X-240 Balancing Transformer
jcheil
Solar Expert Posts: 722 ✭✭✭
OK, so I have a 2 inverter setup (Outback Stacking Configuration) with the X-240 transformer set up as a balancing transformer for 120/240 split phase. Right now, the slave inverter sleeps most of the time (when the total load is 1000w or less) and the 240v is provided by the transformer.
However, I noticed that if I run a rather large 120v load on one leg (such as my compressor which draws 15amps and surges to at least 20 or my small mig welder), at some point the X-240 double-pole 20-amp output breaker will trip. It will do this even when the generator is feeding the inverter.
So I spoke to outback earlier and they said the breaker was tripping due to an imbalance greater than 20amps between the loads on the 2 legs (which I think makes sense). They offered 2 suggestions:
They think it is possible that the slave inverter is not waking up fast enough to handle the additional load, thus overloading the X240 due to the imbalance and tripping the breaker. They suggested turning off the power ranking on the slave inverter -- basically let it run all the time and never go to sleep.
The other option, that they have implemented in other systems and most commonly in larger systems, is to add additional X-240 transformers in parallel with the first and increasing the output breaker to a larger breaker. In this case I would have to add the external enclosed PSX-240 because there is no room for another X-240 inside the FW500 enclosure. Meaning I would then have a 45a DP breaker instead of the 20 (because the external transformer has a fan and is rated at 25a). Kind of an expensive $500 addition, but...
I have disabled the power ranking as a test and will try running the compressor again tomorrow, but then I started thinking...doesn't that defeat the purpose of having the X240 to begin with? If I was going to leave the other inverter on all the time, what benefit would I even have using the balancing transformer?
Your thoughts, comments, real-life experiences are welcomed.
Thanks,
Jay
However, I noticed that if I run a rather large 120v load on one leg (such as my compressor which draws 15amps and surges to at least 20 or my small mig welder), at some point the X-240 double-pole 20-amp output breaker will trip. It will do this even when the generator is feeding the inverter.
So I spoke to outback earlier and they said the breaker was tripping due to an imbalance greater than 20amps between the loads on the 2 legs (which I think makes sense). They offered 2 suggestions:
They think it is possible that the slave inverter is not waking up fast enough to handle the additional load, thus overloading the X240 due to the imbalance and tripping the breaker. They suggested turning off the power ranking on the slave inverter -- basically let it run all the time and never go to sleep.
The other option, that they have implemented in other systems and most commonly in larger systems, is to add additional X-240 transformers in parallel with the first and increasing the output breaker to a larger breaker. In this case I would have to add the external enclosed PSX-240 because there is no room for another X-240 inside the FW500 enclosure. Meaning I would then have a 45a DP breaker instead of the 20 (because the external transformer has a fan and is rated at 25a). Kind of an expensive $500 addition, but...
I have disabled the power ranking as a test and will try running the compressor again tomorrow, but then I started thinking...doesn't that defeat the purpose of having the X240 to begin with? If I was going to leave the other inverter on all the time, what benefit would I even have using the balancing transformer?
Your thoughts, comments, real-life experiences are welcomed.
Thanks,
Jay
Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
Comments
Would it be possible to ventilate that enclosure and upgrade the circuit breaker?
Not sure I would want to hack up the FW enclosure and try to rig up a fan.
Besides that would only gain me the 5amp increase and not sure if that would make a difference.
This won't help you but your problem is really caused by running a large long duration 120v load that really should be 240v.
htps://offgridsolar1.com/
E-mail [email protected]
That's a good point, I will have to look at the motor on the compressor and see if it can be rewired for 240v. I know many motors can be, but with my luck, this one prolly can't
Why not run the 2 inverters in parallel? One could be in sleep mode most of the time except when there is a large load. The transformer could handle only the 220 volt stuff. That what I was thinking of doing when I add another VFX-3648. Has been a very good inverter, just wish I could run more things when the sun is shining and the batteries are charged.
Unless I am misunderstanding you, that is how I have it hooked up now.
Outback stacking 120/240 split phase with the balancing transformer.
The slave inverter is sleeping most of the time and the 240 being provided by the transformer.
If you look at my online graphs prior to 2 days ago you can see that the slave inverter rarely wakes up.
But due to the imbalance of the load on the legs, I am having this problem.
Is it more then one load on the inbalanced side causing the imbalance. If you know of two loads on might be able to be moved to the other leg in you breaker box.
gww
http://www.manualslib.com/manual/498558/Outback-Power-Systems-Fx-2012t.html?page=19#manual
Check this out for a parallel operation. Look carefully at the AC out of both inverters. They are on different breakers, but go to the SAME bus bar for AC. I think you may be going about it a different way. There are at least 2 ways to use 2 inverters and have 220 volts with a transformer. I have a PSX-240 and a mate 3, but I only have the one inverter. Will also need a hub of some description too.
Hooked up this way, the only way a breaker blows on the transformer is when you are pulling more than 20 amps out of either leg of the 220 volt side only. Hooked up per the link it would not be an issue and you can turn the transformer off if you are not using 220 volts. My heat pump is on the transformer and when off the two of them draw about 30 watts. It really adds up if you are not using 220 volts all of the time. I often turn off the transformer to save power when I don't need 220 volts.
All my other loads are pretty close to perfectly balanced on the main panel. I made sure of that when I wired it.
It's only when this one "occasional" large load is started that causes the (obvious) imbalance.
Yes, I am running 2 FX inverters in an Outback Stacked configuration using the X240 as a balancing transformer. Your method using one inverter makes sense if you need to produce 240 and can only do so using the X240.
This is how I have it configured:
Attachment not found.Attachment not found.
What did you figure out about making that one large load into a 240 volt load. Are you talking a air compressor or an icebox compressor.
Gww
Air compressor, and I have not yet gone out to the shop to look at the motor yet. been busy with real-life work
If the motor can be rewired to 240, then your percentage voltage drop and required wire size will both go down. Certainly worth looking into.