Asymmetrical Information

most laptops can deal with both types of power. read the brick -- it should tell you whether on not it's going to work.

as for the other things, well, read their bricks too just in case, but they're much more likely to require 120v.

if you've got one of those tiny convertors (about the size of, say, the linksys brick), you're unlikely to be able to use it with a power strip without melting it. add up the wattages and see. also check to see if the convertor says it's rated for continuous operation -- many aren't.

if you're there for an extended period of time, the best thing to do is to get 240 bricks. in new zealand, they were sold at hardware stores. if you find a friendly one, you can probably just explain your situation to the salesperson -- they can show you what you need.

linksys may also have a uk presence from which you could get a 240 brick. they might not even charge, surprisingly enough.

another thought. before spending money on bricks, consider whether or not you could just buy a replacement for the same or cheaper. clock radios, corded phones (and maybe cordless too) are really cheap these days. a decent cell plan plus a cheap corded phone may turn out to be easier in the long run.

Hey, a reminder, I am going to be in London in about a week and a half, I know that J&R sells universal laptop adaptors that work for all laptops and all plug systems. Want me to pick one up for you. They cost about $100.

I just got back from London yesterday. I would have stopped by to help :-). I'll second Matt's comments. Your laptop almost certainly will run on 240 volts (read the power brick to make sure). Assuming it does, all you need is an adaptor plug that plugs into the UK outlet and has a US style socket on it. I saw a number of these in stores that catered to tourists in London. I got mine years ago online somewhere.

I'm not sure what you mean when you say you have "a converter that can convert 240 volt power to either 50w or 1600w". An inverter would typically be unlikely to have a power rating with two numbers that far apart (and a 1600w inverter would be pretty big). My small 50w inverter is rated for a maximum of two hours continuous use. I'd guess that Matt's suggestion of looking for replacement power bricks for your 120 volt only devices is the way to go.

Since you want to use your cordless phone, you'll need another adapter for the phone cable--the UK uses a slightly different plugs than North America.

Enjoy your time in London--it's a great city! (And New York will look cheap by comparison when you return!)

Jim

I suspect that the "50" you saw was 50 Hz, not 50 Watts. 1600 watts sounds like a reasonable spec for that kind of power converter.

The formula you need to remember is Ohm's Second Law:

P=E*I
watts = amps * volts

There should be a label on the converter somewhere which describes the front-side and back-side power numbers. If you bought it in America, that's required by UL. I would guess that what it will say is that the front side is [240V, 50 Hz, 7 to 8 amps] and the backside will be [120V, 60 Hz, 13.5 amps, 1600 watts]. It may not provide an explicit backside current number (amperes), and if so you'll have to calculate it from the volts and watts using the above formula. But probably the number is about 13 amps.

The power bricks for your gizmos will have labels that give a rating for how much electricity they draw. They will say what voltage they need, the AC frequencies they support (in hertz), and the amount of current they will draw (in amperes). For instance, the brick for my laptop says [100-240V~1.5A(1.5A) 50-60 Hz]. That means it draws 1.5 amps at 100V and also draws 1.5A at 240V. (Which in turn means it's using a honking big regulator and will get really hot when plugged into 240V, but let's not go into that.)

All your bricks will have such a label. The critical number you want from each is the current (in amperes) drawn at the lower voltage level. If more than one current rating (in amps) is given, then the largest value is the important one.

And here we reach the critical point of all this: the rated current of the converter must equal or exceed the sum of the rated currents for all the devices plugged into it.

The sum of the currents for all your power bricks must be less than 13 amps. Given the devices you listed, it's doubtful they draw even half that, so you should be fine.

If the sum of the devices exceeds the converter's rating, you'll blow a fuse or a breaker on the converter. (It shouldn't smoke, but be informed: Smoke Is A Bad Thing. If you see smoke or smell something acrid, unplug the converter from the wall.)

The front side of the converter should be a male power plug compatible with European wall sockets. The backside of the converter should be either a single female American power plug, or it will be a power strip with multiple female American plugs. ("Hot" power plugs are always female, as a safety measure.) If there's only one female plug on the backside, then you should plug a standard American power strip into it. The converter should plug into the wall. Then you can plug in all your American devices into the power strip.

By the way, there's a cheap way and an expensive way to design that kind of converter. The cheap way is just a stepdown transformer, but that means it provides 120V at 50 Hz. The expensive way also changes the frequency.

Any device whose power brick says it requires 60 Hz exclusively shouldn't be used with a power converter which is producing 120V at 50 Hz.

If you plug it in, it may seem to work, but there's a risk that eventually the brick will smoke. (Explaining why requires words like "impedance" and isn't worth going into.)

Most of your power bricks should say that they can handle either 50 Hz or 60 Hz, and if so they'll work fine with a cheap converter. From what you said, I think that's what you got.

More correctly, Seeing Smoke Is A Bad Think. All electronics run on Magic Smoke, and no longer work once it gets out. Checking for escaped smoke was one of my major responsibilities when I was working on industrial control systems. SDB just didn't want to get this technical.

Mr. Den Beste's comments are all quite accurate, and should be studied carefully. The 50w converter is actually a small transformer that changes 240v/50Hx full sine wave power to 120v/50Hz full sine wave power. It produces exactly the power that you desire, but not very much of it (only 50w), so it is only useful for small electronics.

The 1600w unit is a simple diode that changes 240v/50Hz full sine wave to 240v/50Hz half sine wave. It is only useable on items like hair dryers, curling irons, and _maybe_ some toasters (but you have to be willing to perform a destruction test to find out).

I have not seen any laptops that do not accept worldwide power (100-240v/50-60Hz). Most desktops computers and many consumer electronics such as TVs, also have universal power supplies.

If you want to run anything serious, you need to buy a full-size transformer. 250w will run an electric blanket or a small stereo, 500w will just barely run a small vacuum, 1000w will run most small kitchen appliances. The larger they are, the more expensive and heavier.

You CAN run some electric motors at the wrong frequency. They will run at different speed, and may die prematurely, but it may be advantageous to do so. Frequency conversion is not cheap.

If you have any lamps, they are the easiest to use - just change the bulbs.

Oh, and you need plug adaptors for the transformers and lamps, to be able to plug them into Brit outlets. Brit outlets are outrageously designed with internal fuses and sometimes even switches, because of the ring-main distribution system that is used in Brit buildings.

I have heard that Brit hardware shops sell a packaged 240/120v transformer to allow workers to use 110v tools on job sites. Evidently, the Brits think 110 is safer in a construction environment.(?) This would be a good place to start to look for transformers.

I did this when I lived in Paris, and am making plans to rewire a French farmhouse for both 240 and 120 service when I retire, to allow me to take some appliances over that I cannot find in or don't want to buy again, in France (toaster ovens).

Oh, one last item - you mentioned the telephone. It can be powered from your 50w unit, but it may not work with the Brit telephone system. Their system has a different ringing (and I think even a different wiring) system than US phones. I never had any luck making US phones ring in France - you could make calls, but you never knew when someone called. You will have to get a Brit phone. The VOIP box should be able to work off the 50w converter, as should the router, but if you put them all on together, then you may have a problem. Best to get a 250w transformer. DO NOT use the 1600w converter - it will fry them all.

Ralph, bear in mind that even if you wire your French house for 120 VAC, the frequency will still be wrong (50 vs 60 Hz), which could be a problem for older devices that use transformers (which could dramatically overheat). Switching power supplies (as most modern electronics, including computers, use) should be all right, though.

I should add that the wrong power frequency would also be a problem for anything (like a record turntable, for those codgers amongst us) that uses a synchronous motor.

My VOIP box actually has the same sort of converter as my laptop, so the real question is just whether I can put a Linksys Router and a phone off my one converter at 50hz (thanks for the correction) or whether I need two.

I'd buy a transformer, but I'm only here for three months, and on a journalist's salary, just can't justify the expense. Apparently, the thing to do is get one by mail order from India.

And my phone is plugging into the VOIP box, not the BT phone line; the flat came with a phone for that.

Rand,

Thanks for the comment. I understand the issue - I had to change the pulley on my turntable while we lived in Paris. As an interesting datapoint on motors, we bought a French refrigerator in Paris, and brought it back to the US when we came back. We thought we would use it in a basement apartment, but ended up using it full time in a second house, running on 220v/60Hz. It ran fine for 10 years, and eventually went back to the farmhouse in France, where is is still in service. The stove made the same trip, and except for the clock running fast, it also did quite well.

Jane, you need to look at the powersupply label on the Linksys and the phone, for the power requirements. It will say something like 120v/60Hz, 15 watts, or 1.0a (amps). Add up the wattage of the two devices, and if it is less than 50, you can use the 50w converter.

Note that if you have a brick, it may show something like this: INPUT:100-240V~ 1.4A-0.8A 50-60Hz OUTPUT: 16V DC 4A (This is from my Sony laptop). Multiply the 100x1.4 and you will get 140 watts (too much for the 50w converter) DO NOT multiply the output, because that number does not include loss factors, which are important.

These numbers are usually over-rated, for safety purposes, so I imagine that you should be able to plug in both the router and the telephone, but this sort of experiment should only be attempted by a knowedgeable engineer - look around London - you should be able to find one - they look like nerds or old men...

REMEMBER: DO NOT USE THE 1600W UNIT FOR ELECTRONICS!!!

Ralph

With the cordless phone you have taken care of two of the three problems that I could think of. First is the electrical powering issue with a converter. Second is the issue of DTMF/wiring/ringing frequency and voltage with a US style VOIP box. The third, however, concerns the RF frequency of the cordless phone. Depending on its age, it could be any of 900MHz, 2.4GHz, or 5.somethingGHz. These are US license free bands suitable for low power applications. The questions I have are: "What is the frequency of your phone?" and "Is this frequency band legal for non-licensed use in the UK?" Remember in the UK they have TV license police which patrol the area looking for people who haven't paid their BBC tax.

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