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Author Topic: Converting from US to UK Electrics  (Read 1442 times)

UK-RV

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Converting from US to UK Electrics
« on: February 15, 2007, 10:20:16 AM »

Hi

Ive been sent the attached diagram showing the "easiest" (authors word) way to convert our RV to operate on UK electrics.

Any comments ?

Thanks
Paul

Tom

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Re: Converting from US to UK Electrics
« Reply #1 on: February 15, 2007, 11:00:33 AM »
Paul,

Just a couple of questions:

  • Does the new inverter have both 110V and 240V outputs? It would appear so since it's feeding both the new 240V stuff and the 'old 110V converter'. Do you have a separate converter, or is it built into your inverter? If the latter, I assume you'd still be using the converter part of it?
  • Do the new 240V socket outlets use the existing wiring? Only reason to ask is that you might want to confirm the wiring is rated for 240V. Remove one of the existing outlets and see if you can read the rating on the sheath of the cable. I suspect it's OK (probably rated for 600V).

Otherwise, I don't see why it wouldn't work.
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UK-RV

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Re: Converting from US to UK Electrics
« Reply #2 on: February 15, 2007, 11:08:14 AM »

Tom

1. Dont know
2. Dont know

Given my complete lack of understanding with these things, I guess I was hoping that forum members (like yourself) would come up with the questions I need to be asking of the author/installer.

Does the diagram suggest to you that our existing Inverter will be redundant after the change ? if so, is it something which can be removed (and sold) before we head home ?

Thanks for the help !!
Paul



Tom

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Re: Converting from US to UK Electrics
« Reply #3 on: February 15, 2007, 11:27:11 AM »
Paul,

Re-looking at the diagram, it's not clear what function the existing inverter performs. It shows both the existing inverter and the new transformer (fed from the new inverter) both feeding the existing 110V distribution board. The use of the term 'converter' is confusing in this context. You might wish to ask the author to clarify this.
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Karl

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Re: Converting from US to UK Electrics
« Reply #4 on: February 15, 2007, 11:34:54 AM »
Paul,
Quote
Otherwise, I don't see why it wouldn't work.
I agree with Tom. Unless the existing inverter is dual voltage, 120/240, it would be replaced by the new 240V inverter and become unnecessary and could be sold. The only other consideration I can think of is the 240/120 transformer. It's likely to be quite large and heavy to run the a/c, micro and other devices, so space and heat produced (ventilation) need to be addressed.
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Karl

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Re: Converting from US to UK Electrics
« Reply #5 on: February 15, 2007, 11:37:50 AM »
Tom,
It shows the existing Converter, powered by the transformer, running to charge the batteries. If the new inverter has charging capability, it becomes unnecessary.
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Lou Schneider

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Re: Converting from US to UK Electrics
« Reply #6 on: February 15, 2007, 01:51:00 PM »
This looks like a good plan.  It's very much like my inverter/converter setup, except mine is not dual voltage.  It should work fine within a couple of limitations.

The Onan transfer switch does not backfeed generator power through the 120/220 volt transformer to the 220 volt circuit panel, just as it isolates a 120 volt shore power cord from generator power.   I think we can assume the feed-through transfer switch on the inverter does the same - passing shorepower to the 220 volt outlets when it is available and disconnecting the inverter from the 220 volt shore power circuit panel when shore power is not present.  This means the inverter will not backfeed the 120 volt buss or the original converter - all it feeds are the 220 volt outlets in the rig.

The inverter will provide power to the 220 volt outlets with or without the generator running, within the capacities of the inverter and batteries.  You will have to run the generator to use the air conditioner or microwave.   The refrigerator will switch to gas mode unless you are plugged into shore power or running the generator.

You can use a combination inverter/battery charger with a built-in transfer switch if it's more convenient, but having the extra charging capacity may not be of much use.   Since the input will be 220 volts, the only time the extra charging will be available is when you're plugged into shore power.    If you're going to be plugged into electricity overnight does it really matter if it takes 2 hours or 8 hours to recharge the batteries?

You willl need a new, 220 volt inverter so yes, that does make your existing inverter redundant.  You could salvage your existing inverter by putting a 220/120 volt transformer on the front (mains) side and another 120/220 volt transformer on the outlet side, but this is probably more trouble and expense than it's worth.  And the inverter will put 60 Hz power on your 220 volt outlets, not 50 Hz.

When you're plugged into electricity the 220 volt outlets are fed directly from the shore power via the feed through transfer switch.  But when you're not plugged into electricity, all of the outlet power comes via the inverter, not directly from the generator.   This places a couple of limitations on how much power you can draw from the outlets.

First, the size of the new inverter will determine how much power you draw from the outlets.   A 500 watt inverter won't power a 1500 watt hairdryer, for example.

Second, the inverter power comes from the batteries, which are in turned charged via the original converter.  A 45 amp converter will supply about 500 watts.   If you use less than 500 watts the converter will supply all of the power you're using.  But if you use a higher wattage, say running a 1500 watt hair dryer, the excess power will be drawn out of the batteries and you'll have to run the generator longer to replace it.

I presume the author has a source for the "pass through transfer switch" that will be used with the new inverter, if it is not included as part of a combination inverter/charger.

The only real question I have is how well the 120 volt, 60 Hz components will work on the 120 volt 50 Hz power they will recieve when you're on shore power.  50 Hz transformers have to be about 20% physically larger than their 60 Hz only counterparts and I don't know if the 60 Hz equipment has this much fudge factor in their design.

A modern converter like the Progressive Dynamics should work OK on 50 Hz power.   A converter with a 60 Hz ferroresonant transformer obviously won't.  A 3 way refrigerator probably doesn't care since the only 120 volt component is a heating element.   But I'd question the safety of running the 60 Hz motors and transformers in the microwave and air conditoner on 50 Hz power.  It would be wise to ask the manufacturers whether or not their equipment can tolerate it.
« Last Edit: February 15, 2007, 04:58:43 PM by Lou Schneider »

Karl

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Re: Converting from US to UK Electrics
« Reply #7 on: February 15, 2007, 04:48:59 PM »
Quote
A modern converter like the Progressive Dynamics should work OK on 50 Hz power.   A converter with a 60 Hz ferroresonant converter obviously won't.  A 3 way refrigerator probably doesn't care since the only 120 volt component is a heating element.   But I'd question the safety of running the 60 Hz motors and transformers in the microwave and air conditoner on 50 Hz power.  It would be wise to ask the manufacturers whether or not their equipment can tolerate it.
Good points, Lou. The motors may not run at the correct speed and will certainly get hotter. There are motor/generators that would do the job, but now you're talking big bucks and a lot of weight. There are also solid state freq. converters, but they're pretty expensive too. In the long run, might it not be better to sell the big-ticket items while stateside and retrofit with the proper replacement units when he's back home? Just a thought :-\
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

UK-RV

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Re: Converting from US to UK Electrics
« Reply #8 on: February 15, 2007, 04:58:40 PM »

Phew !!

My head is certainly spinning with all this info now.  :o

Thanks for the replies - and please keep them coming if you think of anything else.

The person Ive approached for the work is at a show for the next 2 weeks, so Ive got time to properly word several questions to put to him on his return.

Regarding the 50/60Hz issue - we know the microwave clock and the washing machine will run slightly slower, but people have told us its been no major problem for them.

Thanks
Paul



 

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