# What size Transformer

Discussion in 'Fifth Wheelers' started by IanH, Nov 17, 2010.

1. ### IanH

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Decided to hold of on the 240v conversion for the moment and fit a transformer to use the 110v equipment we have

What size transformer do you use and any recomendations where to get it.

Our last one came from JMS of Peterborough and i see Airlink also do them

Cheers Ian

2. ### scotjimlandFunsterLife Member

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no point in being bigger than the max EHU supply of 16A .. = 3.68kw .. so a 4kw is more than adequate ..

the bigger it is the more nuisance trips on the EHU you will have due to high inrush currents when you first power up .. also consider 'soft start' transformers which overcome this problem.. but at a cost

Last edited: Nov 17, 2010

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is there a table fo the amps = kw?

If 16amps is = to 3.68 kw max

do you have the same for

6 amps and 10 amps?... would be useful to know what we can load on a european site - thanks

Bob

4. ### johng

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Bob I would say 1500W for 6amps and 2500 for 10 amps :thumb:

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If you are going down that route should not some consideration be given to getting a continuous use transformer, as opposed to a site type
Sorry if sucking eggs and Grannies spring to mind
Geo

6. ### scotjimlandFunsterLife Member

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Simple formula to remember Bob

Volts (V) X Amps (A) = Watt

so 230V X 6A = 1.38 kw and 230 X 10 = 2.3 kw

and useful to remember

W = V x A

A = W/V

7. ### scotjimlandFunsterLife Member

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Yes, I would agree, that's why gave the :thumb: to Airlink

however, the one in George was a yellow 3kw site tranny and never gave a problem even when used continuously for three years .. got a tad hot at times..

8. ### IanH

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Airlink has a 5 kva transformer with surge protection ? , with 4 wire conection
120 0 120 earth which matches the 50 amp wiring on the 5er .

Biggest ouch is the price £270 + vat +delivery what do you guys think on the price

Still waiting for JMS to reply but i recall i paid £300 ish for one off them in 2005

9. ### scotjimlandFunsterLife Member

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Hi

why 5kva ? the 4kva is cheaper and is more than adequate ..

or is it because you have a 5kva genny ?

Price , you get what you pay for and Airlink are probably the best ..

10. ### IanH

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I was looking on their site for american motorhomes and the model US5000 was the one that jumped out at me ,they dont list a 4kva

The US5000 only have three wire conection and they recomended WM5120 industrial

Just looked on their site for industrial transformers and see they do a WM4004 4kva with 120 0 120 earth conections a bit cheaper so will phone them tommorrow and see what its all about

Ian

11. ### IanH

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Fitted the transformer today

4 KVA Airlink a very nice unit indeed,everything i tried seems to be working fine and will try the microwave and washing machine tomorrow.