Transformers, balancing

[mike90045]

So, I'm still looking for a 240V 10KVA balancing transformer.  (auto-transformer)  I know Trace used to have one, and Outback has a small one.  But who wants an E I core transformer, with a cooling fan (smells like losses to me) when there is technology for toroid transformers.  I've found some tiny ones, but nothing as large or efficient as I want.   Has Midnight looked into offering these ??  Anyone have any sources ?

[tallgirl]

Mike,

The insertion loss for an X240 is supposedly on the order of 20 watts.  My recollection of your system is that's a few minutes a day worth of PV production.  Better quality fans have power consumptions that are likewise in the range of "noise".

[mike90045]

Well, I don't know what the fan will consume, where it's on / off points are set.  Since no mention is made of the outback transformer efficiency, I'll have to guess it's average, about 94% idle, and 90% loaded.  Summertime, I've got plenty of light and power, but winter, it gets much, much tighter. 

It's the odd, unbalanced loads, like the vacuum cleaner and then switching on the garbage disposal, that may load one side of the inverter, and glitch it.  In a conventional house, I don't worry much, it all generally averages out, but off grid, it's much more important. (to not have to go out to the shop to reset the inverter at night or in the rain.)

Still looking ...

[boB]

Those transformers can have losses (dissipate) of around 150 to 300 Watts  depending on how the are used and how much you are putting through them.

They will have lower losses when used for balancing than for isolation.

boB