Design of steel frame mount and vibration isolation

[xyzer]

In my opinion we all have different balance values to deal with. The only value close to being constant among us 6/1er's is the power pulse. The link below is of a balanced 6/1 at 65% balance not bolted to anything. Before it was balanced it would eat you for lunch! It surely would have needed 2 yards minimum to appear to be balanced. I'm sure it would still send vibes through the ground. The secret is in the 65% value. We have 11#'s of reciprocating mass to deal with and only 6#'s rotating. With these things you don't know what you got till you start it or have it balanced. All the rest is speculation in my opinion.   


http://video.google.com/videoplay?docid=-9194771268947755783

Dave

[trakorb]

In my opinion we all have different balance values to deal with. The only value close to being constant among us 6/1er's is the power pulse. The link below is of a balanced 6/1 at 65% balance not bolted to anything. Before it was balanced it would eat you for lunch! It surely would have needed 2 yards minimum to appear to be balanced. I'm sure it would still send vibes through the ground. The secret is in the 65% value. We have 11#'s of reciprocating mass to deal with and only 6#'s rotating. With these things you don't know what you got till you start it or have it balanced. All the rest is speculation in my opinion.   


http://video.google.com/videoplay?docid=-9194771268947755783

Dave

Dave, looks like you got this one running pretty smooth.   I've read tons of posts on balance topic.  Out of curiosity, what did you end up doing for balance on each wheel in terms of weight & distribution.  Thx, Craig

[xyzer]

Craig,
The one running is Vidhata with 1+#'s added strategically to each flywheel in the vicinity of the cast in counterbalance It was way off! My new powersoulutions needed very little weight added. The Poweresolutions was in ounces. I haven't run it yet but it was dynamically balanced the same as the Vidhata's 65%. The Vidhata has a lead weight bolted to the inside of the rims.  I balanced the Vidhata by trial and error lots of starts and stops till I couldn't get it any better. I then took the flywheels off and we put them on the balance machine using the powersoulutions crank to find out what % balance I had arrived at. It was the 65% mentioned. Then we proceded with the same % on the powersolution. It should be smooth also. A trick I learned from the balance guy was modeling clay. It will stick inside of the wheel rim and can be moved, lightened or added to easily. Once you know how much and where you can add the weight. Still a bunch of work but so is a teardown and spend money to have it balanced.
Dave

[trakorb]

Thanks Dave,
The 6/1's I'm setting up will have Stover wheels, so I'm looking at options on the way of balancing them out.  There is quite a mix of balancing req'd and some have req'd adding weight to the off-side of the spoked counter weight wheel.

How expensive was it to get this done on a machine if you don't mind my asking?

Craig

[xyzer]

$250.00...included polishing the rod journal. It is a pain to do! Those flywheels are so damn heavy! I will re think it on my next one.
Dave

[trakorb]

Whoa.  I think I'll make up a fixture and do some spin balancing here and call it good.
Thx again, Craig

[Guy_Incognito]

As mentioned in the "engine mount 4.0" thread, I was thinking about a long-ish frame that is simply fixed at the generator end with a pivot/hinge, with the engine at the other end resiliently mounted.

This would allow:

- The engine to jiggle vertically in the y axis as much as it liked, dependant on spring rate.
- The X and Z axis forces are constrained by the pivot. You could just grease up a few bolts if you wanted. Maybe a fairly stiff donut mount would be the go there.
- Things to be a bit cheaper if you're using expensive airmounts, as you only need one or two under the engine, as opposed to a plethora of mounts spread all over the place.
- All the misc pipework and wiring to come out across the pivot for minimal flexing and movement.
- You can level your engine frame to match your suspension by adjusting the pivot height.

Going from that, I was basically thinking for me to build a large box frame, then mount a slightly smaller rectangular frame inside that with the engine/genny on. The engine frame attaches to one side of the box frame - possibly with donut mounts for a little bit of isolation there. Height of the pivot point could be adjusted with boltholes in the outer frame or clamped somehow for testing purposes. The larger box frame then also provides a convenient mount for water and fuel tanks, guarding, etc.

With an adjustable pivot height, one can test a lot of suspension types easily. Want to try a few tyres? Chuck 'em under and adjust the height. Got some springs from an old car? Give them a go. Want to suspend your engine frame from above with bungee cord? Well, with a box frame around the engine frame you can do it, but make it pretty strong 

Length of the frame would need to be fairly long so that forces on the pivot end are reasonable and thus little vibration is transferred.  Too short and the engine would try and tug the pivot point up and down with it as it moves.

Thoughts?

[mobile_bob]

GI:

might be an interesting concept and experiment,, if built right you could test a variety of springs, shocks, etc.

bob g

[lip5er4]

How about using hockey pucks for engine vibration? Drill a hole through the center it. Mount it under the engine with large washers or put a series of them under your frame. Anybody? Anybody?

[hotater]

lip5er4---

I've used hocky pucks for years in polishing blocks...maybe it's the kerosene, but they harden and begin to crumble after a while.  I sure wouldn't use them as motor mounts.

Machinery mounts, built as you say, are available in many different capacities, but very expensive.

[Technonut]

I purchased 4 anti-vibration mounts for my Isuzu genset here: http://www.avproductsinc.com/mobile-marine/fail-safe-mounts.html They work very well, and were only around $23.00 each for my application....

(Edited 22/Feb/2016 to fix link)

[peterako]

Oke let me hook in on this with my experience.
i have a LOvson 6/1 little giant DI with only the first power stroke excepting the engine is running balanced my first run wash on the street ( asfalt) and during the first 5 min run it moved les then 4mm.
I orded from Lovson also the mounting frame ( the cost wash lower the the steel price in Greece  )
it is a full P cannel frame and so stif that i can lift it on one corner with the engine and cooling and gen on it with out measerable twist.
Its paint job wash a nightmare and i repainted in gloss black and it looks like it is dript in tar and fits perfect with the Green.
My next run wash on this frame incl. generator. fixed to heavy duty pallets ( every pallet +/- 80 KG).
My first run the compleet setup wash on it is 5HZ freq. starting for a slow but steady run.
My second run i just rubber fibrion fixing from a truck between the engine and the frame.
And yes i have a nice running set again, but then i checked the belt and the pulsing on it wash greating anice black dust below the generator ( the rubber dust on the gloss paint wash clear enough for me).

And on the final installation  yes i made a big isolated block of concrete 2M*0.7M*0.7M = around 1000kg.
The steel frame on that using 12 chemical ankers whitout fibration rubbers.
the set is running perfect i am also using a tractor muffler and the ony sound is mechincal from the valves.

My other hobby is checking for earthquaks and i can measure low freq. ground movments. special because i know the 5HZ and 10HZ. i see on 100 meter distance a 5 hz piek put low ( me goning to the sensor is a last twice the piek) and nothing on the 10HZ   do i have a pefect balanced flywheel maybe.

for me the concrete blok is a perfect solotion .
oke i know if i stated looking for more material maybe i found a good balance to filter out. put the cost for this blok wash around 100 EURO incl the labor from two pakistani works mixing the concrete for me.

i just to work on a very old sailing ship and the generator is a o yes a lister fixed to the steel frame , my beth 4 meter away and the nice sound wash perfect to go to sleep and the lister filled up the batterys and heated nicely the rooms. This wash my first love.
This lister after 60 years nearly every day work wash until 18 years ago compleet original. the klipper 36 m by 6m proved more than enough mass for the lister. ( by the way a new owner replaced ( cuted in pieces ) by a yanmar gen set.
after the first month the first problems came yes the internal fibration cracked the cooling system. and the new owner  orderd a deutz generator and the story ......................................................................

For me if you want life time of your genset you need a good fixing concrete or wood , steel put heavy realy heavy and your lister will be your best friend