[AT] reducing noise on portable generator

[Dean VP]

Ivan:

I won't be at Portland but I understand your objective. If I remember my
Physics theory correctly, putting a smaller pulley on the generator and
engine will allow you to run the engine at a lower speed but it will require
more power to keep the generator outputting 2400 watts. A large pulley at
the generator requires less engine power than a small pulley. 

Now if my above statement is correct, the engine will be running at a lower
RPM but it will have to work harder and you won't necessarily get a
reduction in noise. I would think you would want to know what the power
curve of the engine looks like at various RPM's. More power required = more
fuel used = more noise. 

I also suspect the generator has to be driven at some minimum RPM to be able
to achieve decent 115V regulation. I suspect with a smaller pulley it would
be more sensitive to sudden load changes as the engine would take longer to
recover. 

>From my perspective, I would work on trying to quiet the engine down through
a better muffler set up first. I own a Honda generator here for back-up
house power and paid a bit extra for it because the Honda engine was much
quieter than other generators I looked at. I've never taken the time to
determine if there was more to that difference other than just a better
muffler arrangement. Maybe the Honda engine design is part of the solution
too. 

Where I'm sitting right now, in my office, is directly above where the
generator is located in the garage. When it is running at heavy load, 5000
watts or more I can just hear a hum in the background up here. I'm about 10
feet from it vertically through an insulated floor/ceiling. Maybe the
insulated floor is the real reason.

Up close and personal it is still quite noisy, in my opinion, but a lot less
than others I have heard. Sometimes a large baffle such as a temporary three
sided wall with a top made of absorbing material such as foam rubber or
Styrofoam can offer a significant improvement. Any sound absorbing material
would help I would think. 

One thing I have noticed is that as I get older it isn't quite as noisy.
Probably has something to do with my deteriorating hearing! :-) Just park
next to really elderly campers. They won't hear it. Hope this generates (no
pun intended) some solutions some how. 

Dean A. Van Peursem
Snohomish, WA 98290

I'm a walking storeroom of facts..... I've just lost the key to the
storeroom door 


www.deerelegacy.com

http://members.cox.net/classicweb/email.htm



-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com] On Behalf Of ivan
Sent: Tuesday, May 17, 2005 8:07 AM
To: Antique tractor email discussion group
Cc: sel at lists.stationary-engine.com
Subject: [AT] reducing noise on portable generator 

 Ok , this is for use at Portland so its on topic.  But I dont want to p***
everyone off listening to a gen howling away .. So I put together a belt
driven generator so we can run the ac in the camper by day  . Its chuggin
along at 2400 rpm , with 115 under a 2400 watt load . Much better than one
screaming at 3600 rpm .  But how to quiet it down a little more  ?
 I would like to put a smaller pulley on the gen itself so that I can lower
the speed a little more ,target is1800 rpm and I have one of the lo tone
mufflers from briggs  .So its a little quieter than a jet turbine .
Suggestions ? Ivan


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