Disadvantages of using a 220V converter for 110V electronics?

January 11, 2005 12:45 PM

Voltage query: What are the disadvantages of regularly using electronics made for 110V using a step down voltage transformer in a 220V - 240V country?
posted by riffola to (14 comments total)

is it the same frequency? if not, some things work oddly (some electonic clocks, for example, and i've heard rumours about microwaves). but otherwise, nothing i know of - i work with a bunch of (n) americans in (s) america who live on a compound containing houses shipped from the states, with step down transformers (it's 220-240 here), white goods, cars, etc etc...
(there might be practical problems like getting hold of sufficient transformers, of course)
posted by andrew cooke at 1:02 PM on January 11, 2005

There are no problems associated with running equipment off step-down transformers, except for frequency-sensitive stuff (some clocks etc.) since usually 220-240V is at 50Hz, while 110-120V is at 60Hz.

Note that everything runs off of step-down transformers, they generally reside in those big grey cylinders on the side of the transmission lines going into your neighborhood, or big green boxes by the curb in suburbia.
posted by defcom1 at 1:08 PM on January 11, 2005

incidentally, you should get cleaner power. the transformer should be great at killing spikes (i think!).
posted by andrew cooke at 1:11 PM on January 11, 2005

probably a 3-4% of power is lost as heat due to transformer inefficiencies.
posted by skwm at 1:17 PM on January 11, 2005

When I was young, I had a 110V 60Hz humidifier running in my room (next to the bed), plugged into a transformer, which was plugged into 220V 50Hz power. In the middle of the night, I woke up to find the humidifier in flames. Luckily the fire did not spread to the bed or anything else, but it sure scared me. Be careful.
posted by Prawn at 1:51 PM on January 11, 2005

It's no trouble, in general.

However, 50 Hz power means the transformer is less efficient , and therefore needs to be larger to compensate. Basically, this means the transformer in 60 Hz items may heat up too much. Quite unlikely, but for very marginal equipment, it might be a problem.

And yes, there can be a clock issue if the electronics directly use the frequency to some effect (to time things, etc).

Motors that directly use the electricity could malfunction. I wonder if that was Prawn's problem. That and it's a humidifer. Any device that sucks down that many watts is unlikely to be plugged into a properly rated transformer.

A neat side effect of using a power transformer is isolation. Technically, you could touch either side (but not both!) of the output of the transformer and not get shocked. DO NOT DO THIS AND FIND OUT I'M WRONG. :-)

Of course, you need to be sure the transformer is powerful enough for your items (I have seen 1500 watt transformers that would work on a microwave, but... I've never seen someone spend $200 for such an item, never mind find two people to lug it around [they're VERY big and heavy] -- perhaps that's why the microwave is screwing up?)
posted by shepd at 1:54 PM on January 11, 2005

If the electronics use an AC to DC adaptor or have a removable plug, there's a decent chance they can take 240V anyway. Check your specs.
posted by zsazsa at 2:03 PM on January 11, 2005

shepd has it right. One thing that hasn't been mentioned is video. NTSC is 60Hz and PAL is 50Hz simply because of the AC line frequency. I don't know about new TVs, but older TVs and VCRs used line frequency as an integral part of their operation.

And yes, check your specks, you would be amazed at the variety of equipment that just plugs into the wall anywhere in the world nowadays.
posted by Chuckles at 2:19 PM on January 11, 2005

Thanks for the info. Stuff like cellphones and MP3 players have built in transformers in their power cubes, the reason I need to get one for my mom this time is because I tried looking for a decent 220-240V cd clock radio system for her, and there were none to be found in NYC, um at least none made by Coby, so I just wanted to make sure that if I get a properly rated transformer, it'll be safe her to use it.
posted by riffola at 2:47 PM on January 11, 2005

I don't know about new TVs, but older TVs and VCRs used line frequency as an integral part of their operation.

I have been told by an electronics engineer that this is not the case with new TVs. Can't verify that 100%, but that's what I've been told.
posted by wackybrit at 4:10 PM on January 11, 2005

I have been told by an electronics engineer that this is not the case with new TVs.

It has never been the case, as far as I know. The idea of matching the mains frequency is so that appears in the same position on the screen, rather than moving. They still have an independent 50 or 60 Hz oscillator for scanning.

(of course TVs from one part of the world probably won't work in another, and there's no guarantee the TV's PSU will accept a different freq anyway, etc etc)
posted by cillit bang at 4:23 PM on January 11, 2005

I have seen the small travel transformers go bad on 2 separate occasions and let the magic smoke out of equipment. This is likely what happened to prawn's humidifier. You can buy better ones from an electrical supply company, but they tend to be pricey. Radio Shack sometimes carries a model that is a little more heavy duty than the travel adapters, but it is not on their website and not in all stores. I believe it was ~$50-$60.

Also, I have bought at least 3 of these travel converters that did not work at all, so it is a good idea to test them with a meter before using them.
posted by Yorrick at 5:35 PM on January 11, 2005

cillit bang: It has never been the case, as far as I know.

I found this, which pretty much agrees with you. It looks like the first black and white TVs did use the mains frequency for field timing, but that practice ended a long long time ago.

I was pretty sure TVs in the last 10-20 years didn't use line frequency, but I didn't know the practice ended that long ago.
posted by Chuckles at 6:20 PM on January 11, 2005

I use heavy transformers for a number of things. My amplifier needs a heavy transformer, and I still have an old griddle from the States I use for pancakes. I use smaller transformers for lighter things (music equipment). I was fortunate to be gifted with a set of heavy transformers by an American moving back. They are worth hundreds of dollars each!

Brookstones sells an 85watt travel converter that is very good (at least they did in 1998, when I left).

Mostly the hassle over 50 vs. 60 cycle current is a thing of the past.

Transformers left plugged in but without anything running still consume power, so disconnect them from the power supply when not in use!

SOMETIMES plugging in a heavy (1kWatt or more) transformer, with no load attached, will pop a cirtcuit breaker. Plug the load into the transformer before connecting the transformer to the power supply!
posted by Goofyy at 12:54 AM on January 12, 2005