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- Newsgroups: sci.electronics
- Path: sparky!uunet!mnemosyne.cs.du.edu!nyx!aduell
- From: aduell@nyx.cs.du.edu (Tony Duell)
- Subject: Re: Can 220V 50 Hz Stuff be run on US 220V 60 HZ power ?
- Message-ID: <1992Sep1.201938.8326@mnemosyne.cs.du.edu>
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- References: <JCHAPMAN.92Aug30025555@polaris.cv.nrao.edu> <1992Aug30.18374
- Distribution: sci
- Date: Tue, 1 Sep 92 20:19:38 GMT
- Lines: 43
-
-
- Don't blame me if you fry something, because I've never gone this way,
- although I have run lots of american equipment in England.
- 1) The frequency difference, 50Hz/60Hz. Basically, switch-mode PSU's don't
- mind at all, the first thing they do is rectify the mains to DC anyway.
- Switch mode PSU's will run off 50 Hz, 60Hz, DC, square waves, you name
- it!. Transformers are more of a problem. Normally, 50Hz equipment will
- work off a 60Hz supply with no problems, and I've never had any problems
- with 60Hz stuff on a 50Hz supply. The transformer runns hottter in the
- latter case, but not significatly. Waatch out for things that are tied to
- the frequency though. Some older record turntalbes/tape recorders/LARGE
- (14 " demountable) hard disks/clocks/timers use the mains frequency as a
- reference. In that case you will have to get a modification kit from the
- manufacturer.
- 2) Voltage. 110 V stuff on a 220V supply either needs a new transformer, A
- tap change, or a step down autotransformer. I've done all 3. The other way
- is easier. First find out if there is a intenral adjustment for 110 V
- mains. If not, check if there is a american model (or similar - going the
- other way I fitted a British CoCo2 transformer in a Tandy CoCO3 that I was
- going to use over here). If there is, buy the transformer, and fit it.
- Othewise you can use a 220V socket in America. The problem is that neither
- side is grounded, whereas one side of the 110V supply and of our 240V
- supply is. This shouldn't matter really - the design should never
- intentionally pass current from either side to the ground conductor. You
- should use a Double-pole switch in this case though (in fact, you should
- use one anyway!). Most suff should work OK at 220V neither side grounded.
- Anohter nice trick. You can (If you have the schematics, and know what you
- are doing, modify the input side of a 240V switch-mode PSU from a bridge
- rectifier (giving about 340V on the smoothing cap) to a voltage doubler.
- In fact the switches on most small switch-mode PSUs do just that. If there
- is no switch, you can try anyway (By wswitch, I of course mean a voltage
- selector switch, not an on-off one).
- 3) Video standards. HELP!!!!! RGB is possible (most monitors work at
- either frequency, and of couse IBM PC type monitros work at 60HZz vertical
- everywhere (except for those high-end standrds that use 70Hz etc). No
- problems at all. TV/composite is more of a problem. very little modern
- equipment uses the mains for any timing reference in the video stuff, so a
- european video recorder will play into a european TV no matter what the
- mains frequency is. Just don't expect to be able to record off-air
-
- -tony 'PDP11 Hacker' Duell
- ard@siva.bris.ac.uk
-
-