Author Topic: Generator vibration isolation  (Read 13006 times)

Offline jetart

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Generator vibration isolation
« on: February 20, 2013, 10:45:28 AM »
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!
'82 Prevost LeMirage, 8V71NA,6 speed Spicer

Offline Jeremy

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Re: Generator vibration isolation
« Reply #1 on: February 20, 2013, 10:57:24 AM »
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!
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Offline bobofthenorth

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Re: Generator vibration isolation
« Reply #2 on: February 20, 2013, 11:10:07 AM »
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.
R.J.(Bob) Evans
Used to be 1981 Prevost 8-92, 10 spd
Currently busless (and not looking)
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Contrary to popular belief, wise men do not learn from their own mistakes
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Offline bansil

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Re: Generator vibration isolation
« Reply #3 on: February 20, 2013, 12:03:25 PM »
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?
Doug
Mnt City TN
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Offline Sam 4106

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Re: Generator vibration isolation
« Reply #4 on: February 20, 2013, 12:08:16 PM »
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
1976 MCI-8TA with 8V92 DDEC II and Allison HT740

Offline Zeroclearance

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Re: Generator vibration isolation
« Reply #5 on: February 20, 2013, 12:14:14 PM »
Take a peak at some of the Prevost conversions.   You can see the Goodyear bellows being used.   

Offline sledhead

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Re: Generator vibration isolation
« Reply #6 on: February 20, 2013, 02:36:39 PM »
I have used orange foam hockey pucks (cheap and soft foam )           dave
dave , karen
1990 mci 102c  6v92 ta ht740  kit,living room slide .... sold
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Offline belfert

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Re: Generator vibration isolation
« Reply #7 on: February 20, 2013, 03:25:39 PM »
I've read about folks using small pneumatic tires to isolate vibration on generators.  Definitely more of a home built solution.
Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN

Offline Lin

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Re: Generator vibration isolation
« Reply #8 on: February 20, 2013, 05:55:57 PM »
So not everyone used an old pair of flip flops as I did?
You don't have to believe everything you think.

Offline wg4t50

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Re: Generator vibration isolation
« Reply #9 on: February 20, 2013, 06:07:03 PM »
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
MCI7 20+ Yrs
Foretravel w/ISM500
WG4T CW for ever.
Central Virginia

Offline Seville

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Re: Generator vibration isolation
« Reply #10 on: February 20, 2013, 10:13:22 PM »
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.
New York City
1984 MC9 6v92T

Offline chessie4905

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Re: Generator vibration isolation
« Reply #11 on: February 21, 2013, 04:04:02 AM »
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
GMC h8h 649#028 (4905)
Pennsylvania-central

Offline jetart

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Re: Generator vibration isolation
« Reply #12 on: February 21, 2013, 07:10:49 AM »
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.
'82 Prevost LeMirage, 8V71NA,6 speed Spicer

Offline luvrbus

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Re: Generator vibration isolation
« Reply #13 on: February 21, 2013, 08:00:38 AM »
Use the SML series from www.vibrasystems.com they work or they have other models to suit your need
Life is short drink the good wine first

Offline gus

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Re: Generator vibration isolation
« Reply #14 on: February 21, 2013, 04:19:42 PM »
I don't know what my Honda 250 lb gas gen uses but it is amazing!
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