Mystery Box in Engine Room

[JLR]

I have a 14” X 18” closed electrical box wall mounted next to my battery charger in my ER on my other boat (56 Ocean). It has three switches on the outside labeled hi/low, on/off and hi/low respectively. I opened the box and found two transformers and a few relays. It has one 110v lead going in and two 12v leads coming out. Any idea what this box is for?

 

[doc g]

low voltage lighting ???

 

[Cricket]

Hello John, how about a photo?

 

[JLR]

Photo is not easy to come by, at least in the near term. The on/off switch has been on since I bought the boat and there is definitely AC coming in and DC going out. Could it be some sort of battery conditioner? Really weird to have those hi/low togles(2) on the side.

 

[SKYCHENEY]

Take a look at your full compliment of wiring schematics that Ocean provides to all Owners. Oh wait, its Hatteras that does that. Nevermind.

 

[JLR]

Any other ideas? The hi/low switches are what throws me.

 

[Boatsb]

Could it be for lights?

A 50 ocean in worked on had 110 volt to 24 volt transformers.

 

[jim rosenthal]

Sounds like lighting. Do you have 24v spare bulbs anywhere?

 

[Nonchalant1]

Just follow the wires.

 

[JD5652]

You could use a Fox & Hound to trace the wiring...

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[JLR]

Lighting makes sense since I do have a lot of 12V lighting. But what are the hi/low switches for on the side of each transformer and why would there be an on/off button on the side as well? Tracing the wires is not in the cards right now.

 

[JLR]

Here is a picture (I hope) inside the box showing the AC input from the bottom and the two DC outputs from the top. The switches (not pictured) are on the left side of the box. Hope this helps figure out what it is. All ideas welcomed.

 

[JLR]

Obviously, there is only one box. Sorry for the double picture post.

 

[dsharp]

they're voltage transformers. They are probably tapping 12 and 24 volts off of them.

 

[Chasemmc]

Disconnect the power to each one in turn and make a list of what doesn't turn on anymore.

 

[drburke]

Some Hatts have isolation transformers with a second secondary winding which automatically (via relay) gives a 10% voltage boost if your marina had too much drop.

Might be a manual version of that. The clue would be a tap at 90% and another tap at 100%.

DAN

 

[jim rosenthal]

I wonder if it's robust enough for that. They don't look all that large.

 

[JLR]

Not likely. The output is 12V not 120V. Some have suggested that this is somehow related to the low voltage lighting on the boat. If so, I am not sure what the hi/lo switches are for.

 

[Boatsb]

12 and 24 volt?

Also many oceans had incandescent lights that were run from 24 volt AC.

You cant use that power with most led lamps.

 

[Reefgeorge]

Its hard to see in this picture but it looks like the switches route different secondary taps on the transformers. Can you measure the voltage on the taps or the switch outputs? Also, a transformer can only step up/down voltage or provide isolation. The conversion from AC to DC requires a rectifier bridge or discrete diodes and filter capacitors or an AC/DC converter board.

George