cim2@pyuxv.UUCP (Robert L. Fair) (04/22/87)
A recent article asked about moving a PC to a 220V/50hz country. Transforming from 220V down to 120V is no problem - just ensure that the power transformer is adequately rated. However, changing the voltage does NOT change the frequency, and this can cause many problems (I discovered this when I moved from the UK, a 220V/50hz country) Specifically many electronic devices use the line frequency to provide a timing reference, if this changes timing goes wild, for example my hifi turntable started going 15% faster when I came here - even though it was a 120/220V model. For PC's, the most likely candidate for frequency problems is the monitor: some monitors generate the scan/retrace rate from the line frequency, which causes a most unpleasant 'swimming' effect on the screen. Again, some monitors use an internal clock which is independent of line frequency, so no problem would arise. I hope this is some help. Rob Fair ihnp4!pyuxv!cim2
wb8foz@ncoast.UUCP (04/28/87)
> Article <275@pyuxv.UUCP> From: cim2@pyuxv.UUCP (Robert L. Fair)
# A recent article asked about moving a PC to a 220V/50hz country.
Mr. Fair commented about motor speed and sync problems.
First I cannot believe his turntable sped up, not slowed down.
But more importantly, the real problem is power transformers.
A 60 hz xfmr run on 50 hz will have insufficient iron. With its
lower reactance, it will overheat at the lower freq, and often
*smoke*. However some equipment is designed to handle the lower
freq. (Example most HP stuff) And it is designed to handle 220
to boot.
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In article <2431@ncoast.UUCP> wb8foz@ncoast.UUCP (David Lesher) writes: > >A 60 hz xfmr run on 50 hz will have insufficient iron. With its >lower reactance, it will overheat at the lower freq, and often >*smoke*. I can't see that the reactance will change much, as 50Hz represents a 17% decrease from 60Hz, and since Xl = 2*pi*f*L, Xl changes linearly with f. Besides, all the transformers I've seen in both commercial and consumer gear meant for 60Hz service used transformers specified for 48Hz to 62Hz. Now, going to 400Hz power is another story... I think the real issues here are: 1) does any circuitry use the 60Hz as a timebase? 2) does the power supply have a way to be switched to 220V service? 3) if there's no switching for 220V, is the power supply one of the switching types that are designed for 80V to 240V? The answer to the original question is then: NOT[1] AND ([2] OR [3]) -- --==---==---==-- .. One, two! One, two! And through and through .. ARPA: cgs@umd5.UMD.EDU BITNET: cgs%umd5@umd2 UUCP: ..!seismo!umd5.umd.edu!cgs