What the heck is this???

[johnjen50]

All,
So I left the boat last week on the hard, unplugged, and noticed these things humming in the generator room as I left, but don't know where the shutoff switch is. I have a 58 yachtfish. I came back to the boat today and the batteries were dead. Can anyone tell me what these are, I have 2 of them in the generator room, and more importantly how do I turn them off so they don't kill the batteries again! Thanks
John

Attachment 14069Attachment 14068

[johnjen50]

Sorry, I couldn't flip the image. These sit on the aft floor in the genny room. Thanks again!

[SKYCHENEY]

Well, they have nothing to do with your batteries. They are 240v isolation transformers.

[johnjen50]

OK, thanks. They buzz even though the power is not plugged in?? I am confused. I thought they were the drain on the battery.

[Canuck Dennis]

Do have an inverter ? maybe some king of backfeed.

[johnjen50]

Just the Newmar inverter in the engine room, no other inverter. They shouldn't buzz when the shore power is not plugged in should they??

[johnjen50]

Ok, so I did a little research on isolation transformers, and have a bit better understanding of what they are. What I don't get is why mine are humming even when the shore power is not plugged in.

[Sailor John]

Can't help, but the company appears to be in business still.
Try going here:
http://www.alliedelec.com/acme-electric-corporation

Sailor John

[johnjen50]

Thanks Dennis and John. I appreciate your help. I'll circle back with what I find.

[Boatnut]

OK, thanks. They buzz even though the power is not plugged in?? I am confused. I thought they were the drain on the battery.

You are correct that they should not buzz when the power is disconnected. Theoretically transformers should not make much noice, in reality they often do. If the ac power to the boat is disconnected, as you say, verify that you still get the buzz when the cords are unplugged. If the buzz still occurs then most likely dc is being applied to the transformer. Verify this with a meter. If you do have dc being applied, troubleshhoting will be needed to find the source of the dc voltage.