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  1. #16
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    Feb 2012
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    Gentlemen, the Gregory Machinery 1900 (Pro Deluxe?) DE (approx. $600.00) does NOT have a 14 inch impellor, only 12 inch. I checked it today and informed the GM Management who immediately amended their advertising literature. I don't know if the other specs on this machine are also incorrect or whether the specs on the Woodman DE 1900 are correct/incorrect.
    Regrds Geoff

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  3. #17
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    Apr 2019
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    NSW
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    so i've done a bit of reading and taking in some of bobl's advice about what i should have or be doing for better dust extraction.

    I bought the cheapest 3hp (claimed) dust extractor i could find that wasn't 2nd hand. ended up with the Bayer 3hp machine for $450 from sydney tools
    Sydney Tools

    • Motor power: 2.2kW (3HP)
    • Inlet size: 3 x 100mm
    • Air flow: 3900m³/h (2200CFM)
    • Capacity: 307L
    • Filter: 5 micron
    • Rated voltage: 240V
    • Rated frequency: 50Hz
    • Rated input power: 240W, Class I


    i knew i was going to have to tweak the machine to get the most out of it which is why i bought the cheap one. there is such a surprising difference between my crappy 1hp model and this one. especially with the 1hp bag being 3/4 full, i've pretty much lost 3/4 of my suction. but the new big fella you can actually feel like suction forcefully pulling a bit piece of wood onto the intake.





    so the fan intake comes with a 3 prong dongle but under that the actual grill/hole is approx 150mm. its about 145mm at the actual grill but it is on a taper. so i may need to make a custom wood cover plate with a radius to mount the 150mm PVC pipe i plan on using.




    what is going to let me down is the exhaust side of the fan
    it is 150mm x 115mm giving me a surface area of 165cm2
    the intake ducting is 150mm so surface area of 176cm2

    so i'm already on the back foot in terms of getting full flow out of the fan with out making totally custom exhaust pipe work. that and you add on leakages and the bags and it is never going to be perfect.





    so a brief list of things i intend on doing:

    do some testing on the motor current draw before and after and mods
    Seeing if the carbatec pleated filters will fit onto this machine (they have a VERY similar looking model)
    replacing the terribly fitting gaskets with ones that actually fit and seal
    possibly install its own 15amp dedicated circuit to run it off
    moving the unit further under the house and try boxing it in
    run the ducting


    This is going to be quite a slow process to get it all in and running right. it does make it a bit harder with out any air testing equipment to know if it is worth it.

  4. #18
    Join Date
    Feb 2006
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    Perth
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    Quote Originally Posted by havabeer69 View Post
    so the fan intake comes with a 3 prong dongle but under that the actual grill/hole is approx 150mm. its about 145mm at the actual grill but it is on a taper. so i may need to make a custom wood cover plate with a radius to mount the 150mm PVC pipe i plan on using.
    I would completely remove the existing bolted on front plate a make a new one from sheet metal or MDF.
    For sheet metal I used a piece of steel plate from an old white goods appliance cabinet

    You can use the same ideas for the inlet as for the 2HP DC mod
    The Generic 2HP DC

    Instead of 32 mm melamine like I used for a flange you can cut two squares of 18 mm thick MDF and glue them together.
    Cut a 154 mm diam hole in middle of the MDF sandwich
    Rout as large a round over as you can on the inside edge of the hole in the MDF - this creates an inverted BMH
    Now measure the size of the routed hole at the outer edge of the BMH and cut the hole in the cover plate to this size.

    Rout a shallow (6mm) rebate onto the outside edge of the 154 mm hole for a stub (~200 mm long) of 150 mm diameter PVC pipe to fit/glue into.
    Now bolt the flange onto the cover plate.

    what is going to let me down is the exhaust side of the fan
    it is 150mm x 115mm giving me a surface area of 165cm2
    the intake ducting is 150mm so surface area of 176cm2

    It's actually a bit worse as the 150mm pipe is 154mm ID so the area is 186cm^2 but short of rebuilding the Impeller housing there's not much I would not be too concerned as there will be many other restrictions in your system that will be

    so i'm already on the back foot in terms of getting full flow out of the fan with out making totally custom exhaust pipe work. that and you add on leakages and the bags and it is never going to be perfect.
    Sure but don't forget you only paid $450 for it.

    The only real advantage of this DC over a 2HP is the fact that it has two bags - which is itself worth having.
    And being a 3HP motor it should cohoe with any extra heating for much longer.

  5. #19
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    Apr 2019
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    thanks for the info bob, i did plan on probably having to build a new intake plate, need to rummage under the house and see what scrap i might have.

    another question i might ask is there a rule of thumb about max ducting run length? i know short as possible is what i need to do. But i could be looking at around 12 meters of ducting to the furthest port on the way i plan to run the pipe. is there any rough guide as to at what length of ducting you will start to really notice the losses? i understand this is probably a machine specific question which is why "shortest is best" is mainly the answer.

  6. #20
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    Feb 2006
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    Perth
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    Quote Originally Posted by havabeer69 View Post
    thanks for the info bob, i did plan on probably having to build a new intake plate, need to rummage under the house and see what scrap i might have. another question i might ask is there a rule of thumb about max ducting run length? i know short as possible is what i need to do.
    That's it.

    The flow generated by your DC using 150mm ducting is not that high to start with so the loss of flow will be relatively low.
    It's often accompanying twists and turns of the ducting pathway (hence requiring more junctions) on long ducting runs that will effect the flow more than just the sheer length of the ducting.

    But I could be looking at around 12 meters of ducting to the furthest port on the way i plan to run the pipe. is there any rough guide as to at what length of ducting you will start to really notice the losses? i understand this is probably a machine specific question which is why "shortest is best" is mainly the answer.
    If you have to run 12m then you probably have no choice. Try to get the 12m as straight as possible with fewest junctions.

    The underside of my TS is on the end of an about 12m run, but worst still are the 4 right angle bends in the ducting to get it to that point.

    Sometimes there are even benefits to going a longer that are worth having. The choices I had for my TS cabinet extraction were; ducting across the floor (no way), ducting coming down from OH which would have been in the way, or ducting under floor, completely out of way but longer and more junctions. This is offset by the high flow OH TS Guard Ducting which does not get in the way as that does not go past the level of the TS table and is only 5m long.

  7. #21
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    Apr 2019
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    I did a very small amount of basic elect testing.

    So it'll slurp down around 5 - 22 amps on start up
    VideoCapture_20200229-211351.jpg

    It then simmers down to around 5.8amps with the intake splitter off
    VideoCapture_20200229-211400.jpg

    Intake splitter on and 2 ports covered was 6amp
    VideoCapture_20200229-211547.jpg

  8. #22
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    Quote Originally Posted by havabeer69 View Post
    I did a very small amount of basic elect testing.
    So it'll slurp down around 5 - 22 amps on start up
    It then simmers down to around 5.8amps with the intake splitter off
    Intake splitter on and 2 ports covered was 6amp
    Are you sure you have this the right way around? as the more a DC is restricted the less air it moves so the motors does less work, so the lower the current should be

    Either way it's about 6A which suggests its very restricted
    For comparison - with a 150 mm opening my old 3HP motor DC would draw about 9.6A

  9. #23
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    I'll give it another go tomorrow to double check.

    Might try it with the filters off to see if that makes much of a difference. I can't say how accurate that meter is either.

  10. #24
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    Nov 2016
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    USA, Indiana, West Lafayette
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    188

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    Quote Originally Posted by havabeer69 View Post
    I'll give it another go tomorrow to double check.
    If it's not too much trouble, would you also take a current reading with the inlet completely closed?

    Also, if your meter has the capability, power factor readings would also be helpful.

    Thanks
    Dave

  11. #25
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    So Sydney tools.have a home brand "bayer". They have a 3hp dust collector with 5 micron filter bags, I think their claimed "3900 m3/h (2200cfm)" is probably a little generous but the price is $469. Has anyone used this brand or have any concerns with it?

    I have a couple of the smaller Bayer vacuums on the boat, they've been absolutely flogged and have stood up well. I like the fact that I can take out the dust bag an use them for water and oil and just wash the plastic drum out. I reckon they are good value.
















  12. #26
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    Quote Originally Posted by riverbuilder View Post

    So Sydney tools.have a home brand "bayer". They have a 3hp dust collector with 5 micron filter bags, I think their claimed "3900 m3/h (2200cfm)" is probably a little generous but the price is $469. Has anyone used this brand or have any concerns with it?
    This is one of the cheapest/budget 3HP machines around. The claimed 2200 CFM is completely fanciful as it only has a 12" impeller and a motor that runs at 50Hz (2800 rpm) so the impeller is no better than the impeller inside a 2HP DC3. As shown by havabeer's current measurements the small impeller and restricted I/O does not appear to enable the 3HP utilise its full power. The significant advantage over a DC3 is that the bigger machine has 2 filter and 2 collection bags which for the low price is worth having as it provides less restriction than the single filter bag DC. It also looks to me like the filter bags are slightly larger than the DC3's single bag?

    To fully utilise the power of a 3HP motor requires using a 13" impeller and with some care a 14" impeller can be use.

    The other factor that determines flow is the size of the ducting used. A 3HP motor should be able to move ~1250 CFM through a 6" duct, but the DC3/DC7 type of 12" impellers (with no filters or bags attached) connected to a short 6" duct will at best draw about 1100CFM. Adding one (clean) filter bag, such as used on a DC3 drops the flow to ~865 CFM, so I would assume adding two (clean) filter bags will produce a flow to ~980CFM. Using 2 PFs will increase the flow to just over 1000 CFM.

    Given the price these DCs are still useful and worth pursuing for small workshops - just don't believe the claimed 2200 CFM.

  13. #27
    Join Date
    Nov 2007
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    melbourne australia
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    Quote Originally Posted by BobL View Post
    The claimed 2200 CFM is completely fanciful as it only has a 12" impeller and a motor that runs at 50Hz (2800 rpm) so the impeller is no better than the impeller inside a 2HP DC3.
    Are the impeller blades the same width (depth?). Same number of blades? Diameter is only one factor that determines an impeller's performance.

  14. #28
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    Nov 2007
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    Quote Originally Posted by havabeer69 View Post
    It then simmers down to around 5.8amps with the intake splitter off

    Intake splitter on and 2 ports covered was 6amp
    As already stated by Bob, they should be the other way around. They should also be substantially different.

  15. #29
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    Quote Originally Posted by jack620 View Post
    They should also be substantially different.
    Remember he's not blocking off the DC inlet completely so the difference depends how restricted the DC is to begin with. If the DC is already very restricted then restricting the DC further might not make that much of a difference.

  16. #30
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    Quote Originally Posted by BobL View Post
    Remember he's not blocking off the DC inlet completely so the difference depends how restricted the DC is to begin with. If the DC is already very restricted then restricting the DC further might not make that much of a difference.
    Come off it Bob. You spend half your time on here telling people they must open up there DE's 4" port to 6" to get good performance. Haveabeer's two measurements were with the inlet wide open (just under 6") and then with only one 4" port open. So roughly 6" versus 4". Are you now saying that won't make much difference? How restricted is a new DE with no inlet ducting and clean filters going to be?

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