Unknown Broken Part - Help!

[turkish6]

Hey everyone,
We went to the boat today and found that my batteries were drained because my charger was not kicking in. looking into the problem I believe I found out what the problem is but I can't seem to find the part anywhere plus a few people I spoke with at the dock and west marine said they have never seen that part being used in a boat. The picture of the part is below and basically it has a maganic underneath and when replays on and off. If I push on the relay my changer and 120v plugs turn on and when I let go they all turn off and only batteries are working. I have six wires coming into the box. 2 grounds 2 positives and 2 negatives. One set is directly from shore power and the other set seems to go to my circuit panel. 2 weeks ago there was noise coming from the box and I gave it a tap and it went away. What is this part for, do I need it? and most important how do i fix my problem....

[scotte]

Looks like a relay to me, but I don't know what it's doing on your boat...

[Microship]

Yes, it is a 110-volt AC DPDT (double pole, double throw) relay. I agree with Scotte - what is it doing on your boat? I'd be curious to know where the wires to the coil come from... can you trace them? The big contacts are switching the load.

I can't quite tell from the fuzzy photo, but there is a slight chance that it is wired as a latching relay, disconnecting if there is a glitch. But that doesn't really make much sense, unless the charger is fragile. Find the black coil (the electromagnet) and see what is controlling it; that will be your clue.

I have some of those if the relay is bad, but a better solution is to figure out why such a contraption is in the loop between shore power and your charging system.

Steve

[turkish6]

everyone says the same thing. "I have never seen that on a boat"


how to i bypass it. I have no idea

[Microship]

Well, that's why I ask what is driving the coil. If it turns out that it's nothing you care about, then you can just connect the wiper wires to those on the normally open contacts... that would be exactly like holding it down as you describe. But I wouldn't advise you to do that without first knowing why someone put it there.

[turkish6]

I am sorry I did not see your first post before I posted my response.

The left side of the relay is the part that goes up and down. the wires from that terminal seem lead away from the engine bay and is headed right for my electrial panel that has all my swithches for electronics, water pump, bilge pump etc. the right side of the relay is stationary and wires from that are headed straight aft to my shore power inlet.

as a side not.. I believe the previous owner had an inverter that later disconnected. there were also 3 wires that were connected to this box and was a dead end on the other end.

[Microship]

You haven't mentioned coil wires leaving the box, just what sounds like the shore power in and the output (after switching) to your electrical panel. If coil wires don't leave the box, then it is likely that it has been set up to disconnect and leave the system off in response to a brief power interruption. That can prevent brownouts or intermittents from driving your whole system on and off, but there has to be some kind of reset for that to make any sense. The fact that it was buzzing (not at all unusual for old open-frame relays) certainly proves that it was being energized, but by what?

If you would, locate the black wrapped coil that is the actual electromagnet. Where do those two wires go? Directly to the switching contacts you describe above, or elsewhere?

Cheers,
Steve

[turkish6]

no coil wires are exiting. the wires are hooked up like i said. below is a picture of it before i took all the wires off. it's impossible to tell what it is but maybe a trained eye will know...


btw how much are you selling these boxers for?

[Microship]

Hi...

Gak, it's really hard to figure that out from the pic. If nothing else leaves the box, it must be set up as I have speculated (anyone else out there, please feel free to chime in if I'm missing something!). I don't want to tell you to bypass it and then discover that there was some very good reason why it was there.

Besides, the standard AC color code doesn't fit with the presence of the red, brown, and yellow... are those the three that dead-ended?

As to my back-stock, I do have some old relays; it would not be much... you can PM me if you want. I'd rather see this contraption go away completely, though; old boats (like mine) often have mysterious old kluge circuits that made sense 20 years ago but are now irrelevant. It is probably safe to experiment with black-to-black, green-to-green, and white-to-white; that should essentially bypass the whole thing with the equivalent of it being energized.

Anyone have other thoughts on this?

Steve (currently aboard, working on power stuff)

[Talbot]

I am wondering if it is an automatic switch over to mains when the shore power is connected.

[GordMay]

This might be an AC Source Transfer Switch (contactor), either manual or automatic.
It might not be a Double Throw Contactor, but a Normally Open Contactor; wherein the energised coil closes one input (Shore Power Source) to the panel output, and a de-energised coil defaults the contacts to the other input (Ship Inverter/Generator Source) to output.

If Manual:
There will be a source selector switch (Shore Power or Ship/Inverter)wired in series with the coil.
If Automatic:
The Coil might be wired from the Shore Power, such that the presence of Shore Power AC energises the coil, closing the contacts between shore supply and output to panel.
When there’s no shore power available, the coil de-energises, and the contacts drop open, closing the circuit between Inverter & Panel.

In any case, you’ll have to ring out the contactor and feild wiring.

A “loose” analogy (below):
The diagram depicts a 3∅ reversing motor starter (contactor), where Forward might be analogous to Shore Source, and Reverse to Ship Source. The Motor represents the AC Panel.

[colemj]

I'm with Gord - I think it is an external transfer switch that was used with the (now removed) inverter. Many new inverters have these switches built into them, but the older ones required an external add-on.

Shore power would break the inverter connection to the panel, and the absence of shore power would reconnect the inverter to the panel.

Also, some of the wire looks like solid romex. If so, you might want to consider changing it for stranded wire.

Mark Cole
www.svreach.com

[turkish6]

If it's like Gord said what is my solution. There is no inverter anymore. Do i just connect the wires back together depending on color like Mirco said...

BTW thanks for all the replies

[GordMay]

Trace the wires out, and connect the AC Shore Power Supply wires, to those that go to the AC Panel (Main Breaker).
Make certain that the AC Hot (normally Black) connects to AC Hot, and the Neutral (norm. White) to Neutral, and Ground (norm. Green) to Ground (thru’ Galvanic Isolator, if fitted).
There’s no Voltage to Ground on the Neutral.

[Christian Van H]

It's obvious what we're looking at... a rats nest. The relay is Potter-Brumfield type ( 655-PRD-11AH0-120 ) , and you should be able to find the coil voltage printed somewhere on the relay. If it is a transfer relay, it should be 120 VAC. BTW, how do you know this relay is bad? Did you get a voltage at the coil but no armature pulldown? C