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From: jeh@cmkrnl.uucp
Newsgroups: sci.electronics
Subject: Re: 220V/120V transformers with 60Hz/50Hz converters
Message-ID: <1991Jun7.022851.84@cmkrnl.uucp>
Date: 7 Jun 91 09:28:51 GMT
References: <1991Jun3.021343.24148@athena.mit.edu> <9258@mcshh.hanse.de>
Organization: Kernel Mode Consulting, San Diego CA
Lines: 36

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
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