3 HP motor and impellor vibrations

[Barry Burgess]

I want to flip my motor and impellor from my dust extractor and fix it to the roof rafters

I don't want to drill holes in the rafters and I don't want the vibrations to resound through the garage. How do I suspend the motor from the rafters???
Thanks for your help.
Barry

 

[Chris Knight]

Barry,
I see no reason why cables or chains shouldn't work. Starting torque may cause a bit of movement but after that it should be fine.

 

[Jake]

Washing machine springs?

I think I might have some somewhere in my cellar, from a machine that bust. If I can find them, you can have them if you want them. It might wobble around like crazy, though.

 

[ike]

Use hooks and 4 rubber exhaust system hangers. Angle them outwards to minimise movement.

Ike

 

[Bean]

Barry using exhaust rubbers is all well and good but they may not last long or perform very well. Rubber performs best in shear compression or pure compression but not in tension.

You can buy specially designed mounts to hang motors from the wall or roof. Try a distributor such as Robush.

 

[ike]

Bean wrote:

Barry using exhaust rubbers is all well and good but they may not last long or perform very well.

Seeing as they are designed to hang a load from I can't see why they won't work. If they can last ten years holding a bloody hot pipe under a car in all weathers, why won't they work for this application then?

Ike

 

[Anonymous]

Bean wrote:

Barry using exhaust rubbers is all well and good but they may not last long or perform very well.

Seeing as they are designed to hang a load from I can't see why they won't work. If they can last ten years holding a bloody hot pipe under a car in all weathers, why won't they work for this application then?

Ike

I think the extractor is very much heavier and vibrates considerably more and am with Bean on this. Rubber mounts are well known to work best in compression, not extension.

I would not hang my dust extractor from rubber but would mount a plate perpendicular to the wall and mount the extractor on there (with anti-vibration mounts in compression)l

 

[Inspector]

I did a search for anti-vibration mounts and there are tons of them out there, and i'll put up a couple of links to get you started although I think searching from your end will give you closer options. You can also search for Lord Mounts. They are a staple in the aircraft industry. But since you are a good scrounger you can probably adapt some engine mounts from a small car. If you were here I'd just tell you to use some Hockey Pucks. happy hunting.

http://www.vibrasystems.com/?src=overture

http://www.vibrationmounts.com/

http://www.maplin.co.uk/Module.aspx?Mod ... ed+Gearbox

http://www.avproductsinc.com/

http://www.ultralightnews.ca/ultralight ... mounts.htm

http://www.rpmmech.com/lord.htm

 

[ike]

If there is a point to my argument for using rubber donuts, then it's that it is a cheap, simple solution.

For less than a tenner surely it is worth a try?. If there is the worry that the rubber rings will fail, then include a short length of arrester chain across each hanger.

Just my two-penneth. Maybe it's a crap idea but i'd personally give it a go.

cheers,

Ike

 

[BrianD]

Hi all,

may I be a PITA :roll: and ask if you know where I can get anti-vibration foot mountings for my table here in the UK.

I have searched the net in the UK and it seems the companies are only industrial and behave BU2BU only.

Can you point me in the right direction?

Appreciated,

(before everyone complains - yes I know it is not the topic but is is related somewhat; OK obscurely)

 

[Barry Burgess]

Thanks for all the info. My roof rafters are 100X50mm and are at 360mm centres. What I was looking to use two wooden stretchers above the rafter and the motor suspended below the rafters. Had pucks being readly available like in Canada I would have used them between the rafter and the stretchers. Just having spoken to Bean I will have to do a re think.

 

[dedee]

Barry,
pucks are available & only £1 each!

http://www.iceisus.co.uk/store/shop/sho ... and%20tape

Andy

 

[engineer one]

barry i would have suggested a frame around the rafters probably 2x2's would suffice. the mountings could be at the top, and the motor mounted
underneath, this giving the compression that makes these mounts
work more effectively.

you could join the frame together using LOOOONG coach bolts that
go through the mountings, and the motor mounting.

star washers at each level between a number of nuts at each level
would make the whole thing pretty secure.

as for ike's suggestion i think it is really a weight issue mate.

basically exhausts on cars are actually not very heavy, certainly i think
lighter than the motor would be, also they are not used in a situation
where torque on a continuous basis makes a difference to the
usage.

go for it mate.

paul :wink:

 

[9fingers]

Try RSWWW.com and search on vibration.

I have feeling that increasing the mass is going to help reduce vibration. Perhaps in the experiments you could try stacking some bricks on the motor mount and see if it helps.
Obviously, doing everything to balance the rotating mass will help. A mixture of drilling holes in the impeller disc and maybe fitting nuts and bolts in the holes will subtract and add local weight. Make sure the bolts are really tight.

good luck

Bob

 

[Bean]

I have feeling that increasing the mass is going to help reduce vibration. Perhaps in the experiments you could try stacking some bricks on the motor mount and see if it helps.
Obviously, doing everything to balance the rotating mass will help. A mixture of drilling holes in the impeller disc and maybe fitting nuts and bolts in the holes will subtract and add local weight. Make sure the bolts are really tight.

Your right mass does help but it will also increase the need for a bigger stronger frame. orientating the mounts so that they work in shear compression will also take care of the torque!

Instead of pucks you could also use tennis balls for the weight and cost they are worth a try.

Exhaust rubbers are not designed to absorb the frequency that this piece of rotating machinery will produce, they are simply designed to hang the free end of a tube, which is bolted at the fixed end to an engine. Some cars do not use the rubber rings anymore, they use fulley bonded mounts and they fail frequently as rubber does not like being in tension. I have seen the mounts fail on the assembly line before the car has been run.

I have hung a garage door motor on hoover belts, but yes you do need a check chain for safety.

 

[Barry Burgess]

Bean I used tennis ball in the final design see the other thread
I have PM you
Barry

 

[JFC]

Im suprised no one has said sky hooks :lol:
You may want to take into account that if you suck up a small offcut of timber it may break one of the fan blades and make the whole thing wobble like mad ! I did this to my extractor and it was scary enough with it stood on the floor .

 

[Barry Burgess]

You may want to take into account that if you suck up a small offcut of timber it may break one of the fan blades and make the whole thing wobble like mad ! I did this to my extractor and it was scary enough with it stood on the floor .

JFC I have a cyclone - the chips and dust get caught there and very little fine dust gets to the impellor.
Barry

 

[Scrit]

May I be a PITA :roll: and ask if you know where I can get anti-vibration foot mountings for my table here in the UK.

Brian

Try Machine Mart and ask for anti-vibration mountings for compressors. Hope that's what you are looking for

Scrit

 

[JFC]

Just ignore me :lol: