Hater isolation transformer

[bigcol]

Think about buying is isolation transformer 

as I have had galvanic isolators

 

is this a good item to have on the boat please before I buy?

[rusty69]

Also worth looking at these 

https://airlinktransformers.com/category/boating-transformers

[bigcol]

Is £150 a good price.if I managed to get it?

Rusty69 i have had a look at the link before, it's just this come up, wanted £250 for it.

trying to google the make at the noment

also would it be a better buy than just getting a Gavlonic isolator?

 

col

 

[OldGoat]

A serious question -

What's 'wrong' with a properly designed and built GI unit?

Reason - the need to isolate shore power from your boat is important for people with boats on the salty stuff where the salt / brackish water acts as quite a good electrolyte to act as a battery. The canal system is nearer fresh water and if you're on a river then there's even less conductivity. The need also arises because some systems are poorly designed and maintained - but is this true of UK installations?

 

[bigcol]

Lol

Im only going on posts I've been reading on the forum.

We have another Barge project my son in laws working on for us.

And don't know which unit to buy

col

[nicknorman]

Do you have a link to the spec?

 I notice it is 3kVA which is less than 16A

Edited September 12, 2017 by nicknorman

[bizzard]

Electric eels are isolation haters.

[OldGoat]

Between the two, I suspect it's a matter of:

• Choice
• Cost
• Space
• Capacity

 

• Both do the same job
• A GI is cheaper - even more so if you go for a larger unit
• A 'barge' has more space to put a transformer, but would you need more than 3KVa?

There's an article here:-

http://shop.pkys.com/Isolation-Transformer-or-Galvanic-Isolator--which-is-preferable_b_37.html

I guess there's no absolute answer.... 

 

 

[nicknorman]

58 minutes ago, OldGoat said:

Between the two, I suspect it's a matter of:

• Choice
• Cost
• Space
• Capacity

 

• Both do the same job
• A GI is cheaper - even more so if you go for a larger unit
• A 'barge' has more space to put a transformer, but would you need more than 3KVa?

There's an article here:-

http://shop.pkys.com/Isolation-Transformer-or-Galvanic-Isolator--which-is-preferable_b_37.html

I guess there's no absolute answer.... 

 

 

The issue with a  3kVA transformer is that it is plugged into bollard with a 16A breaker. You would therefore have to have some means to ensure that the boat had protection to limit the total current to 13A.

It's better just to use the right thing for the job, which would be a transformer rated at 16A / 3.5kVA 

Edited September 12, 2017 by nicknorman

[WotEver]

58 minutes ago, OldGoat said:

There's an article here:-

http://shop.pkys.com/Isolation-Transformer-or-Galvanic-Isolator--which-is-preferable_b_37.html

One point from that article... "Modern galvanic isolators are almost always of the "fail safe" kind. "

No they're not. The more expensive ones might be but the cheaper ones definitely aren't. 

If you do buy a GI then ensure it complies with the ABYC standard. 

Lastly yes, there is an absolute answer when considering protection from stray current Corrosion (which is why you'd be fitting one). An IT is superior to a GI every time, there is no 'discussion' required. An IT though is of course larger, heavier and more expensive. 

Tony

3 hours ago, OldGoat said:

What's 'wrong' with a properly designed and built GI unit?

Nothing.

Is an IT a superior solution? Yes. 

[Onewheeler]

It's got a soft starter which is very useful with a large transformer.

[GUMPY]

its in a metal case which is a no no on a boat.

On a boat it is not possible to ground an IT in a metal case in a satisfactory manor.  This is the reason the airlink is in a plastic case.

Just so you are aware the case and interwinding screen should be grounded to the supply this immediately introduces a shore side ground onto the boat with all the galvanic problems this can cause in the event of a fault. 

J

 

[ditchcrawler]

So where is it going to be mounted, it should be on shore but that is not very practicably so the only weak point is the cable from the shore to the transformer. I notice that it has an earth terminal on the mounting plate, is that for the incoming shore supply earth connection or the isolated earth connection as the transformer looks as if its bolted to it. Also the voltage is 230 volts (2 X 115) so is it centre tapped.

 

Julian can type quicker than me, I was coming to double insulated, plastic cased.

Edited September 12, 2017 by ditchcrawler

[bigcol]

6 hours ago, nicknorman said:

Do you have a link to the spec?

 I notice it is 3kVA which is less than 16A

I've bought it

£140

I only have the photos, but it came of a barge

promised it looks like new

i am googling at the moment

but the make is well known on google for electrical boat items

 

[WotEver]

51 minutes ago, Onewheeler said:

It's got a soft starter which is very useful with a large transformer.

It's probably just a thermister. The Airlink has one too. I suspect they probably all do these days. 

16 minutes ago, Loddon said:

its in a metal case which is a no no on a boat.

On a boat it is not possible to ground an IT in a metal case in a satisfactory manor.  This is the reason the airlink is in a plastic case.

I'm not keen on metal cased ITs either. When they're mounted on a boat the case is wired to the output earth. The inter-winding screen is usually connected to the incoming earth. Neither of those are a great idea IMHO. 

Edited September 12, 2017 by WotEver

[bigcol]

Ok

I thought it was a bargain!!

there were a good lot of watchers, I know because I put a offer in, and eBay told me I had 11 x competition.

unless it was the forum lol

i just went for it!!!

now we're talking about metal cases

 

[WotEver]

Just now, bigcol said:

now we're talking about metal cases

You asked me about this in PM Col, and i said I wasn't keen on metal cases and pointed you to the Airlink then. 

It'll be fine though