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Thread: Grizzly G0443 Cyclone Dust Collector Testing

  1. #16
    Join Date
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    Tippecanoe County, IN
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    Oh no! You want to know what the point of all this is. That's a great question but unfortunately a long and convoluted answer!

    Here's what it isn't. I'm not trying to help you improve your system, it sounds like it's good already. I'm not trying to be either a basher or fanboy of Grizzly (or Oneida or Clearvue or Jet or Laguna or …), they're all just trying to compete, satisfy their customers and make a buck.

    Curiosity is probably the biggest driver. The G0441/2/3 all seem to have performance curves that somewhat outperform their competitor's similarly labeled systems. I used the term “label” because the HP listed as a part of the name of the product just that; it is not a “rating” of the system but rather just the motor rating. What the fan actually demands can be much different.

    Most manufacturers “idiot proof” their systems for the hobbyist market. That is, the motor is sized to survive the most extreme hack job someone is likely to do to their system. That means there's margin left in normal operation. That is a prudent thing for the manufacturer to do, customer service is expensive.

    Clearvue, for one, goes the other way. They run the motor at it limit, or even slightly past, to squeeze the most performance they can out of single phase motor (5HP is a practical limit, single phase 7.5HP is rare).

    It appears that Grizzly does the same with the G0441/2/3. I don't know that for sure so that's why I'm so hungry for the data.

    Regarding your velocity questions, I think Bill said 1000CFM to collect the fine dust from a 15” radius sphere. That sphere has a surface area of a little over 8sqft so more like 120fpm velocity for that.

    To lift an object you need enough force to both overcome gravity and accelerate the object. The force depends upon the aerodynamic diameter (which depends upon shape) and the density of the object. So an Ebony ball would be a good worst case example.

    Also, the kinetic energy of a heavy chip load uses up some of the static pressure leaving less for airspeed. 4000fpm leaves some margin to account for that.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  2. #17
    Quote Originally Posted by David L Morse View Post
    I'm not trying to be either a basher or fanboy of Grizzly (or Oneida or Clearvue or Jet or Laguna or …), they're all just trying to compete, satisfy their customers and make a buck.
    Fair enough, if I come across as a fan boy, it's because I bought something closer to the Harbor Freight end of the scale, and it's giving me exactly what I was promised.

    And I agree Grizzly seems a bit overdriven. I really don't think that this is a "1 1/2 HP" motor, with it's current draw.

    If it's helpful I can ask my HVAC friend if I can borrow his pitot tube pressure guage. Before I do, I'd like to know exactly what tests you'd want to see run. I know from past experience that he cannot let me borrow it for long, so I usually get it, do the tests, and give it back in the same day.

    I can also run some more tests with the clamp meter if you're interested in the inrush current.

    I also might try reattaching the filter, though that's a half hour or so of manhandling, at least that's what it took last time.

  3. #18
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    I don't know if these have been posted before, but here is a video showing how to use a pitot tube to measure airflow in a system.


  4. #19
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    Quote Originally Posted by Andrew More View Post
    Fair enough, if I come across as a fan boy, it's because I bought something closer to the Harbor Freight end of the scale, and it's giving me exactly what I was promised.
    The HF is nowhere close to yours. It has a 10” fan, yours is 12”. All else being equal the HP draw of a fan varies with the cube of diameter. On that basis you could say that the HF has less than 60% of the fan performance of yours.

    Quote Originally Posted by Andrew More View Post
    And I agree Grizzly seems a bit overdriven. I really don't think that this is a "1 1/2 HP" motor, with it's current draw.
    Again, it's the load that determines the HP (and thus current) draw. The motor's HP rating tells you how long the motor will last at that load.

    Quote Originally Posted by Andrew More View Post
    If it's helpful I can ask my HVAC friend if I can borrow his pitot tube pressure guage. Before I do, I'd like to know exactly what tests you'd want to see run. I know from past experience that he cannot let me borrow it for long, so I usually get it, do the tests, and give it back in the same day.
    You don't really need the static tube to check pressure. A port on the wall will work. It needs to be flush on the inside and that's easy to do with PVC. For that a bulkhead barbed fitting is perfect. I've not done it with sheet metal. Thinking about it, I suppose I would start by drilling a small (1/8”?) hole in the duct. Cut off a piece of old bicycle inner tube, poke a hole in the center and push some 1/8” or so tubing through it. Then tape the rubber to the outside of the duct leaving the tubing hanging roughly tangent to it and sort of over the hole to keep the rubber from sealing it. I'm sure you can come up with something much better.

    If you want more accuracy then add some ports and make a piezometer ring.

    For additional tests it would be nice to have enough flow and pressure data to construct a fan curve. Besides becoming a hero to all of us data freaks you'll be able to compare to the Grizzly curve and see how much difference direct venting makes.

    If you also record motor current for the different flow rates you can use motor current as a quick way to measure flow. This is very useful if you make changes or add a drop some time in the future. Clamp on ammeters are fairly cheap and useful in a shop. No need to obtain an anemometer.

    Quote Originally Posted by Andrew More View Post
    I can also run some more tests with the clamp meter if you're interested in the inrush current.
    Unless the meter has a special peak reading mode it really won't be fast enough to measure the startup current. A good photo of the motor's nameplate might be more useful. If it's a proper NEMA tag it will list a locked rotor code. A quick lookup and some arithmetic gives the start current.

    Quote Originally Posted by Andrew More View Post
    I also might try reattaching the filter, though that's a half hour or so of manhandling, at least that's what it took last time.
    That would be a lot of work. A half hour to remove the filter, a couple hours to take enough data for a good fan curve and another half hour to go back to direct venting. Hardly seems worth it.

    But, you will have lots of data. Plot Grizzly's data and your with and without filter data on the same graph. Publish that and some photos of your test setup on a few woodworking forums for instant fame! Seriously, it's a lot of work and up to you how far you want to go with it but I don't think anyone has ever complained about there being too much real data on dust collectors.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  5. #20
    Quote Originally Posted by David L Morse View Post
    The HF is nowhere close to yours. It has a 10” fan, yours is 12”.
    No, not literally the HF DC, which is also a single stage, but rather I consider Grizzly to be akin to HF in terms of quality. Nobody has ever said Grizzly was the Mercedes of the wood working tool world.

    Quote Originally Posted by David L Morse View Post
    For additional tests it would be nice to have enough flow and pressure data to construct a fan curve. Besides becoming a hero to all of us data freaks you'll be able to compare to the Grizzly curve and see how much difference direct venting makes.
    So pressure, velocity, and amp draw.

    Quote Originally Posted by David L Morse View Post
    Unless the meter has a special peak reading mode it really won't be fast enough to measure the startup current. A good photo of the motor's nameplate might be more useful. If it's a proper NEMA tag it will list a locked rotor code. A quick lookup and some arithmetic gives the start current.
    If there is one, it's not readily accessible, I've looked. The clamp meter I have does max and min current, which should work.

  6. #21
    My attempt at a fan curve for the Grizzly G0443. This is without the filter installed, which is the reason why the last step is 2" SP, instead of 2.5", which is what grizzly starts with in theirs. I
    also have no idea why the velocity went down in the last step. All velocity was taken in the center of the duct with a hot wire anemometer, SP is with a pitot tube, amps with a clamp meter.

    Pressure gauge is a Fieldpiece SDMN6
    Clamp meter is a Fluke 33.
    Initial inrush current is ~73 amps.


    Velocity (fpm) Static Pressure (inches) Amps
    550 9.9 10
    2500 9.1 13.3
    3150 7.8 14.1
    3350 6.9 14.4
    3500 6.2 14.6
    3800 5.8 15.0
    4050 5.1 15.4
    4100 4.6 15.6
    4300 3.5 15.8
    4400 3.1 15.8
    5100 2.4 15.8
    5000 2.0 15.9
    Last edited by Andrew More; 07-24-2019 at 9:32 AM.

  7. #22
    Join Date
    Feb 2013
    Location
    Tippecanoe County, IN
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    Nice work Andrew. I've plotted both your data and Grizzly's on the same graph so we can compare them:
    G0443 Fan Curve.JPG

    Some notes on the above:

    1) I used you velocity numbers without a fudge factor. I did this for two reasons. First, after doing a power law curve fit to the traverse data you published earlier I got an average that's within about 3% of your centerline value. This is probably because of the skew in the velocity profile. Second, Grizzly doesn't give a lot of detail about their test procedure. Of course, neither do their competitors.

    2) The curve fits on the graph are a simple square law approximation. That's my preference because it makes the data so easy to use in calculations, and in this case the radial fan actually works this way in the basic mathematical model.

    Your measurements show slightly lower performance than Grizzly's. I know you were expecting better but it's certainly possible that your makeup air path has higher resistance than a new, unused filter. If you want to check that open a door or window and see if you can measure a difference.

    I also plotted motor current versus flow. You can used that in for future information if you want to check a change or new connection if you get a current meter after the test equipment goes back.
    G0443 Current.JPG

    I left out the last two current readings from the regression analysis. The values at the high flow rates should have a good fit to a straight line, these don't make sense to me so I didn't use them.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  8. #23
    Thanks David.

    Quote Originally Posted by David L Morse View Post
    Your measurements show slightly lower performance than Grizzly's. I know you were expecting better but it's certainly possible that your makeup air path has higher resistance than a new, unused filter. If you want to check that open a door or window and see if you can measure a difference.
    That didn't make a difference, but it did set me to thinking about it again. I believe the problem is the vent flap I have on the outlet. I jammed it open with a screw driver and did the all open test. This time I came back with a result of 5350 FPM, and likely at a lower SP. Since I've returned the meter, and I don't want to annoy my HVAC friend, I think I'm just going to leave it at that.

    There's also a slight bend to the pipe as it comes into the DC that might be effecting the results.

    IMG_20190724_174300.jpg IMG_20190724_174306.jpg


    Quote Originally Posted by David L Morse View Post
    I also plotted motor current versus flow. You can used that in for future information if you want to check a change or new connection if you get a current meter after the test equipment goes back. I left out the last two current readings from the regression analysis. The values at the high flow rates should have a good fit to a straight line, these don't make sense to me so I didn't use them.
    Yeah, I thought it was odd as well that it wasn't increasing, but couldn't see an obvious cause.

    So does that mean we can calculate the SP from the amp reading on the meter, even though the system has changed again?

  9. #24
    Just did a bit more testing. One of the things I put in when I was designing the system was a set of gates at each major branch.

    IMG_20190715_201624.jpg

    Here you can see the gates marked in red along each trunk.

    DCSetup.png

    There are essentially 4 branches, each leading off to a different tool cluster. When I put them in I thought they might be helpful, but I wasn't sure by how much. Just did some testing at the tools, and the difference is surprisingly about 1000 FPM.

    For this testing I had all the gates either opened (with the blast gates closed at the individual tools), or closed for all branches except the duct servicing the tool in question.

    Tool All Gates Open (FPM) All Gates Closed (FPM)
    Table Saw 2,700 3,500
    Sander 2,500 3,500
    SCMS 3,500 4,500

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