Hi All.

I want some advice. I have a system with 2x 5kw Axpert inverters paralled. System has been going good for about 1yr no issues. Now it cuts out on error 72 which is current sharing issue. Problem is it is not consistent. And can trip now continuously. Other times it can work a week no problems other times just a trip and restart.

What can be wrong? Some say parallel card, others say load sharing cables, others say synchronisation issues.

Cable work is fine. And what makes this hard that it is inconsistent but yet often that it is an fault

13 hours ago, Byron said:

Now it cuts out on error 72 which is current sharing issue. Problem is it is not consistent.

I've had suspicions that some paralleling cards can't take the extreme summer temperatures. Is it possible to squirt one of the paralleling cards with a "can of cold" when this happens, reset if necessary, and see if that delays the problem coming back? Repeat with the other one.

I forget the proper name for the "can of cold"; something that's electrically insulating and evaporates quickly, cooling the area.

1 hour ago, Coulomb said:

I forget the proper name for the "can of cold"; something that's electrically insulating and evaporates quickly, cooling the area.

https://www.communica.co.za/products/cramolin-freeze

Coulomb thank you very much. Much appreciated. I wont be at site to spray it. But when i can is that site is near Phalaborwa in Limpopo which is very hot... So temp can have an influence although i also doubt as lately its happened around 5am. When it gets to the stage where it constantly happens in other words not even an reset works. Cause then my client needs to by pass thr system where the inverters have an opertunity to cool down. So I think its is part of the problem but not the source of the problem

1 hour ago, Byron said:

So I think its is part of the problem but not the source of the problem

Perhaps uninverting the fans would help. With the factory installation of fans, the minimum fan speed approximately balances out (negates) the natural cooling due to convection. So at low power (e.g. overnight), the inverter can actually get quite hot, compared to during the day when the fans run faster.

Making the fans blow upwards should roughly double the cooling due to convection, and this might help prevent the error 72s.

If it's costly visiting that site, it might be worth it to just buy a new pair of paralleling kits, and replace both paralleling boards. The original boards might be OK as spares for less hot sites.

I would also turn the fans around while you're there; it's about 10 minutes work per inverter when you've done it before.

Coulomb thank you very much. Much appreciated. I wont be at site to spray it. But when i can is that site is near Phalaborwa in Limpopo which is very hot... So temp can have an influence although i also doubt as lately its happened around 5am. When it gets to the stage where it constantly happens in other words not even an reset works. Cause then my client needs to by pass thr system where the inverters have an opertunity to cool down. So I think its is part of the problem but not the source of the problem

I was on site yesterday. Redid the wiring. Swopped the inverters interms of who is boss and also checked the connections of the cards to inverters. In other words all possible hardware issues except replacing the cards. 

 

And the heat issue with the fans thats an really good idea cause it does get.hot there... Very hot so i hope its sorted now but lets see

Hi Byron, did you ever get error 72 again?