From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Using generated power on large sound systems?
Organization: NASA Langley Research Center and Reptile Farm
Lines: 34
NNTP-Posting-Host: grissom.larc.nasa.gov

In article <1rk733$ekv@slack.sim.es.com> pashdown@slack.sim.es.com (Pete Ashdown) writes:
>
>I've bothered the rental shops and audio shops about the problem, but most of
>them have precious little experience in dealing with generated power.  My
>suspicion is that I don't really need anything larger than 2KW and this could
>all be resolved with a transformer of some sort.

Nope.  Your problem is either being caused by excessive voltage drop in the
long cable from the generator, or just plain not having enough power.  I
would suspect that those amps are going to draw a lot of current on short
peaks.

You can try using larger (and shorter) cables to the generator, or try
strapping the amps for 240V service and running 240V mains cables out,
which will minimize the line drop.  If these don't work, though, you're
going to need a bigger generator.

I assume that you're using well-maintained generators, and have watched the
voltage output on the generator properly.  If you don't have 120V coming out
of the unloaded generator you'll never get 120V at the other end.

>Can anyone offer any advice?  I want to do a lot of outdoor events this
>summer, and it would be nice if this power problem could be resolved easily.
>I've been looking into buying a power-pack so I could tap into junction boxes
>directly, but have no idea where to start.  One that would resolve my
>generator problems as well would be of high value to me.

I recommend you talk with an electrician who has experience in this sort of
work, and not with the pro-audio people.  Also, I recommend that you don't
try to tap into junction boxes at all, but hire a licensed electrician if
you don't really know what you are doing.  I've had to clean up after two
people who nearly killed themselves playing in hot 200A boxes, and it wasn't
much fun.
--scott
