caserta@athena.mit.edu (Francesco Caserta) (06/03/91)
Sometime ago I posted in this group a message about surge suppressors and 220/120V transformers. Richard Schumacher (schumach@starman.convex.edu) sent me this reply: > Do you know whether your equipment can use 50 Hz AC? If the > equipment does not explicitly state that it can accept 50 Hz, > then not only will the equipment not work but it will probably > be damaged and in addition will be a fire hazard (components > will overheat). > Transforming 220 VAC to 120 VAC is easy; it's the frequency > problem that's hard. One can buy converters to convert 220 V > 50 Hz AC to 120 V 60 Hz AC, but they may be expensive. I'm posting it for two reasons: I couldn't get in touch with him for e-mail problems (unknown host), and because I would like to know more. Essentially, I would like to know who produces and/or sells (mail-orders?) these devices, because I never came across with any and I'm very interested. Thanks a lot. Francesco Caserta
wrs@mcshh.hanse.de (Wolfgang R. Schulz) (06/04/91)
caserta@athena.mit.edu (Francesco Caserta) writes: >> Do you know whether your equipment can use 50 Hz AC? If the >> equipment does not explicitly state that it can accept 50 Hz, >> then not only will the equipment not work but it will probably >> be damaged and in addition will be a fire hazard (components >> will overheat). I doubt this very much. These days the only compent which could get a little warmer is the transformer, but usually not to a dangerous extent. After the transformer everything is DC and therefor does not care about what frequency the AC had previously. Other than in the old days, when the power frequency of 60 or 50 Hz was even used to synchronize a TV set (what gives us even today terrible differences in TV standards) was used to synch picture, now everything that vibrates in one kind or'the other is done by calculated circuitries, sometimes chrystal locked. Some VCR's may use the 50 or 60 Hz for their digital clock. In that case you just get the wrong time, but it does no harm. Wolfgang -- ***Wolfgang R. Schulz, Theodor-Koerner-Weg 5, 2000 Hamburg 61, Germany*** ***phone: +49 40 5521878*****BTX: 0405521878*****MCI Mail: 241-2526****** ***Internet:wrs@mcshh.hanse.de**Bang:..unido!mcshh!wrs**wrs@mcshh.UUCP***
jeh@cmkrnl.uucp (06/07/91)
In article <9258@mcshh.hanse.de>, wrs@mcshh.hanse.de (Wolfgang R. Schulz) writes: > caserta@athena.mit.edu (Francesco Caserta) writes: > >>> Do you know whether your equipment can use 50 Hz AC? If the >>> equipment does not explicitly state that it can accept 50 Hz, >>> then not only will the equipment not work but it will probably >>> be damaged and in addition will be a fire hazard (components >>> will overheat). > > I doubt this very much. These days the only compent which could > get a little warmer is the transformer, but usually not to a > dangerous extent. After the transformer everything is DC and > therefor does not care about what frequency the AC had previously. fine so far. Note the word "usually". > Other than in the old days, when the power frequency of 60 or 50 Hz > was even used to synchronize a TV set (what gives us even today > terrible differences in TV standards) was used to synch picture, argh! Never was this the case. What DID happen was that the TV field rate was chosen to be the same as the local line frequency in order to minimize the effect of power supply hum on the picture. > Some VCR's may use the 50 or 60 Hz for their digital clock. In that > case you just get the wrong time, but it does no harm. except that if you have a 60 Hz VCR in a 50 Hz country, you most likely have an NTSC VCR in a non-NTSC country, so the VCR will be pretty much useless anyway. Unless the VCR is a multistandard VCR, in which case I'd expect it to have a switchable 60/50 Hz (or crystal-driven) clock as well. --- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA Internet: jeh@dcs.simpact.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com Uucp: ...{crash,scubed,decwrl}!simpact!cmkrnl!jeh
kwang@polyslo.CalPoly.EDU (<The Scarecrow>) (06/11/91)
In sci.electronics jeh@cmkrnl.uucp writes: >wrs@mcshh.hanse.de (Wolfgang R. Schulz) writes: >> caserta@athena.mit.edu (Francesco Caserta) writes: >>>> Do you know whether your equipment can use 50 Hz AC? If the >>>> equipment does not explicitly state that it can accept 50 Hz, >>>> then not only will the equipment not work but it will probably >>>> be damaged and in addition will be a fire hazard (components >>>> will overheat). >> >> I doubt this very much. These days the only compent which could >> get a little warmer is the transformer, but usually not to a >> dangerous extent. After the transformer everything is DC and >> therefor does not care about what frequency the AC had previously. > >fine so far. Note the word "usually". usually, referring mainly to linear power supplies. Don't even think about doing this with switching power supplies... - Kevin Wang ----------------------------------------------------------------------- kwang@polyslo.calpoly.edu, or kwang@hermes.calpoly.edu New Crossbred ISMs for the 90's Max Headrheumatism. "Wh- wh- where's my Ben GGGGGay?" -----------------------------------------------------------------------
myers@hpfcrlm.HP.COM (Bob Myers) (06/13/91)
>usually, referring mainly to linear power supplies. Don't even think >about doing this with switching power supplies... Doing what? Operating on 50 Hz AC? It's the rare switcher that isn't designed to work on both 50 Hz and 60 Hz AC - "usually," the power supply manufacturer is designing to some range which will cover both standard frequencies plus a generous tolerance; like "47-63 Hz." Why do you think that switchers are especially sensitive to line frequency? (Not that you can't come up with a particular switcher that won't work at 50 Hz with X load, but your reply seemed to imply that switchers were designed for a *very* limited range of input frequencies.) Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not Ft. Collins, Colorado | those of my employer or any other myers@fc.hp.com | sentient life-form on this planet.