Ethical dilemma, Quad SW Systems [RE-wrenches]

Fri Aug 17 09:40:36 PDT 2001

William and Ezra,

While it may be Xantrex's official position that they do not offer a "quad"
SW configuration, I know of at least one "quad" SW system in operation and
another scheduled to go in. Ezra, what's the rest of the story?

Pat Kiernan

Eco Electric, Inc.
PO Box 550
Carbondale, CO 81623
tel/fax (970) 963-3132
e-mail: ecoelec at rof.net
----- Original Message -----
From: Ezra Auerbach, Trace Engineering <ezra at lasqueti.net>
To: <RE-wrenches at topica.com>
Sent: Friday, August 17, 2001 9:33 AM
Subject: Re: Ethical dilemma [RE-wrenches]

> William,
>
> I think you are doing the right thing, safety in schools is paramount.
Bill
> Hoffer is correct in his posting, Xantrex does not offer a "quad" SW
> configuration.  My personal suggestion would be to get the loads separated
> into two panels and feed them from SW series pairs.  On my rock the PTA
> would cough up the dough if the school was too strapped to do it...It's
not
> really that much work.
> Ezra
> ----- Original Message -----
> From: "William Miller" <wrmiller at slonet.org>
> To: <RE-wrenches at topica.com>
> Sent: Monday, August 13, 2001 9:37 PM
> Subject: Ethical dilemma [RE-wrenches]
>
>
> > Fiends:
> >
> > Here's a dilemma and how I dealt with it.  I am still wondering if there
> is
> > a better solution.  Your thoughts are appreciated:
> >
> > I was called by the operations director for an off-grid elementary
school
> > to replace fans on an SW inverter.  While on site, I took some time to
> > learn how the system was built.  There are 4 SW inverters with outputs
> > summed through 2 levels of transformers.   They run their generator
during
> > the school day and ran on batteries and inverters during the afternoon
and
> > evening for extra curricular, janitoring and etc.  The system runs great
> > while fed by the generator, but when the generator shuts down, inverters
1
> > and 2 are not synced to inverters 3 and 4.  You can measure the voltage
> > from phase to phase and over a half hour or so it goes from 240 to 0 and
> > then back up.  The output of the equipment room is two hots and a shared
> > neutral.  When the inverters are out of phase, the neutral is properly
> > shared.  When the inverters drift in phase, the neutral current will
> > increase, possibly until the current is double the rated current.  It is
> my
> > understanding that power is distributed throughout the school in this
> > manner.  At any point where a neutral is shared--on a feeder or
multi-wire
> > branch circuit--this condition is possible.
> >
> > I wrote a report describing this problem as clearly as I could.  I
> followed
> > up with phone calls to the operations director.  Last conversation I was
> > told that there was no money to correct this problem and that all they
> > could do is, "conduct extra fire drills."
> >
> > I wrote to the school and told them I could not work for them until this
> > issue is addressed.  I do not want to be even associated with a system
in
> a
> > public school that has an obvious design defect.  I feel pretty
> comfortable
> > about this decision, but I am curious what others might have done.
> >
> > William
> >
> > __________________________________________________________________
> > William Miller
> > SLO Communications: Communications and Power Systems Consulting
> > PO Box 50, Santa Margarita, CA 93453
> > Voice :805-438-5600 Fax: 805-438-4607 VMail: 805-546-4875
> > email: wrmiller at slonet.org
> > License No. C-10-773985
> > _____________________________________________________________
> > Compatibility:
> > Word processor: WP7
> > Spreadsheet: Quatro Pro 7
> > CAD: Microstation 95, DXF, Visio 4.1T
> > _____________________________________________________________
> > "I stand by all the misstatements that I've made." Dan Quayle
> > __________________________________________________________________
> >
> > - - - -
> > To send a message: RE-wrenches at topica.com
> >
> > Archive of previous messages: http://www.topica.com/lists/RE-wrenches/
> >
> > List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm
> >
> > Check out participant bios: www.mrsharkey.com/wrenches/index.html
> >
> > Hosted by Home Power magazine
> >
> > Moderator: michael.welch at homepower.com
> >
> >
> >
> >
>
> - - - -
> To send a message: RE-wrenches at topica.com
>
> Archive of previous messages: http://www.topica.com/lists/RE-wrenches/
>
> List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm
>
> Check out participant bios: www.mrsharkey.com/wrenches/index.html
>
> Hosted by Home Power magazine
>
> Moderator: michael.welch at homepower.com
>
>
>
>
>

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9
Or send an email To: RE-wrenches-unsubscribe at topica.com
This email was sent to: michael.welch at homepower.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================