Generator vibration isolation

[jetart]

Hello,

The previous owner of my bus put in a VERY sweet running Perkins 404D-22G - 15KW generator.  However, it's isolated using small round rubber donuts (~ 2" dia and 1" thick) that appear to be solid rubber.  The engine transmits some annoying (to me) vibrations into the bus.  Does anyone have a source for a better mouse trap?  Air bag, liquid filled, .  Looking for any ideas......

Thank you!

[Jeremy]

A friend of mine in the NVH industry sorted me out with the correct mounts for my generator from the gazillion different types available. He asked how heavy the generator was and about the number of mounts it needed, and the spacing between them - then did some calculations (no idea what exactly) to figure out exactly what would best suit my application.

A good industrial supply outlet might be able to go through the same exercise with you, or at least make some well-educated guesses

Jeremy

PS. I used to work for Perkins!

[bobofthenorth]

What Jeremy said but good luck finding anyone who knows anything about doing the calculation.  Until I found some genuine Onan rubbers I used 4 firm foam rubber balls, about 4 inches in diameter.  Drilled a hole through the middle and squished them down under the gennie feet.  They actually worked well enough that I didn't really notice much difference when I put in the Onan parts but I don't suppose they would have survived for very long.

[bansil]

Is there a chance that the rubber is too hard and the noise your hearing is actually the harmonics from the floor vibrating?
Maybe stick a sheet of adhesive backed rubber/asphalt under genny between the mounts to dampen the floor?

[Sam 4106]

You could check with your generator's manufacturer to see if they offer an alternative to the rubber donuts. Dick Wright (Wrico International) 541-744-4333 could possibly supply air bags or suggest a solution. He builds the Wrico brand generators, is a bus owner, and is very helpful.

Good luck, Sam

[Zeroclearance]

Take a peak at some of the Prevost conversions.   You can see the Goodyear bellows being used.   

[sledhead]

I have used orange foam hockey pucks (cheap and soft foam )           dave

[belfert]

I've read about folks using small pneumatic tires to isolate vibration on generators.  Definitely more of a home built solution.

[Lin]

So not everyone used an old pair of flip flops as I did?

[wg4t50]

I got my 4 mounts from WW Granger Catalog, it will work better if you know the approx. weight on each foot, if unknown go with 200 lb each, might be a little stiff but better than setting on the bottom and depending on engine and generator, one end is always heavier, so a little fore thought can be rewarding.
Dave M

[Seville]

I've been trying to figure out how I could lessen the vibration from the generator in my bus as well.
An idea I got from a friend who owns a recording studio is to use sand bags. The type photographers use to hold down their gear.
Sand apparently is a great way to control the low end rumble that a generator produces. This method is used some recording studios, so in theory could work for our application.

I plan on taking on this project when the weather breaks a little. I will report back with my results.

[chessie4905]

Some used to use a lead covered panel material. I'd check out this site

http://www.fatmat.com/

I've used this stuff in vehicles and it does a great job

[jetart]

THANK YOU everyone for all the great ideas.  I'll put my thinking cap on and do some research.  I'll let you'll know what I end up doing.

[luvrbus]

Use the SML series from www.vibrasystems.com they work or they have other models to suit your need

[gus]

I don't know what my Honda 250 lb gas gen uses but it is amazing!