Power-One solar Inverter driving me NUTS!!!

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

Out of curiosity: The two 60V PSU's you are using to start the inverter, they aren't earth grounded on the negative? Just saying if you use one or two linear power supplies that have an earth pin on the power mains plug, the negative coming out of the PSU is coupled to earth ground.
Keep this in mind, that you may need a isolation transformer on these power supplies.

No they are not earth grounded on the negative. I actually an not using those anymore. I had borrowed them from a friend, so I had to return those. As it stands, I am just reconnecting it to the array to power it on.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

I have this happened to in the past working on a board that several relays had bad pin connections and it was a multi layer board the top layer was not getting any solder on the top layer but only the bottom layer because the trace in between was not there anymore and it drove me nuts to figure out why this board was not working properly

I would highly recommend removing all the relays and very closely look at solder traces between the top layer and the bottom layer and see if it looks like there should be one or not

I not suggesting that are but some time when the bottom traces are gone and there is a top trace the solder does not travel to the top trust me I have happened to me several times in the past

SAM, I have not yet removed the relays to look again, but previously I have looked several times. I am just a little hesitant to keep removing them and re-soldering them because the pads are getting pretty worn out. But the traces are pretty large and even if one of them does not make contact on the top, it still makes contact on the bottom to the same components. I did verify that by testing for continuity from the top against the bottom. However, these relays are on the A/C side of the unit and our problem seems to be on the DC side.

Also I need to mention that the burnouts were always on the high voltage contact sides of the relays. There are two pairs of relays. I will call them the top pair and bottom pair depending on how are looking at the board. On each pair, only one relay is getting the 12v to turn on. I tested this by connecting some jumper leads to the coil side of the relays and extending the wire outside of the board for testing. However this is likely normal because a GFI error dissconnects the grid side of the inverter.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

OK I just want to be thorough and follow your suggestions so I have removed the relays, unfortunately I did a little bit more damage in the process but that’s OK. Anyhow, the photos are attached.

I did check for continuity between all top holes and bottom holes after removing the relays and had continuity through on all 16 holes.

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

Oh boy, there is a lot of black PCP that would needed to be cut out, filled etc. it’s all exposed too ready to hold moisture… with a lot of DC power going through it, not good. I also seen a few little via’s that look a little sad.

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

Something else I noticed: while the instructions tell us to look at the DC side, it looks like all that GFI jazz is done on the AC side? Look at the AC output and follow it straight up. It goes to the CT transformer and the little relay that has something to do with it? Then this goes to these burnt relays. Maybe we are looked at it wrong, since the fault was supposed to be at the DC side. What if some protection device weither shorted or opened on the AC side to Earth ground? Is that maybe why you don’t get any error codes on the display, because we aren’t looking in the right spot?
At the AC output side there is a blue cap and some round cylindrical protection device, for shitts and giggles check those.
After all, if that is the case, the GFI can’t say there is something wrong on the DC because there is no fault there, yet the GFI wouldn’t work either making the light come on, because it lost connection to earth ground somewhere else.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

Something else I noticed: while the instructions tell us to look at the DC side, it looks like all that GFI jazz is done on the AC side? Look at the AC output and follow it straight up. It goes to the CT transformer and the little relay that has something to do with it? Then this goes to these burnt relays. Maybe we are looked at it wrong, since the fault was supposed to be at the DC side. What if some protection device weither shorted or opened on the AC side to Earth ground? Is that maybe why you don't get any error codes on the display, because we aren't looking in the right spot?
At the AC output side there is a blue cap and some round cylindrical protection device, for shitts and giggles check those.
After all, if that is the case, the GFI can't say there is something wrong on the DC because there is no fault there, yet the GFI wouldn't work either making the light come on, because it lost connection to earth ground somewhere else.

“Lost connection to earth ground somewhere”. That is plausible. I know that one of the times I pit it back together and tested, I got a “Riso Low” error which the manual did state is accompanied by the GFI led. Riso Low is the insulation resistance of the panels. I thought I had chapped something but then I realized that I had not put all the screws back in to save time. Once I went back and put put all the screws back in, the Riso Low error went away and it correctly measured Riso at 20mOhms. So you are correct. It could be losing ground somewhere. I will look again in the area you suggested. As far as moisture, I am not too concerned about that because the inverter is mounted indioors in my garage ao that helps.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

Here are some more photos with some of the blue caps removed.

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

check that "v4" device under MOV6.
Other than that I am starting run out of ideas for now.
All the current sensing is done via that CT next to the relays. How ever this is all on the AC side.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

check that "v4" device under MOV6.
Other than that I am starting run out of ideas for now.
All the current sensing is done via that CT next to the relays. How ever this is all on the AC side.

How would I check that? It tests open with a DMM.

By the way, I did replace the CT device. Expensive little sucker. Over $30 on AliExpress

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

This device I circled in the picture is open?
Verify that one (lower) end is earth ground. If it is earth ground and this device is open, well how is the MOV supposed to work?

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

I was previously told it should test open. See thread below.
https://www.badcaps.net/forum/showthread.php?t=124790

It may be that some voltage has to go through it but I fear blowing it if I test wrong.

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

If it is a gas discharge arrestor it should be open. If it’s a fuse, then not.

It goes from line to earth ground? If a gas discharge, it’s for lightning protection.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

If it is a gas discharge arrestor it should be open. If it’s a fuse, then not.

It goes from line to earth ground? If a gas discharge, it’s for lightning protection.

Based on the little information, I have gathered it looks like a gas discharge. I don’t think it’s a fuse, but I can take some better pictures of the numbering on it.

It is denoted with a “V” like the other 4 bulb looking things so I assume it is a gas discharge. If it were a fuse, I would think it would be denoted with a “F“

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

I think I found something. This dialed circled is testing open in both directions. The remaining are testing fine. Now the question is how to identify it.

This would also make sense in that maybe there isn't a real ground fault but the detection circuit is wacky. I've included a better picture of the markings.

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

I think I found something. This dialed circled is testing open in both directions. The remaining are testing fine. Now the question is how to identify it.

This would also make sense in that maybe there isn’t a real ground fault but the detection circuit is wacky. I’ve included a better picture of the markings.

I think you fund something!!!
try cleaning it off with 99% IPA so we can read it better. looks like a diode?

[petehall347]

Re: Power-One solar Inverter driving me NUTS!!!

closest i can find are zener . BZT52C22 . but testing open suggests tvs . never seen diodes fail open . suppose it could happen though

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

closest i can find are zener . BZT52C22 . but testing open suggests tvs . never seen diodes fail open . suppose it could happen though

I think it is an 18 V Zener. All the others in that row test fine. I had another 18 V Zener but not SMD so I sorted it in and I'm putting it back together to test. The markings are. WN -3D it looks like but i think the relevent markings are the WN. It is marked exactly the same as the rest so I am assuming it is a Zener just like the rest. I too have never seen one fail open.

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

Follow the tracks and see what is connected to that zener. Never mind… saw the pic.

[mitsu2k]

Re: Power-One solar Inverter driving me NUTS!!!

It is 100% definitely open

[CapLeaker]

Re: Power-One solar Inverter driving me NUTS!!!

I’ve seen open zeners before. So while it is on the rare side, it’s possible.