of it wrong. When Rod said his DC had about 50% of claimed airflow with 10 feet of 4" pipe, I thought I might be on the right track...that increasing the HP would keep the air flow up at the end of a long pipe. But now I think I understand it better.

[Kyle Iwamoto]

Essentially, you get what you pay for. See if you can swing the Delta 50-760. $450 or so. 1.5 horse motor, it runs on 110V. Most important, it has a 1 micron bag, and that keeps all but the finest dust out of the air. It's also pretty quiet. Not noiseless, but less than my saw. Don't bother if the DC has a 30 micron filter. May as well use a fan.

[Mike Cruz]

Thanks for the input. I guess I should have mentioned that this is a second DC in my shop. I needed one to supply my band saw, drum sander, and disc sander. I have a 2 HP Grizzly for my table saw, jointer, floor sweep, and hopefully soon planer...if I ever find a deal on one. The Delta needed to be small to fit between the other equipment. I wanted but could afford (spacewise) to get a full size collector there. Actually, I found one for a great deal, about $100, that equaled my Grizzly, but was just too big. Thanks for the input, though. Oh, and I also have a Jet air filtration system, and a heavy duty exhaust fan (for whether I have the doors and windows open or not).

[Kyle Iwamoto]

Why don't you just get blast gates and use the big Griz? you seldom will run more than 2 machines at once, just shut off flow to the not in use machines and the 2 horse Griz should hack the load all by itself. Certainly cheaper than buying more gear. But then who can resist MORE GEAR?

[Mike Cruz]

Hehe, yeah, I am certainly guilty of always wanting more gear. But I am really trying to avoid running ducts overhead and everywhere. I have the Grizzly in the middle of the planer (spot for the planer), jointer, table saw, and floor sweep. The band saw, and two sanders are against a wall. It seemed like a good idea at the time...it ought to work well.