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From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Wiring transfer switches
Date: Mon, 20 Aug 2007 17:48:10 -0400
Message-ID: <0h2kc3pvv1k0sl8668okgegtn1q7tneops@4ax.com>

On Sun, 19 Aug 2007 19:34:09 -0700, njphoto1 <njphoto1@gmail.com> wrote:

>I have a Honda eb6500x that I want to use to power certain circuits in
>my house during power outages.  The generator has two seperate power
>producing circuits, Main circuit I is 18.8a and Main circuit II is
>22.9.  I understand the need for transfer switch to isolate the
>generator's power from the power companies lines.  I can not see
>anyway to wire the generator into the house circuts that does not
>require two transfer switches and still allow me to use the full
>capacity of the generator?  Am I missing something?

It's not unusual to see one winding/output rated at slightly more than the other.
Mostly specsmanship.  If you measure between the hots of the two outlets you'll see
240 volts.  That is, the generator is (or should be) connected to produce normal
240/120 volt output just like utility power.

Physically, the generator has two (sometimes more) windings.  They can be connected
phase-alike to provide double each winding's amp rating or they can be connected
phase-opposite to provide 120/240 volt output.  Normally when a generator has two
different output ratings, the windings are connected phase-opposite.

You can easily verify this by checking that hot-hot voltage.  If it's 240 then the
generator is wired phase-opposite.  If the voltage is zero then it's wired
phase-alike.

If it happens to be phase-alike then you should be able to rewire it phase-opposite.
Examine the generator's schematic to find the color/label of the two windings.
Reverse the connection of one winding.  Pretty much all there is to it.  Inspect the
schematic to make sure the regulator still sees the proper voltage and make sure the
legs are separate all the way to the outlet.

I recommend installing a 14-L50 twist-lock outlet on the generator if it doesn't
already have one. (If it does then it is surely already wired phase-opposite). That's
the most reliable connector available for a portable connection.

If you can find an on-line copy of the manual (lots of luck with Honda) or would care
to scan your schematic then I'll be happy to take a look and confirm all of this.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Wiring transfer switches
Date: Tue, 21 Aug 2007 05:16:53 -0400
Message-ID: <rralc358s0ouhgidt4ku23uvecco4lfvrt@4ax.com>

On Mon, 20 Aug 2007 21:12:06 -0700, njphoto1 <njphoto1@gmail.com> wrote:


>There are two 240 4 prong connectors on the generator and they make a
>big issue about balancing the load.  If I connect to the house using
>the 30a and I am reading everything correctly then I am only using one
>of the two power generating circuits.
>Here is a link to the owners manual.  It is a pdf that I could not
>grab just one page from.
>http://www.hondapowerequipment.com/Gen_Own_Web/pages/eb6500x.htm  I
>own the EB6500X.
>
>Thank you for taking the time to answer.
>Greg.

You're all set as the generator sits.  Just make up a cord from your transfer switch
to the L14-20 outlet.  It's already wired for 120/240.

About balancing the load.  Loading one side of a 2 pole (3600 RPM) generator but not
the other can set up torsional vibrations in the rotor that have, in a few reported
incidents, resulted in broken shafts.  This is a rather extreme condition not often
encountered.  The onset of this vibration is a growling noise from the generator.  If
you ever hear an un-natural sound coming from the generator (not the engine) then hit
the breaker and find out what is wrong.  I've tried and have never been able to
induce one of my generators to vibrate but the reports are in the literature so it's
a good idea to keep that in the back of your mind.

As long as both legs are loaded reasonably the same, no problem.  That should be the
case with a properly designed residential electrical system where the electrician
selected branch breaker locations to balance the legs.

If you have one, it's not a bad idea to amp-clamp each hot leg and compare their
currents.  If one is much higher than the other then perhaps a breaker needs to be
moved from one leg to the other (moved one location in the breaker panel).  This is
sometimes also necessary when the generator is operating near full load to avoid
overloading one leg.

John


 
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