Shopsmith Forums

To answer a number of questions asked and comments plus adding one more tidbit of information:
1. The 150 CFM maximum rating is from the Oneida web site (the recommended airflow is from 50 to 150 cfm).

2. I sent Oneida an email this morning and asked specifically 'would the DC-3300's 330 cfm be too much for the Dust Deputy (DD). Their reply basically was 'No'. They said anything less than 3 HP should be fine. Not quite sure how to interpret that! Certainly very encouraging for using a DD with the DC-3300.

3. Some one asked how you would hook up the DD to DC-3300. Simple - run a hose from the regular air intake on the DC-3300 over to the top port on the DD and then connect the side port on the DD to the machine you are using.

Bob Groh

dusty wrote:

ChrisNeilan wrote:

bobgroh wrote:Dusty, the one thing that is not known is how the system resistance of the Dust Deputy (DD) responds to increased airflow. It could be that the DD has a non-linear response, e.g. the restriction in the DD dramatically increases over a certain flow rate. That would also have an impact on the DC-3300 and, if one had the flow rate characteristics for both systems, you could (to some degree) 'guesstimate' how things are going to even out. The DD is only specified up to 150 CFM so who knows? JPG is using one so a real-world test is underway! I will probably give it a try when I get things up and running.

Bob Groh

Where do you find the specification of 150 CFM for a dust deputy? I have been using one for over a year and my shop vac puts out much more that that. Heck, my bathroom vent puts out over twice that!

Interesting. How do you determine the CFM capacity of your Shop Vac. I have a 10 gallon version and I'd like to determine what mine is. "The hand on the end of the hose test" indicates that mine is sucking but how much. It sure is not as powerful as my DC3300.

The Dust Devil is recommended for use with no less than a 150 CFM air flow (the rating for the vacuum).

Dusty, just guesstimating based upon when I use my shopvac as a blower, it seems to move more air than my Ryobi leaf blower which is rated at 200 CFM.. I admit, no science involved to prove it...

Don't have the shopsmith dust collector but I have two of the dust deputy's.

One is attached to an older shopvac the other to a very nice large shopvac and that one is spec's better then the shopsmith system.

They both work fine. There is perhaps some loss on the larger system but not such that I notice. Measurements would be needed as I see no difference. If I can see the difference then to me it matters not. Of course if I used it differently it might show up. At this point I don't see a reason to worry one way or the other, if it works it works.........

Crazy peak rated HP of 6.5 on the larger one but I doubt that means much. So the HP numbers they gave you should mean it will not work right??? Actual HP is going to be much less but they don't give that. I'm guess it is under 3??

Ed

dusty wrote:

JPG wrote:I suggest waiting until after you try the dust deputy with the dc3300 to determine course of action. I use it that way.

Would you please post a picture of this setup (Dust Deputy attached to a DC3300). In my minds eye that is just two dust collection containers in series. Which one ends up with all the dust? What am I missing?

Do you really need a pix?

Short hose from the DD to the DC3300(single port, others plugged).

Long hose input to the DD.

The DD catches almost all.

DC3300 bag gets very little.

Filter bag gets the remaining fine stuff.

Yes it loads the DC3300 slightly.

I believe the cfm is decreased slightly.

It keeps up with the jointer.

I have not tried it with the planer(need chute upgrade).

DD mounted to a shop vac base(barrel).

reible wrote:Don't have the shopsmith dust collector but I have two of the dust deputy's.

One is attached to an older shopvac the other to a very nice large shopvac and that one is spec's better then the shopsmith system.

They both work fine. There is perhaps some loss on the larger system but not such that I notice. Measurements would be needed as I see no difference. If I can see the difference then to me it matters not. Of course if I used it differently it might show up. At this point I don't see a reason to worry one way or the other, if it works it works.........

Crazy peak rated HP of 6.5 on the larger one but I doubt that means much. So the HP numbers they gave you should mean it will not work right??? Actual HP is going to be much less but they don't give that. I'm guess it is under 3??

Ed

All peak HP ratings are just marketing hype. They mean nothing. They are based on the motor inrush current. If you use the SS motor's inrush current (Approx. 45 Amps) the peak HP is almost 5 HP.

jsburger wrote:

reible wrote:Don't have the shopsmith dust collector but I have two of the dust deputy's.

One is attached to an older shopvac the other to a very nice large shopvac and that one is spec's better then the shopsmith system.

They both work fine. There is perhaps some loss on the larger system but not such that I notice. Measurements would be needed as I see no difference. If I can see the difference then to me it matters not. Of course if I used it differently it might show up. At this point I don't see a reason to worry one way or the other, if it works it works.........

Crazy peak rated HP of 6.5 on the larger one but I doubt that means much. So the HP numbers they gave you should mean it will not work right??? Actual HP is going to be much less but they don't give that. I'm guess it is under 3??

Ed

All peak HP ratings are just marketing hype. They mean nothing. They are based on the motor inrush current. If you use the SS motor's inrush current (Approx. 45 Amps) the peak HP is almost 5 HP.

Peak Power is merely √2 times the 'true' (RMS) power.

Yes it is marketing BS.

For example at 60 Hz, the instantaneous value peaks 120 times/sec and is zero as often. 120V AC has a peak value of ± 169.7 v and a minimum of 0.

120v is the true(RMS) value.

A large motor driving an inefficient air mover will merely be an expensive room heater.

Now this is getting fun! Heck, those marketing guys really oughta enlist an engineer if they want to stretch the truth all the way up to the hairy edge of the breaking point!

John, you have an excellent point re. the inrush current. It never occurred to me that we could just talk about motor input power! The "locked rotor" inrush I measured on my Mark V was 54 Arms. Now this dragged the voltage down almost 15Vrms, but that's only because I had it plugged into a wimpy 20A, 12AWG circuit. On a proper 50A circuit with 6AWG wire, we would have at least 115Vrms at our disposal. BTW, if anyone is having trouble sleeping tonight, you can fix that by viewing my actual measurements over at this old thread.

Which thread shows (if you zoom in far enough) that the peak inrush current is in phase with the line voltage, implying that it is limited almost entirely by the motor winding resistance. So the peak instantaneous input power is 2 * 54Arms * 115Vrms = 12420 Watts. Or even a bit more, since the lower voltage drop of the 6AWG wire would also mean proportionally more motor current. So at 746 Watts per horsepower, we can "honestly" rate my Mark V motor at more than 16 hp of peak input power!

"But wait", you say. "I only care about output power!"

Ok, we can play that game too. For starters, we'll use the official 1-1/8 hp continuous-power rating of the Mark V motor. But mind you, that is an average power rating. It can deliver much more power for a few seconds at a time. And it has a lot of inertia and kinetic energy, just like a flywheel, and so can deliver immense amounts of power for very brief periods. But we'll be "reasonable", and simply assume that we are going to cut 1/8" thick stock with a two-tooth, 8" diameter dado chipper. Which teeth travel through a circumference of about 25" per revolution, while cutting off only two 1/8" chips per revolution, or 1/4" total per revolution. So with an average power of 1-1/8 hp at our disposal, our available peak output power to cut those chips is 1.125 * (25 / 0.25) = 112.5 hp. Honest!

But totally misleading, of course. Given the wild "developed power" claims commonly used by the marketing folks, the best comparison strategy is to simply ignore them. Instead, just look at the motor amperage rating, remembering that a 240V motor only needs half the current of a 120V motor to make the same power. The only other factors involved are motor efficiency and power factor, and those don't vary all that much among standard motors of similar size. (If a 3-phase motor, multiply motor current by 1.73 before comparing to single-phase motor current.)

For one last reality check, any AC motor that runs on a 15A, 120V circuit is going to have a maximum honest continuous output power of 1.5 hp or less, after efficiency and power-factor adjustments. Anything higher will pop your circuit breaker.

1.73?

NOPE! It is what it is. The DC3300 does a reasonable job of collecting the dust. This is especially true if connected to only one active device at a time. I am all through trying to make it into something that it is not. I may try some new hose and better ways of routing it and attaching it to the setup but that is all. I will just have to be content with what I have.

What you have already seen is all there is to tell.

JPG wrote:1.73?

For 3-phase power,

P = SQRT(3) × V_line × i_line × cos(theta)