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- To: owner-atm@shore.net
- Subject: BOUNCE atm@shore.net: Non-member submission from [Kurt Hillig <khillig@Chem.LSA.umich.edu>]
- From: owner-atm@shore.net
- Date: Fri, 11 Oct 1996 08:47:58 -0400 (EDT)
>From atm-owner Fri Oct 11 08:42:32 1996 Received: from Chem.LSA.umich.edu (U.Chem.LSA.UMich.Edu [141.211.68.92]) by relay1.shore.net (8.7.5/8.7.3) with SMTP id IAA08908 for <atm@shore.net>; Fri, 11 Oct 1996 08:42:31 -0400 (EDT) Received: from Be.Chem.LSA.UMich.Edu by Chem.LSA.umich.edu (951211.SGI.8.6.12.PATCH1042/1123-1.0(Chem)) id IAA18793; Fri, 11 Oct 1996 08:42:28 -0400 Date: Fri, 11 Oct 1996 08:42:29 -0400 (EDT) From: Kurt Hillig <khillig@Chem.LSA.umich.edu> Reply-To: Kurt Hillig <khillig@umich.edu> To: "David W. Stokes" <dstokes@texas.net> cc: atm@shore.net Subject: Re: ATM Suggest motor for barndoor mount? In-Reply-To: <325D9A93.339E@texas.net> Message-ID: <Pine.ULT.3.95.961011083456.6649B-100000@Be.Chem.LSA.UMich.Edu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Thu, 10 Oct 1996, David W. Stokes wrote: > I would appreciate your suggestions on motor selection for a barndoor > camera mount. Must be cheap and durable, DC. Are geared or step motors > better for this application? I have not used step motors before. If it must run on DC power, stepping motors are much easier to run at a constant and adjustable speed - they're basically driven by an oscillator, which can be crystal-controlled and with a variable frequency divider stage to set the frequency quite accurately. Ordinary DC motors, unless they're run with some sort of feedback controller (tachometer), don't hold a constant speed if the input voltage varies (e.g. as your battery drains). Of course, you could put a voltage regulator ahead of the motor, but make sure it can handle the current that the motor draws, and make sure you add some capacitors and diodes to protect the regulator from commutation spikes.... Dr. Kurt Hillig Dept. of Chemistry I always tell the fax (313)647-4865 University of Michigan absolute truth phone (313)647-2867 Ann Arbor, MI 48109-1055 as I see it. X.500 khillig@umich.edu Computers were invented to help people waste more time faster.
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