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Isolation transformers

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Wrinkley Community Regular

Wrinkley

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Hi All

 

Its now time to think about protecting the boat hull from stray current. I was going to fit a galvanic isolator until I read the Smartgauge page on the subject and now think I should fit an Isolation Transformer. But which one? There is the Victron Isolation Transformer. 3.6kvA one for around £600 or the Carroll & Meynell 3.3kva £132.75 from Srewfix (43658 pg354)there may well be others. As I don't believe price determines quality or fit for purpose I am very tempted to go for the Srewfix one. Any thoughts or comments would be most welcome.

 

Regards

 

Wrinkley

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alan_fincher Veteran II

alan_fincher

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........or the Carroll & Meynell 3.3kva £132.75 from Srewfix (43658 pg354)........

 

Unfortunately that doesn't seem to be a mains isolation transformer - I thought it sounded cheap!

 

That is, I believe, a transformer that allows 110 volt "site" equipment to run from 240 volt mains.

 

My guess is, (but I'm no expert), that it doesn't even isolate. It is probably what's called an "auto-transformer", meaning that the voltage is derived from one shared transformer winding, so it may still well be electrically connected to the 240 volts.

 

I could be wrong on that, but do not believe this to be able to serve the purpose of a boat's IT, to run normal mains equipment.

 

(Now awaits being told he is wrong!....)

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Gibbo Veteran II

Gibbo

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(Now awaits being told he is wrong!....)

 

You're partially wrong :)

 

You're right in that it is 110 volt, but you're wrong in that it will be isolated from the incoming 230 volts (the centre tapped earth means it has to be).

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Robbo Veteran II

Robbo

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Its now time to think about protecting the boat hull from stray current. I was going to fit a galvanic isolator until I read the Smartgauge page on the subject and now think I should fit an Isolation Transformer. But which one? There is the Victron Isolation Transformer. 3.6kvA one for around £600 or the Carroll & Meynell 3.3kva £132.75 from Srewfix (43658 pg354)there may well be others. As I don't believe price determines quality or fit for purpose I am very tempted to go for the Srewfix one. Any thoughts or comments would be most welcome.

 

Airlink has a good name on this forum (nearly as much as the Whale Gulper!) http://www.airlinktransformers.com/transformer/wp3231-weatherproof-transformer.asp

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alan_fincher Veteran II

alan_fincher

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....but you're wrong in that it will be isolated from the incoming 230 volts (the centre tapped earth means it has to be).

Yes, I had my doubts.....

 

I am correct though, I think, that something that just let American 110V equipment run on our mains is usually just an auto-transformer, with no electrical isolation.

 

I should have been wise to the bit you point out.

 

Still not what OP needs, though, is it ?

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WotEver Veteran II

WotEverDonate to Canal World

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Airlink has a good name on this forum (nearly as much as the Whale Gulper!) http://www.airlinktransformers.com/transformer/wp3231-weatherproof-transformer.asp

That would be my recommendation. It even has a soft-start thermister. Ensure you wire it as per Gibbo's diagram, not how Victron wire theirs.

 

Tony

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bottle Veteran II

bottle

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My thoughts:

 

Isolation transformer if the boat is normally marina based for the major part of the year and connected to to shore line.

 

Galvanic isolator , if you are like me a continuous cruiser and may only use a shore line now and a gain.

 

No logic other than I do not want to spend £600 on something that may never get used.

 

My thoughts:

 

Isolation transformer if the boat is normally marina based for the major part of the year and connected to to shore line.

 

Galvanic isolator , if you are like me a continuous cruiser and may only use a shore line now and again.

 

No logic other than I do not want to spend £600 on something that may never get used.

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alan_fincher Veteran II

alan_fincher

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If you are thinking of going the isolation transformer route, there has been much previous discussion about whether it can be on the boat, or should actually be located ashore.

 

Each has implications, and some strict rules need to be followed if it's "aboard", I think, but I don't remember exact details.

 

Discussed in (amongst others I guess!) this former thread

Edited by alan_fincher
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WotEver Veteran II

WotEverDonate to Canal World

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If you are thinking of going the isolation transformer route, there has been much previous discussion about whether it can be on the boat, or should actually be located ashore.

Ideally, it needs to float about a foot above the ground, equidistant between the boat and the land.

 

Sadly, that's not possible in this universe.

 

Tony ;)

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Wrinkley Community Regular

Wrinkley

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Hi All

I am not a boat builder, well other than my own. I am just trying to fit the best stuff I can suitably for most eventualities. I will be trying CC but may be marina based for winter with a shoreline, just depends how it all goes. So best I fit an Isolation transformer. The airlink works out at £330.60, much better than £600ish. Thanks for all the help.

 

Wrinkley

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Robbo Veteran II

Robbo

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I am not a boat builder, well other than my own. I am just trying to fit the best stuff I can suitably for most eventualities. I will be trying CC but may be marina based for winter with a shoreline, just depends how it all goes. So best I fit an Isolation transformer. The airlink works out at £330.60, much better than £600ish. Thanks for all the help.

 

Mine didn't come with any kind of installation instructions, but here's a link to there site wiring diagram http://www.airlinktransformers.com/technical-fitting.asp?data=11

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