Power-One solar Inverter driving me NUTS!!!

[truclacicr]

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

Where is the current transducer/transformer?

[mitsu2k]

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

Where is the current transducer/transformer?

The current transducer is that blue block you see in the center of the board with the black wire wrapped around it, and the two white wires going through it. That has been replaced. The transformers are in the photo attached. They are actually connected to the second board, that is deep within the housing. Please see attached photos above of that second board I am referring to.

There are also 4 other current transducers on the board that I cannot easily check.. I will circle them in the attached photo.

[mitsu2k]

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

I think it would be helpful to give everyone a sequence of events on this inverter. A couple years ago I got the E031 error. This is the error where the solder joints burn out on the relay contacts. I had repaired this error several times by re-flowing the solder joints, and making them really thick. I also added some 8 gauge wire strands across the contacts on the underside of the board. I am including a photo. Well, when I put the jumper wires across to reinforce the solder joints to make a better connection, I neglected to do one of them (circled). A couple months later - wouldn’t you have it, that is the one that burned out because all the others were properly reinforced. However, this time, when I noticed the inverter was not working, it also had the red GFI LED lit. This GFI LED was never lit on the previous times. I went ahead and checked the relay itself because it looked pretty burned up (see photos) and found that the relay was bad. So I replaced all four relays. But after replacing them, I still have the GFI light. . I will circle in the attached photo the contact that I had neglected to reinforce on the bottom side of the board for the relay, as well as the top side photo of the relay that is associated with those contacts that had burned out. I just seem to feel that the problem could have initiated or be related to this incident of the relay burning out. However, I cannot be sure. All I know is there had been some serious arcing going on at the contacts because they are burned really bad.

[CapLeaker]

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

Well, that makes more sense now. Seems like you had some carbon going on too. Unfortunately the pic of the bottom isn’t that clear (a bit out of focus) but it looks like there are bad solder joints?
One thing I learned is that shit can hide underneath a different component. I would go as far as going around with the megger and these a few things. Plus I would take some nearby components neighbouring the burnt relays and take them off and look underneath.

[mitsu2k]

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

Well, that makes more sense now. Seems like you had some carbon going on too. Unfortunately the pic of the bottom isn’t that clear (a bit out of focus) but it looks like there are bad solder joints?
One thing I learned is that shit can hide underneath a different component. I would go as far as going around with the megger and these a few things. Plus I would take some nearby components neighbouring the burnt relays and take them off and look underneath.

Yes, you are correct. I removed everything that looked cooked or experienced any kind of heat as well as neighboring components and checked all the traces underneath and verified for continuity. Everything looked fine. No other damaged traces aside from the large ones under the relays that were arcing due to the solder joints. I will try and take some better photos for you now. See attached.

[mitsu2k]

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

I will have the megger on Friday. Where should my test points be? I assume I would be fine testing on the DC input terminals. But would it be safe to test on the AC Grid input terminals? Are there any other test points you would suggest and is there a risk of the megger zapping something else? I have only used a megger once. If I am not mistaken, I would set the voltage, place the black probe to a ground and my red probe to the test point and start the test. I would be looking for a low reading to find a leak to ground. A high megaohm reading is good. Is this the correct way?

[stj]

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

relay joints shouldnt burn unless the relay pins are getting hot - are the relays burning inside?

[mitsu2k]

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

relay joints shouldnt burn unless the relay pins are getting hot - are the relays burning inside?

There are 4 relays that have exhibited this issue. This occurrence of the contacts burning out has happened to me about 4 times. Each in a different relay. Usually one relay at a time. It is a common issue with this inverter. If you Google “Aurora inverter E031 error” you will find several youtube videos on it. The first 3 times it happened the relays were still ok. The last time it happened one relay actually burned up and stopped functioning. I have a photo of it above in post #23

Under normal operation of this inverter, the relays can be heard cycling every couple seconds or so but obviously not now with the GFI error.

The GFI error may or may not be as some kind of side effect of the last relay burnout. I cannot be sure. However usually when the relays burn out, I get an E031 error but this last time, there was no E031 error. I only found the inverter with the GFI light lit and no error code. Very puzzling.

[CapLeaker]

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

I think this inverter is advertised for 3.6kw. This being said, I think it’s only good for 2.5kw tops.

Let’s see what happens when you get that Megger. Then go for the high voltage positive and negative DC to earth ground before and after the relays.

[mitsu2k]

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

Great idea! I did suspect that the relays not being clicked on would not give me accurate readings but your idea solves that problem.

[mitsu2k]

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

I think this inverter is advertised for 3.6kw. This being said, I think it's only good for 2.5kw tops.

Let's see what happens when you get that Megger. Then go for the high voltage positive and negative DC to earth ground before and after the relays.

What kind of readings should I be looking for with the megger? Meaning approximately how many megaOhms would you think should be normal? I do understand the higher the better.

[CapLeaker]

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

First off, a Megger test is done over time. So pressing the button for 5 seconds doesn't count unless its a short.
What is your string voltage of the solar panels? Since your inverter is going into ground fault with like minimum turn on voltage, I suspect you should read almost a short.
Usually 6 figures reading like 100 -1000 or better MOhms is good. once you get low readings like 1Meg that's no good. Some Meggers actually will tell you the voltage it can put out. So you want the max voltage rating it can put out for the selected voltage setting.
Example: Megger set at 250v, open leads: You get something like 261V 275MOhm. Great!
set at 250V and you get 1 MOhm.... well thats garbage.
Ideal would be the OL or the highest reading the megger can do.
What to expect? Hopefully that highest MOhm reading for the rated input voltage rating of the inverter. MOV's etc should test practically like OL. MOV not reading like OL, its garbage in my book.

[mitsu2k]

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

First off, a Megger test is done over time. So pressing the button for 5 seconds doesn't count unless its a short.
What is your string voltage of the solar panels? Since your inverter is going into ground fault with like minimum turn on voltage, I suspect you should read almost a short.
Usually 6 figures reading like 100 -1000 or better MOhms is good. once you get low readings like 1Meg that's no good. Some Meggers actually will tell you the voltage it can put out. So you want the max voltage rating it can put out for the selected voltage setting.
Example: Megger set at 250v, open leads: You get something like 261V 275MOhm. Great!
set at 250V and you get 1 MOhm.... well thats garbage.
Ideal would be the OL or the highest reading the megger can do.
What to expect? Hopefully that highest MOhm reading for the rated input voltage rating of the inverter. MOV's etc should test practically like OL. MOV not reading like OL, its garbage in my book.

Great info there. The string voltage is 250v. The inverter specs state that input voltage can be up to 600v dc. However I know I get the error at 100v so I will start at 100v and work my way up. The megger I will be using has I believe 125, 250, 500, 1000v settings. I think I will probably stay at 250 max because many of the caps are only rated for 305v. The biggest issue is going to be testing on either side of the relays. The issue being that there are many "GP" ground pole screws. 12 to be exact. This is where the board gets its ground. Only problem is, all those ground poles have no continuity to each other unless they are screwed to the bottom plate. I will attach photo. So I will have to come up with something creative to get around this.

[sam_sam_sam]

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

First off, a Megger test is done over time

This was an interesting explanation of how to use a megger on an inverter

The highest voltage megger I have used is the 500 volts version before which has the difference color LED lights tell you what megohm range you are in

[CapLeaker]

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

It's true, a Megger test for like 5 seconds is worth nothing unless it comes up with a basically short straight away. Gotta be at least one minute to test and if your MOhms value rises during that time, that's good and the end value at the one minute mark is used.

Yeah, go straight for the 250V rating on the Megger for this inverter high voltage rails. Don't even think on pussyfooting with a 100V or 50V.

I think you got too much voltage on the DC input from the panels to the inverter. You should have taken one or 2 panels off. On a cloudy day with sun peaking through a lot, you will be surprised how much peak power you get out of your panels. I've got 9.5kw worth on panels and I've seen over 11kw on these days.
10kw worth on panels on a 10kw inverter isn't a good idea. You'd be begging for trouble.

I've got a Fluke 1587, it tops out at 1000V. I don't use it often, but it surely comes in very handy for troubleshooting odd shit, like wiring, GFI, motors, generators, heat pumps, deep well pumps etc.

[CapLeaker]

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

Great info there. The string voltage is 250v. The inverter specs state that input voltage can be up to 600v dc. However I know I get the error at 100v so I will start at 100v and work my way up. The megger I will be using has I believe 125, 250, 500, 1000v settings. I think I will probably stay at 250 max because many of the caps are only rated for 305v. The biggest issue is going to be testing on either side of the relays. The issue being that there are many "GP" ground pole screws. 12 to be exact. This is where the board gets its ground. Only problem is, all those ground poles have no continuity to each other unless they are screwed to the bottom plate. I will attach photo. So I will have to come up with something creative to get around this.

Be careful what you test. You can't use the megger like that on low voltage things. So just stay at the high voltage DC power rails for now.
Put that inverter back together in the box and just test around on the high voltage DC rails (there are 2) with the cables disconnected between the boards. We don't know if the problem is on the first board with the bad relays, or the other board with the transformers and the caps.

[mitsu2k]

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

Be careful what you test. You can't use the megger like that on low voltage things. So just stay at the high voltage DC power rails for now.
Put that inverter back in the box and just test around on the high voltage DC rails (there are 2) with the cables disconnected between the boards. We don't know if the problem is on the first board with the bad relays, or the other board with the transformers and the caps.

Ok good idea isolating the boards. Just so I am clear, when you say "rails" can you please circle them on my photo? I am assuming you are referring to the DC inputs but I want to be sure.

[CapLeaker]

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

put the boards back into the chassis with all the wires disconnected in between them. Make sure you use all the screws on the boards!!! Then probe the DC Inputs labelled side (4 connectors) against earth ground and note things down. then go to the other end of the board where the wires with connectors plug in and test there. That would be the other side of the relays.

Go for the low hanging logical fruit first. Don't go too test crazy with the megger, because you can damage circuits that aren't meant to run 250v. Stick with testing the DC power inputs only.

[mitsu2k]

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

put the boards back into the chassis with all the wires disconnected in between them. Make sure you use all the screws on the boards!!! Then probe the DC Inputs labelled side (4 connectors) against earth ground and note things down. then go to the other end of the board where the wires with connectors plug in and test there. That would be the other side of the relays.

Go for the low hanging logical fruit first. Don't go too test crazy with the megger, because you can damage circuits that aren't meant to run 250v. Stick with testing the DC power inputs only.

You got it buddy. I will report back tomorrow. Thank you!!

[CapLeaker]

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

I went over these pictures again and maybe I found something or not. LOL
If you look at that spot I marked, it looks like a dark area (like a light burn mark) compared to the others.

Take your DMM in diode mode and check the 3 legs of all the IGBTs and diodes on this board. See if they are shorted or leaky.
How to IGBT? Here: https://www.incbtech.com/circuit-ben...s-ins045e.html