[RE-wrenches] magnum question

[jay]

HI William,

I appreciate your time and input as to your thinking about this project.

However this system already exists and has been in operation for some time.  
Client has a offgrid farm with 45kva generator.  

The situation is that the main house also already runs off this generator, but the generator doesn’t run 24/7/365.  The other times of the year they run a honda 6500 at 120/240vac to power the house. The existing infrastructure of the farm is already set up for 120/208 3 phase and it wouldn’t be necessary or wanted to change all that for 7kw of inverters.

That all said, I’ll probably run the inverters at 120/240 setup, as the back up generator is 120/240.  And when they use the 3 phase generator its on 24 hrs a day.  Yes it will only use 1 inverter to battery charge, but given 24 hr charge time, it’ll keep up the batteries no problem.

Thanks to all,

Jay









> On Apr 2, 2020, at 11:31 AM, William Miller <william at millersolar.com> wrote:
> 
> Jay:
>  
> This idea sounds wrong on many levels.  Generators are designed to be loaded evenly, with some allowance for normal deviations.  Having separate loads that can vary independently is asking for regulation problems.
>  
> You did not state if the generator was wound Wye or Delta.  This makes a difference. 
>  
> Delta wound generators that provide 120/240 have one winding center-tapped.  That winding can provide only 1/3 of the rating of the generator (there is some research that says the de-rate is greater).   If this is the case, your two inverters can each access only 1/6 of the generator capability.  Sure you might be able to draw more than 1/6, for a while...
>  
> Have you checked to see if the generator can be field re-tapped to provide 120 only?  Then you could provide a generator-fed distribution and put all of your 120 loads on it, providing the full generator capability.
>  
> It has come to my attention recently that two Outback FXR (or FX, I am not sure) inverters can be stacked on two legs of a three-phase input power source.  I had thought this was not possible.  I know it works because I accidently did this.  I believe the supply was Wye configured.  It was with a mobile set up built by someone else.  The inverters should have been the Mobile version, and maybe this is what made this possible.  You just can't use an X240 on this setup.  Consider this option if you must unbalance the generator.  Try to balance the loads and charging between the inverters and avoid power-save settings (you can't power-save without an X240 anyway).
>  
> I have had many customers ask me to do something that my intuition told me was a bad idea.  When I was younger I might comply, and learn to regret it.  Good luck and stay strong.
>  
> William Miller
>  
> -----Original Message-----
> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org <mailto:re-wrenches-bounces at lists.re-wrenches.org>] On Behalf Of jay
> Sent: Wednesday, April 1, 2020 4:39 PM
> To: RE-wrenches
> Subject: [RE-wrenches] magnum question
>  
> Hi All,
>  
> My question is can a single  Magnum remote run 2 inverters each as master for 120v?
>  
>  
> I’ve got a client with a 3 phase generator, and I need two phases, but I don’t need 240v.
>  
>  
> 1. I can’t change the generator
> 2. Two phases because I can’t load one phase that heavily.
>  
> I can do 2 Outback FXR’s each as a master,  but I’d need to have 2 Mate3S’s.
>  
> But I don’t know if magnum has that possiblity?
>  
> Thanks
>  
> jay
>  
> Peltz Power
>  
>  
>  
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