Generator transfer switch

[Jlubas]

So I am totally confused while working through an issue on my generator. I have a 1995 Carver 355 Aft Cabin. It has a Kohler 6.5kw s/n 347222 if that helps.

The boat is fairly new to me, lost an engine last year on my maiden voyage so it never left the dock. This year started using it and working through this generator problem. What is interesting is I don't have a transfer switch on the panel. This has me super perplexed. I thought maybe there is an automatic transfer somewhere I cant see?

Here is what I am experiencing, if I am on shore power, turn the generator on and switch the breaker pull on the generator to the on position the generator will take over, I can turn the shore power off and the generator will work okay.

If however, I am not on shore power turn the generator on and then flip the breaker pull to the on position it makes a loud buzzing sound on the panel and shuts down.

If I am on or off shore power and I keep the pull in the on position and try to start the generator it will not stay running.

Coming off the generator there are the three normal wires that go into what appears to be a capacitor of some sort first.

Capacitor.jpg

My assumption is this is intended to clean the power from the generator before it goes to the panel. I traced the "out" line from the capacitor and it appears to go straight up to the panel.

I reviewed the original schematics and it appears there was an intention for a transfer switch in the panel. There is clearly a spot for it but there is nothing there. I opened up the panel and everything looks extremely neat and organized, like it would have been from the factory. It doesn't appear that anything was changed. All connectors match and there is black starboard where the extra switch opening is.

My assumption is there is some kind of automatic transfer switch somewhere that I cant find. I am also summing that is the cause of the issue. No clue where to go from here. Any suggestions would be GREATLY appreciated!! Thank you.

[tomschauer]

The transfer relays SHOULD be behind your main AC panel. That's were they are on my 1998 355. The relays fail closed to shore power, the coils are energized by the 120vac output of the generator causing them to transfer the load automatically.

[Jlubas]

Thanks Tom, so how can I get to the relay? Pull out the refrigerator? Sorry I am a bit of newby with generator stuff.

[tomschauer]

Hopefully someone with your vintage will chime in, but for mine you remove the front panel screws (after turning off the power) and pull the whole panel out. You may have an access behind your refer.

[jcoll]

The capacitors are a common problem with the symptom you describe. They should be available locally to you at an electrical supply shop. If not then there are some online sources. I don't remember who I bought mine from but I can dig it up if you'd like.

[waybomb]

Just remember to short out the capacitor. They can produce a nice shock

[Jlubas]

JColl, waybomb,

Thank you both very much. So does the boat have an automatic transfer switch or is that what the capacitors and whatever that other thing are doing? It just seems shocking to to me I have no switch. Really appreciate the feedback.

[km1125]

You could replace the automatic relays with a manual switch. Start the generator, flip the switch, and you're on generator power. Flip back to shore power when you want.

The capacitors are part of the automatic switch. The capacitors are to help "lock" the relays so that they don't bounce back and forth between the generator and shore power when there are fluctuations in voltage (such as when a big load like A/C comes on). This is called chatter and will also burn up the points on the relays.

[Jlubas]

Source of the post You could replace the automatic relays with a manual switch. Start the generator, flip the switch, and you're on generator power. Flip back to shore power when you want.

The capacitors are part of the automatic switch. The capacitors are to help "lock" the relays so that they don't bounce back and forth between the generator and shore power when there are fluctuations in voltage (such as when a big load like A/C comes on). This is called chatter and will also burn up the points on the relays.

Km1125 so do you think that I could be having a problem with the automatic relays? Where are the automatic relays located? I think it is fine to have the automatic relay but I want to make sure that I can get things working appropriately if I need to switch over to a manual switch that is fine, but I can’t seem to locate the automatic relay? Is that the circular piece in the picture that I have above?

[km1125]

I think your problem MIGHT be a relay, but it is more likely just one of those capacitors.

You either have two double-pole relays, or four single pole relays. These relays ARE the transfer switch (an automatic one) I don't know exactly where they are on your boat, but every time this comes up someone says they are in a box behind the electrical panel. You should be able to follow the wires from that box with the capacitors and see where those wires go.

Be careful working around the AC circuits. Make sure everything is "dead" before you go messing with connections and make sure the capacitors are discharged. As someone pointed out before, the "buzzing" symptom is usually caused by failing capacitors... you might want to get the part numbers off the ones you have and get a couple on order.. they are not very expensive. If you replace the capacitors (and they were the problem), you may never need to find the relays.