Xref: utzoo rec.travel:18631 rec.radio.amateur.misc:1059 sci.electronics:18880 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!decwrl!adobe!burgund!burgett From: burgett@burgund.adobe.com (Michael Burgett) Newsgroups: rec.travel,rec.radio.amateur.misc,sci.electronics Subject: Re: large 110->220 transformers Message-ID: Date: 29 Mar 91 00:04:13 GMT References: <1991Mar28.190723.9681@athena.cs.uga.edu> <1991Mar28.211132.3521@bellcore.bellcore.com> Sender: news@adobe.COM Followup-To: rec.travel Organization: Adobe Systems Incorporated, Mountain View Lines: 20 In-reply-to: karn@epic.bellcore.com's message of 28 Mar 91 21:11:32 GMT In article <1991Mar28.211132.3521@bellcore.bellcore.com> karn@epic.bellcore.com (Phil R. Karn) writes: [... much good and useful info deleted for brevity....] Alarm clocks or other devices with synchronous motors (e.g., turntables and analog tape decks) will NOT operate properly off European power even with a transformer, as their motor speeds are determined by the power frequency. (This may not be true for ALL alarm clocks, turntables and tape decks as some may have internal crystal clock references, but without knowing the design you can't be sure.) Note that CD players are not a problem here as their internals are always driven from a crystal reference, not the AC power line. The key here, is if it has a motor, ac motors will run slow, dc motors will run fine. A crystal reference isn't always necessary. Digital clocks (which don't even have a motor) will often run slow, but if you have a spec sheet on the clock chip used, it's usually simple a matter of adding or lifting ground from a particular pin to change between 50 and 60 Hz. Good post.... mike burgett burgett@adobe.com