Inverter load Balancing

[YukonDon]

I Live off grid in The Yukon I use 2 Xantrex matched SW5548's in 240V configuration using a Xantrex SWI Serial cable.  I find that I occasionally hit the 5500w max on any one leg and it dumps my whole grid.

I have been looking for a Xantrex SWI/PAR a parallel load balancing kit that has been discontinued a number of years ago. I have also looked at the Outback PSX240 balancer however it will only support 6000w not the 11K I have available.

Does anyone know where I can find either a Xantrex SWI/PAR  or a Load balancing Transformer that will support around 11000 Watts.

YukonDon

[dang]

Wow - interesting problem. I have a SW5500-plus... and a TX6A and am curious!

Has this always happened or is it just being seen now with no other changes? Does the problem persist if the master inverter is swapped to the other of the pair? Has anything changed on the battery-generator leads to unbalance them? Have you heard of that happening to others using stacked SW5500's? Did Xantrex Support have anything to say?  Have you pitched the problem-questions at the Outback Forums?

Just a note, when stating transformer or other inductive power its deigned Volt-Amperes (VA) for the label ratings, so that's a better search term on your hunt... Trace/Xantres had a larger auto-transformer the TX6K that was rated for 6000VA, versus the 2900VA allowable on the T240.

I'm not sure the autotransformer design being inherently non-isolated is what you need - more like a 1:1 ratio isolation transformer capable of 12,000VA constant duty which is a manly hunk of iron! I know toroidal transformers can be stacked in parallel to increase the through-put amperage, not sure about autotransformers.

Long ago on the Web, and now lost to time, was a project where someone wound their own high-power toroid transformer using nearly a roll of narrow steel pallet banding wound up opposite from what it was on the roll it came on - several thousand continuous strand tiny doughnuts using teflon anf kapton  tape as inter-layer insulation on a form about two feet in diameter... It'd be unwind the coil onto a long board to act as the bobbin of a winding loom to pass through the eye of the toroidial circle and cinch it down tightly as its being wound. Not something to attempt lightly - but something I always wanted to try someday..

There are many listed on ebay - http://www.ebay.com/sch/?_nkw=Toroidal%20Transformer , today I'm seeing a 5kVA 220:220 direct from India for a mere $300 with free shipping. 

[YukonDon]

Thanks for the comment.

I did talk to Outback but didn't get much help. Their PSX240 max's at 6000W. Whats strange is that they must have some way of load balancing because you can stack 4 or 6 of their inverters. you would think they could handle more that 6KW. I am not familiar with all their product line.

My system has been up and running for 10 years now, the issue has always been there, however as with all things we use more and more power so it is becoming more of an issue. In a perfect world I could just buy the SWI/PAR and eliminate the 240VA configuration I have now and hook up the SWI/PAR and have access to 11KW at 110VA. But alas I can't find a SWI/PAR. It was rated for 11KW.

I don't have any 240VA appliances so getting rid of the SWI cable is no problem.

 

[ChrisOlson]

I don't have any 240VA appliances so getting rid of the SWI cable is no problem.

We have two SW Plus 4024's with split phase output and a T240 to step the split phase down to 120 V for 120 volt loads.  The majority of our heavy loads are 240 volt, however, and the 4.5 kW output of the T240 carries our 120 volt loads with no problem.

I think, in the absence of the SWI/PAR kit, I would look at your loads and switch motors that are drawing a lot of power over to 240 volt, and any other appliances or tools that can be switched to split phase power.  11 kW at 120 volts is over 90 amps and that's ridiculous for 120 volt loads.

I run my Lincoln 225 arc welder off the inverters with no problem at all.  We have 240 volt induction range, 240 water heating, well pump, and a clothes dryer.  The inverters will run them all except for the clothes dryer.  With other normal loads on (usually around 1,500 watts) the master will start the generator for peak load if my wife fires up the clothes dryer.
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Chris