alford@ecsvax.UUCP (Ross Alford) (07/15/86)
Several weeks ago I posted a note asking in general about what problems might exist in running electrical and electronic equipment designed for 110v 60Hz AC on the 220v 50Hz AC that exists in many other countries. Quite a few people responded in netnews, and I thank you for the effort. Several more responded via mail, and were also very helpful. Their responses, edited to remove identities and extra lines but otherwise intact appear below. I hope that no-one who responded via mail is offended at not being credited: in fact, it was deciding what to do with attribution of the mail responses that delayed my followup posting. I finally decided that removing identities is the lesser evil: if someone wanted to respond publicly, they could have done it in news. Thanks to one and all again...I have a much better feeling for the problem now, and am going to buy 2 or 3 step-down transformers. net responses follow: -------------------------- Note one other problem you might have, the power connectors vary from country to country so besides the stuff below you need adapters so you can plug it in. There are about three classes of devices you have to worry about, 1) voltage dependent devices 2) frequency dependent devices and 3) waveform dependent devices. Class 1) are things like heaters or light bulbs, here as long as the voltage is about right they don't care even if they get DC. The little converter devices work for these. Class 2) are devices like constant voltage transformers which are resonant at 60Hz. For these 60 Hz is an absolute requirement and at the correct voltage. Not much hope for these they must have 120V 60 Hz, but this kind of stuff is rare. Class 3) are things with transformers. Here you have to have the voltage about right and it should be a sine wave or the transformer gets very warm. A stepdown transformer will usually make these work. Sometimes the little converters just put a diode in the AC line and this gives you funny shaped waves that are ~ 120V high. Here lightbulbs and things with AC/DC motors (like shavers) would do just fine. Things with transformers would not work at all since the waveform has a net DC component and transformers are sort of DC shorts. Most modern electronic equipment like computers have switching power supplies and in a lot of cases all you have to do is move a jumper, get a new power cord and it works just fine at 220 V 50 Hz. With one exception this works, if the fan in the box is 120V 60Hz it won't be too happy. In this case a stepdown transformer (very easy to find in Europe) would work OK. The fan would run 1/6 slower but the switching power supply would be happy 50 Hz. Equipment designed for use on both sides of the Atlantic usually has D.C. fans driven from the main switching power supply, here moving the power supply jumper also takes care of the fan so everything works. For small transformer stuff like chargers you have to run them from stepdown transformers but they have no trouble with 50 Hz. Chargers from folks like HP and others sometimes even have a 120/220 switch built in them. You still need an adapter so you can plug them in but no step down transformer. On monitors I have no personal experience but from doing the opposite (using European Monitors here at 60 Hz) it will probably work. You will need stepdown transformers for the monitors . --------------------------- I can tell you that my NiCad battery charger (110 volts) works just fine off of a bottom-of-the-line Radio Shack voltage converter plugged into the local 220v/50hz. Also my contact lens sterilizer (heater type). Those are the only plug-in devices I brought with me, so I can't help you with anything else. --------------------------- My experience, based on using a KayproII and a Compaq in Germany and talking to other people in similar situations: Ignore the cycle difference. Everything is being converted to DC first, so only the voltage difference matters. You can't use the inexpensive light-weight converters. You need a step-down transformer, obtainable locally abroad if not here. Better yet, buy dual-voltage equipment! --------------------------- Seeing as I've been living in Germany for the last 2 1/2 years with a pile of 110v/60Hz stuff in my house, maybe I can shed a little light. Little stuff like AC/DC converters or battery chargers -no problem. I've been running them off of a 1000W step down transformer (with an outlet expander) alongside my two VCR's (110/60), Sharp TV (110/60) and various other gizmos. As far as I know, the only things that you have to beware of are AC motor appliances (fans and clocks) and electronic devices that use the AC frequency for timing - some computers fall into this category, but NOT very many. The only thing that 50 Hz would do to a monitor set for only 60 HZ is make it flicker. Wait. Let me ammend that: I'm sure that there are *some* monitors somewhere that would have real problems with 50 Hz. Better to check on the specific monitor first. Some of the color monitors, though, are "smart" and accept any input voltage and frequency - IBM Color Monitor is one of them. Last item: I have seen a 110/60 printer running off of a stepdown transformer/50 Hz burn out its printhead; however, the owner had it running for 6 hours a day *continuously*. It is recommended that your printer be set for 50 Hz, though. P.S. - About the travel converters: I've never used them, so I don't know. It seems to me that I remember some mention of the (alleged) fact that the heavier stepdown transformers offer some sort of line filtering and/or minor surge suppression. All I know is that whatever you use, you should plug in the transformer, turn it on, plug the devices into the transformer, then turn on each device. NEVER use the transformer as a power-on switch for your entire setup or a nice, fat surge could zap everything. That's all... --------------------------- It would take great skill and dedication to design a simple battery charger that would work at one frequency and not the other, so that would probably work fine. It is my understanding that most video monitors use the line frequency to generate either driving voltages or synchronization signals or both, so there could well be a problem. You might still get a picture, but with something wrong with it. I don't know whether or not there is any risk of damaging the monitor. Makers of computers and monitors for use in Europe usually make versions compatible with a European broadcast standard (i.e. PAL, which uses a 50 Hz field rate). Regulated power supplies may be affected by requiring larger capacitors for a given level of ripple. Devices containing electric motors are normally frequency-sensitive, unless you are sure the motors are running on filtered DC. Your best bet for any doubtful piece of equipment is to contact the manufacturer or find a knowledgable sales representative. --------------------------- Usually 60Hz appliances will work with 50Hz current. Small electronic appliances will usually work since most of them convert the current to DC. TV's and monitors have a much higher probability of not working. --------------------------- I am writing to you in hopes that you will not make the same mistakes I did, I have discovered things the hard way. Quite frankly Franzus stuff (expletive deleted)! To answer your question, no. The Franzus converters use a SCR to try to tame the voltage down from 220 to 110, but they dont give you the full wave form of ac current, only half. I blew out a stereo amp and a CD player. It appears that the things most affected are semiconducter devices. I strongly recommend that you avoid this type of converter. I cannot answer this question exactly but I know that *some* monitors look to the line freq, but most donot. Almost In every machine I can think of, the input current is rectified (made DC) and from there on talk of freq is meaningless. The types of machines that 50/60 Hz does make a difference on is those with AC motors in them, these *will* burn out with time if you use them on 50 Hz. FYI: I am using an AT in the 220V/50Hz mode (red switch in the back) that originally came from the US. But I am using the monitor (EGA) on a Step-down transformer, as there was no easy way to change the voltage requirements. Note that the transformer will *not* change the frequency. Pay the money, you'll be glad you did... -------------------------- Again, I thank everyone who responded. This was the most helpful set of responses I've received to a question asked on the net. Ross Alford ...mcnc!ecsvax!alford Disclaimer: The opinions expressed above are not those of my employer or of NCECS. They aren't even mine--I'm just relaying them.
dh@vax135.UUCP (David N. Horn) (07/18/86)
Some turntables run off a synchronous motor, in which case changing between 50 & 60 Hz will alter the speed of rotation, even if you adjust the voltage with a transformer. Dave Horn, AT&T Bell Labs, Holmdel, NJ. vax135!dh