DC ISOLATOR (faulty)

[powervan]

Anyone had a DC isolator arc out on them? first time today switched on array and smoke poored out plus the conacts arching out big time!!!!all rated correctly replaced it and all was fine but (bit of a wake up call supplier said he supplied thousands and never had a prob so JUST ASKING out of intrest??????????????

 

[The Solar King]

What make of DC switch? Many are little more than modifed AC units. Andy at Sibert who posts on here can tell you a whole lot more.

 

[VMan]

i have had one fail after a functional test, it was on my frost MCS install and i though i had buggered up the inverter!!

 

[moggy1968]

We've had a couple of faulty ones. nothing this spectacular, just not allowing any current through.

 

[coomers]

Did you use one isolator for two strings? I did this once many moons ago on one of my first installs, took out factory links on a 600v dc isolator and used it as a four pole, basically derated isolator swiched on and whoosh smoke pouring out. lesson learnt 1 isolator 1 string ,unless of course you use factory made 4 pole.

 

[powervan]

well no links left in and one string but (out of intrest ) isnt each contact in switch rated at 16amp? so shouldnt matter? or am i being simple .

 

[SibertSolar]

What make/model is it? What are your Voc and Isc values for the string?

 

[coomers]

you have to remember dc has no 0v like ac so these extra poles and the quick switching action help with the dc "arc" when making or breaking.

 

[powervan]

got u! spread the load !each side of the switch by leaving links in!! never thought of that bet a few have done the same could be nasty if done when suns out this being 1 string of 16 240w panels its gonna jump!! glad i never did that then but put new switch on and it was fine(well u learn something everyday)
cheers lads!!

 

[SibertSolar]

Hmmm, are you saying that you didn't take any links out and then wire your string instead to one pair of the poles? If you didn't then that's more of a worry as to why your unit failed.

I'm guessing your Voc is about 750VDC and your Isc is about 8A?

I wonder if the problem could have more to do with the fundamental nature of how the contacts made when you turned the switch (did you switch it rapidly??) Let us know what make/model too if you can, PM me if you prefer

 

[moggy1968]

I don't really understand why someone would take the links out. This is how the manufacturer designed it, why would someone change that?

 

[powervan]

Ref isolator salzer dc switch !! checked it out and just one contact in + side burnt out links were all secure just must of been a duff one!! nice switch plenty of room made in india! anyway system PUMPING it OUT today so all happy!!