Help with these Isolation Transformers (assuming that is what they are)

[zigzag930]

I have 2 large boxes in the engine room (see below) which I believe to be isolation transformers as well as possibly voltage boosters/frequency converters.

Of all the documentation I have on board, I don't have any information on these.

I've attached a photo of the top unit and hope maybe someone has them on their Hat.

I've made several calls the Micron and no call backs with assistance yet.

Sure would love to get a copy of the owners manual or ANY information on them.

 

[cww]

What exactly do you need help with? If your shorepower is working, then they're working. They tend to last indefinitely unless something happens to them (surge, get wet, etc.). There are no moving parts that you have to oil or anything like that.

 

[zigzag930]

Well, they are either working or have been bypassed, as I do have 240vac. There are no indicator lights or switches on the outside of the boxes so I don't know if they are still hooked up or not.

I would just like to know what they do and how to configure them if I wind up in an areas of the world where I have something other than 240vac or 60hz.

Are these for isolation? Are they supposed to prevent galvanic corrosion?

 

[Pascal]

I be never seen these. They are labeled “voltage regulator” not “isolation transformer” so who knows. You may want to Open the cover to see if they re connected and what is in there.

Some shore power systems have relays and contactors inside that need occasional service. No idea if that the case with these

 

[johnjen50]

They do buzz a little bit, so you would know they are working if you hear that. If those are actually isolation transformers.

 

[SKYCHENEY]

They do buzz a little bit, so you would know they are working if you hear that. If those are actually isolation transformers.

They also give off some heat. Are they warm to the touch?

I would pull the cover and get out the multi-meter. Do you have voltage on the input and output leads?

 

[zigzag930]

Good questions. I will check that tomorrow and see what I can learn.

This is one of the few remaining items on the boat I have not been able to identify or find a user manual.

 

[chuckbullett@gmail.com]

When you pull the cover to inspect the connections, there may be a schematic glued to it on the inside detailing the terminal connections.



This is a small 30-Amp Isolation transformer I installed for our Electric clothes dryer as the boat didn't come with ISO Transformers on the mains in 1978. I wish it had... I had to "marinize" this transformer from Larson Electronics. Charles Industries used to make a perfect 50AMP Isolation Transformer but alas, they've left the marine sector and are focusing on tele-com.

Best-

 

[zigzag930]

Ok, so one of them is warm and has a nice hum. Only one 50amp shore power is connected, so I would expect only the one transformer (lower in this case) would be active.

I removed the covers. Looks easy enough to convert from 60 to 50hz if I ever need to do that.

I've attached a few photos just in case anyone else has these onboard and is curious.

Still not exactly sure what all they do.

 

[zigzag930]

and one more photo.....

 

[SKYCHENEY]

Looks like its original. I see the Hatteras wire numbers. What do your schematics show?

 

[zigzag930]

Sky, great observation on the Hatteras wire tags. I'm convinced they are factory installed and I was able to reach CD @ Hatteras who confirmed this yesterday. Unfortunately he didn't really know much about them, so couldn't tell me exactly what they do.

I spoke with Micron Industries also. The owner said they made them a long time ago, but would not provide any additional information. Pretty poor that he couldn't at least explain what they do.

Anyhow, CD sent some drawings which show that these (optional) transformers are located between the shore power selector switches and the AC panels on the boat. So, it seems that all AC power, shore, generator, etc will pass thru these transformers.

I see how to convert to 50hz (if that ever becomes necessary) from the information inside.

So I guess these somehow keep the power at 240v even if it dips. I think they may also convert 50hz to 60hz? Still not sure if they do anything for galvanic isolation.

Will have to see if any other LRC owners have them installed and can find the owners manuals.

Thanks to all for the help and suggestions.

 

[cww]

Sky, great observation on the Hatteras wire tags. I'm convinced they are factory installed and I was able to reach CD @ Hatteras who confirmed this yesterday. Unfortunately he didn't really know much about them, so couldn't tell me exactly what they do.

I spoke with Micron Industries also. The owner said they made them a long time ago, but would not provide any additional information. Pretty poor that he couldn't at least explain what they do.

Anyhow, CD sent some drawings which show that these (optional) transformers are located between the shore power selector switches and the AC panels on the boat. So, it seems that all AC power, shore, generator, etc will pass thru these transformers.

I see how to convert to 50hz (if that ever becomes necessary) from the information inside.

So I guess these somehow keep the power at 240v even if it dips. I think they may also convert 50hz to 60hz? Still not sure if they do anything for galvanic isolation.

Will have to see if any other LRC owners have them installed and can find the owners manuals.

Thanks to all for the help and suggestions.

I don't think they were optional unless your boat is pre-1979. Some version of these came on every large Hatteras after that. It's the same setup on my 1980's 53 MY. At least in the later boats, Hatteras used a dual-purpose voltage stabilizer and isolation transformer. Whatever the label on the side says, that's what it does. You can see the transformer blocks in your picture. I was confused about this when I bought my boat too. When I was bringing it back home I stayed at Horn Harbor Marina in Northern VA, and the voltage was all wonky, like +/- 190-200 and the boat just adjusted it to what it wanted all by itself. That didn't help me with the lack of amps, which was also a problem when I tried to run a/c's, but the voltage part was nice. I was thinking what I'm seeing is impossible, until I started reading about it on this site. They do that. I hear a lot of bitching about people who go on trips and either the shore power sucks at a marina they stayed at and certain things wouldn't work, or some appliance or another on their boat isn't GFI compatible and they kept tripping breakers. It's becoming a huge problem down here. I don't know that I would ever go back to not having this setup. It makes shore-power hassle free.

 

[Pascal]

I really don’t think these will convert frequency. It seems to me the input frequency selector is only used so the voltage stabilization works correctly.

Frequency converters installed on boats used in Europe are very expensive.

 

[riverrandy]

This is a super interesting thread for me. I have these same transformers on my 1975 64MY. I assume they were installed to combat poor power input in the Islands. I have gauges on my switch panels that show "pre-transformed power" vs transformed power. See pictures below. What I do not know is if they are Isolation transformers which will help with the new GFCI code regulations a number of new construction docks are required to have. That would be my main question.



though rotated 90 degrees, the photo on top shows meter with pre-transformer and the one on the bottom is post-transformer, or just transformed.

 

[riverrandy]

BTW these things are large. I have put a fluke meter between them for scale.



And finally, my distribution panel showing input for each transformer. I have been able to connect 120v 30 amp to one, and 240v 50 amp to the other for High usage needs with out having 2 50 dock power.



I cannot for the life of me figure how this site changes photo orientation!

 

[zigzag930]

RiverRandy, these are the exact same panels I have in my pilothouse.

I actually never noticed that the breakers are labeled "Transformer 1" "Transformer 2" until just today.

I'm hoping someone out there has a owners manual for these that they can scan and share.

I do have the wiring diagram for the AC shore power if you need it.

BTW, our LRC is '77 so maybe before they became standard?

 

[zigzag930]

Now I understand the rotary switch under the voltage meters. SL "Shore line" or "transformer" voltage readings. I will have to try it and see what I learn.

 

[SKYCHENEY]

I'm not sure about these but The Jefferson Electric transformers do not boost. They are simply for isolation. That was the standard that you see on most Hatts from 1978-90 or so. I have added boost switches so some of those units and that works well. I'd be interested to see if these transformers are auto-boost.

 

[JD5652]

I have similar transformers in my 1976 LRC. Mine are isolation/Buck-Boost design. I also have a selector switch on the front of mine where I can select either Boost (voltage increase) or buck (voltage decrease).

I will get photos of mine and post up next time I'm at the boat.