Auto Transfer Switch

[bud37]

Do you have the make and model number of that switch handy ?

[km1125]

Each one of those little circles in your "automatic transfer switch" box is a double-pole-double-throw relay. One for inlet "A" and one for inlet "B". The generator output feeds both relays (on the 'energized' contacts) and also energizes both relays. With no power from the generator, the power should pass directly from each inlet to the main breakers on the main panel. One of the relays is either stuck in the "energized" mode or the contacts are bad on the 'de-energized' mode.

[ngriffin]

Allright, was finally able to get access to the automatic transfer switch. By the naked eye doesn't look like anything special. Looks like the generator (wires coming in from the bottom) connects to the bottom terminals, the shore power white/black, one plug goes to one switch, and the other to the other switch and then the house breakers/outlets/ac come out the top as the black and white leads. All Grounds are connected together and zipped down. Looking to find a comparable replacement ATS.

[bud37]

That looks factory to me......good pic......it seems to resemble the one in my boat.....from the pic, it looks like one of the contacts is a bit more discoloured than the others with perhaps some corrosion, may just be the way the light is.....hard to tell really and I know very little about these things, second from the top.

[km1125]

I had to go back and re-read what the symptoms were.

Yes, the top contacts look like they are discolored. You could likely take a fine emery board and run it through there to clean them up. The contacts at the right of the pic are the ones that would come from the shore power connection. The ones on the left go to your panel and the ones in the center come from the generator. I'm guessing the top relay is your #1 main and the bottom is your #2 main. Obviously, if you're working inside that box make double SURE there is no power entering either from the shore power or from the generator, and no way to automatically start the generator.

If you look close on the relays, you might find a part number. You might also be able to get it by emailing Carver.

[ngriffin]

That picture is actually side ways, so the bottom is actually the left side, does someone mind indicating where i need to clean with an emery board?

[bud37]

Heh there....not sure what KM was referring to but the only thing I noticed was the contact which is now the second one from the right at the bottom as shown in this pic.......like I said before, I know very little about these particular ones, but my guess would be that all the contacts would have to be clean for it to work correctly.....also I will also mention all power off including any inverters if you have them....good luck man and be careful..

[Midnightsun]

I custom built my own box and believe it or not it used 2 heavy duty contactors just like in the picture. Heck looks pretty much like the box I built. I did this as I added a secondary shore power inlet on the port side as on the starboard side only was sometimes a pita. This was on my previous boat.

Point is you would be better off just changing the relay/contactor as opposed to sanding the contacts . They are only about $35. See here
https://www.amazon.com/NTE-Electronics-R04-11A30-120-Multicontact-Arrangement/dp/B00DWIKF2A

Just a note. Sanding down the contacts will only supply a better contact, I doubt it will fix a non working unit. Most likely the solenoid in there is bad which is what actually closes the contacts.

[ngriffin]

Well i did some testing. So, in the past I've read these things default/fail to shore power but clearly thats not the case. I can see when it's running on shore power that one of the solenoids activates and changes position, the other however does not. I have to assume that it is bad, and I've ordered a replacement. thank you all

[Midnightsun]

Source of the post Well i did some testing. So, in the past I've read these things default/fail to shore power but clearly thats not the case. I can see when it's running on shore power that one of the solenoids activates and changes position, the other however does not. I have to assume that it is bad, and I've ordered a replacement. thank you all

You can easily rewire so it is default to shore power which is how it should have been designed IMHO. Energizing the coil should only happen when the generator is run.