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[Rockhoppers]

Charles, thanks for that, do you have any more info on the rating of the Capacitor...and any other instructions

I have a good friend who is into all that stuff and could do it for me if i can tell him what needs to be done...

Take it X10 must do this themselves when they make a unit for the 240V market......?

Cheers

Andrew

[Charles Sullivan]

Charles, thanks for that, do you have any more info on the rating of the Capacitor...and any other instructions

I have a good friend who is into all that stuff and could do it for me if i can tell him what needs to be done...

Take it X10 must do this themselves when they make a unit for the 240V market......?

Cheers

Andrew

You want a 0.1 microfarad "Class X2" cap - these are designed to open circuit if they fail.

Here's one that's used by many folks as a signal bridge for split-phase AC in the USA:
   http://www.panasonic.com/industrial/components/pdf/abd0000ce29.pdf

The voltage across the cap will be the difference between the primary and secondary transformer voltages, or 240-120 = 120 V,
so the 250 VAC rating is sufficient.

Make sure your "transformer" is really a true transformer and not some switch-mode solid state gizmo.  The 30-50 Watt "Travel Voltage Adapters" you see are usually autotransformers, which are fine for this application.  (Just don't. plug in a big light bulb or anything like that.)   If you can open the transformer housing and there's enough room inside for the cap, you eliminate the hazard of outside wires which could be kicked loose and short out to something.  Temperature shouldn't be a problem as interfaces like a CM15A or a TM751 Transceiver draw only a few Watts.

X-10 modules usually don't have a transformer power supply, just a capacitive voltage divider.  They change a few component values for 240 V operation.

[Rockhoppers]

Thanks Charles

Do i need just the one cap or do i need to put one on each phase, both live and neutral, or just the one of them.

OR

Is there a certain type of transformer that i should look for that does not cause these probelms.

Thanks again

Andrew

[Charles Sullivan]

Thanks Charles

Do i need just the one cap or do i need to put one on each phase, both live and neutral, or just the one of them.

OR

Is there a certain type of transformer that i should look for that does not cause these probelms.

Thanks again

Andrew

Before I answer, let me ask what kind of transformer you have now.   Is it a commercial adapter with a plug for your UK mains and a built-in (or plug-in adapter) North American socket for the CM15A?  Or something you wired up yourself?  What is the Wattage or Current rating?  If it's a commercial adapter, can the information about it be found on the Web?

And do you (or your friend) have a multimeter which can measure AC voltage?

(I don't want to give you erroneous information which could lead to a hazard.)

[Rockhoppers]

Does this help ?

http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=19413&doy=26m1#spec

Andrew

[Charles Sullivan]

Does this help ?

http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=19413&doy=26m1#spec

Andrew

Yes.  This is _most likely_ an autotransformer (which would be good).   From the weight, does it feel like it has a hunk of iron inside (as opposed to just a PC board)?

Now comes the tricky part - can you open the enclosure?  (Many of these require a special screwdriver or are permanently sealed.)

[Rockhoppers]

It is heavy, and has a big chunk iron in it i assume.....

Can get it open if i have to, not tried it yet.... but it has four casing screws.

Andrew

[Charles Sullivan]

It is heavy, and has a big chunk iron in it i assume.....

Can get it open if i have to, not tried it yet.... but it has four casing screws.

Andrew

Looking good so far.   If this is an autotransformer (and _probably_ even it's a dual winding transformer), there ought to be a common connection between the UK mains plug neutral and the USA socket neutral.   The USA neutral is the longer of the two blade slots - the one on the left when looking at it so you can read the manufacturer's name on the front.  Don't confuse this with the Ground, which is the round hole in the USA socket and which will invariably be connected to the Ground on the UK plug.

You'll need to determine if there's enough room inside the housing for the capacitor without it being squeezed against something else.

If the neutrals are common and the capacitor will fit inside, then you'll connect the capacitor between the USA socket hot (the shorter of the two blade slots) and the UK plug hot.  Make absolutely sure that there's no bare wire which could short against the transformer iron or other wires if the capacitor should rattle around when the adapter is jostled.  (Remember that the adhesive on a lot of plastic tape may  tend to dry out and come loose after a while.)

Let us know how this works out.   If satisfactory, there are undoubtedly others in the UK who would appreciate step-by-step instructions and sources of supply for the parts you used.

[Rockhoppers]

Right, got this thing open and it has two wires from the L and N on the UK side going to a wound core in the middle of a large block of iron, it then has two wires comming from the other side of the wound core going out to the USA side, there does not appear to be a common wire.

Should the Cap still bridge the UK to USA live side ?

Mmmmm ?

Andrew

[Charles Sullivan]

Right, got this thing open and it has two wires from the L and N on the UK side going to a wound core in the middle of a large block of iron, it then has two wires comming from the other side of the wound core going out to the USA side, there does not appear to be a common wire.

Should the Cap still bridge the UK to USA live side ?

Mmmmm ?

Andrew

You'll need to check continuity between the primary and secondary windings with a multimeter.  It's still possible this is an autotransformer and the same common wire is brought out twice for manufacturing considerations.  If the resistance between the UK neutral and the USA neutral is in the Megohm range or higher, then it's instead a dual-winding transformer and you might need two capacitors, one between the two lives and another between the two neutrals.

[Rockhoppers]

Ok, let me see if i can get this across to you in words that make sence.

There is continuity between the US Neutral and the UK Neutral,  tested using the multi meter continuity tester.

There is nothing on the Live side, however I get a reading of 200 ohms across UK live to US live, and 70 across US live to US neutral !

There is also a reading of 76 US Neutral to UK Neutral

does any of that make sence ?

Andrew

PS i have two caps anyway !

[Charles Sullivan]

Ok, let me see if i can get this across to you in words that make sence.

There is continuity between the US Neutral and the UK Neutral,  tested using the multi meter continuity tester.

There is nothing on the Live side, however I get a reading of 200 ohms across UK live to US live, and 70 across US live to US neutral !

There is also a reading of 76 US Neutral to UK Neutral

does any of that make sence ?

Andrew

PS i have two caps anyway !

If when you say "There is nothing on the live side..." you mean an open circuit between the UK Live and UK Neutral,  that doesn't make sense in line with your other readings.  But the fact that you do have continuity between the two neutrals probably means you can get by with one capacitor between the US Live and the UK Live.

Can you can _safely_ connect the capacitor with clip leads and try it out with the CM15A while the adapter is disassembled?

(If the adapter is reassembled without modification, the live on the US plug can usually be accessed for testing by not inserting the plug all the way into the socket, but I don't know if that's possible with the standard UK plug and socket.)

[Rockhoppers]

Ok, have istalled one of the Cap's and have not found there to be any difference.

Still can't talk to and wired components

Should i instal the other cap too ?

Andrew

[Charles Sullivan]

Ok, have istalled one of the Cap's and have not found there to be any difference.

Still can't talk to and wired components

Should i instal the other cap too ?

Andrew

Yes.  It won't hurt and can only help.

BTW, did you check the voltage between the US Live and UK Live?  It should be no more than 120 VAC.

[Edited]  Scratch all the above.   Do you have any other US modules besides the CM15A?  We should really first verify that X10 signals will control another US module connected on the US side of the transformer.  A US appliance module would be ideal for this because you could hear the relay click without having anything plugged into it.

[Rockhoppers]

 

It works, you are a genius !

Many thanks !

Just need to set the code on the LM15U away from A1 which it is set to now.

Andrew