Low voltage out of Genset

[Alan Johnson]

Bob,



Thanks for your help. I should have mentioned that the voltage readings I
posted are at the circuit breaker box using a Fluke multimeter. I took the
box cover off and measured the volts coming into the main circuit breakers.




_____

From: WanderlodgeForum@yahoogroups.com
[mailto:WanderlodgeForum@yahoogroups.com] On Behalf Of one_dusty_hoot
Sent: Wednesday, August 23, 2006 10:57 AM
To: WanderlodgeForum@yahoogroups.com
Subject: [WanderlodgeForum] Re: Low voltage out of Genset



Alan, the generator is holding the rpm very well,
+/- a half cycle, can't get much better than that.

Increasing the speed from 1800 rpm may increase
your voltage slightly but at the same time all
AC components like to run on 60 cps, not 65-70,
whatever it would take, and you would have excess
heating of the AC motors as well.

Your coach meters indicate they are correct by
measuring the incoming shore power at 120 VAC.

It is now necessary to measure the voltage by
a meter other than the coach meters. You need
to know if the output voltage at the genset is
the same as what you have read and noted.

If it is the same, then it's generator output V.
It it is higher, then it's a voltage drop between
the genset and coach meters.

If it is the same, meaning the generator output
is low, I don't know the cause. I read that this
generator did not have brushes and if so they
cannot be the problem.

If the voltage is higher then you will have to
trace the lines from the generator to the
trasfer switch, the common point where you did
get 120 VAC shore power.

Sorry, this is as far as I can help you.

Bob Janes, '87FC35 Greenville, sc

--- In WanderlodgeForum@
yahoogroups.com, "Alan"
wrote:
>
> Ok, here are my findings so far.
>
> 1. Engine RPMs - right at 1800 (I bought a vibration tach, as
> suggested.)
> 2. Frequency stays right between 59.5 and 60.5 whether under heavy
> load or not.
>
> Leg 1 Leg 2
> ------ ------
> No (very little) load 108v 108v
> Front a/c only 104.5 110
> Both a/c's on 104 101.5
> Rear a/c only 100 91 (a/c compressor is having
> trouble running)
>
> When on shore power I've got right at 120v. On the generator, I'm
> obviously low on voltage all the time, but do these different
> readings tell you guys anything? Do I just need to up the rpms, or
> will that mess up my frequency??
>
> Thanks!
> Alan Johnson
> 87FC35
>
>
>
>
>
>
> --- In WanderlodgeForum@
yahoogroups.com, "Alan"
> wrote:
> >
> > My 87FC35 has a 8.0 kW genset. I am getting low voltage out of
it
> > (around 95 volts). On my last onan genset (77 GMC - carbed gas),
> > this was a common problem and was simply corrected by increasing
> > RPMs. (If this is the fix, how do I adjust idle speed? This
fuel
> > injection isn't as intuitive for me as I've been a carburetor
guy.)
> >
> > I found an installation manual for the genset and it says to
> adjust
> > some "taps" on a transformer regulator. It also says "output
> > frequency is determined by engine speed and normally does not
> > require adjustment." I'm not exactly sure what it means
> by "output
> > frequency". Is that voltage??
> >
> > Is this problem more complicated than adjusting the RPMs? Maybe
I
> > don't have one of the Onan manuals..?? I have a parts manual and
> an
> > installation manual.
> >
> > I have searched the forums and did not find a post that seemed to
> > address my situation. Let me know if I missed it.
> >
> > Thanks in advance,
> > Alan Johnson
> > 87FC35
> >
>





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