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Article #1970Re: Tachometers
From: Iskandar Taib
Date: Mon, 25 Jan 1993 04:43
Date: Mon, 25 Jan 1993 04:43
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In article <727805456snz@harrier.demon.co.uk> bob@harrier.demon.co.uk writes: > >>Actually, regarding calibrating to an electric light wouldn't that be >>1800 rpm for a two blade prop or 1200 for a three blader? >> >>Also, you would need a fluorescent light or some other light that >>flickers more than an incandescent light. >> >>Just a thought... > >>Wrrooonnngggggggg... An incandescant lamp running on 50 Hz mains actually >flashes 100 times/sec. The sine-wave goes both posative and negative peaks >in ecah cycle, ie 100 flashes/sec. Multilpy by 60, gives 6000 flashes per >minute.. So on the two blade setting it should read 300 ( 3000rpm ) and on >three blade 200... > >I guess your side of the pond where you run at 60Hz it would read 360 and 240. > >I'm not an expert on flourescant lights, (or much else really) :-) but they >run via some really high voltage gizmo which makes the gas in the tube >flouresce constantly.... Hmmm I think this is backwards. The filament of an incandescent lamp doesn't have enough time to cool down enough between cycles, so it should glow steadily. A fluorescent lamp, however, relies on the flow of electrons through a mercury vapor through the tube, and this can respond faster to the cycles of AC. Whether they flash 60x per second or 120x per second I don't know. -- ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@SILVER.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS !
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Newsgroups: rec.models.rc Path: arc1-ca.pugleaf.net!sparky!uunet!usc!sdd.hp.com!ux1.cso.uiuc.edu!usenet.ucs.indiana.edu!silver.ucs.indiana.edu!ntaib From: ntaib@silver.ucs.indiana.edu (Iskandar Taib) Subject: Re: Tachometers Message-ID: <C1E7t9.G82@usenet.ucs.indiana.edu> Sender: news@usenet.ucs.indiana.edu (USENET News System) Nntp-Posting-Host: silver.ucs.indiana.edu Organization: Indiana University References: <sfM8dMa00YUoAp54U6@andrew.cmu.edu> <727805456snz@harrier.demon.co.uk> Date: Mon, 25 Jan 1993 04:43:57 GMT Lines: 39