David,
I remember when I was pretty young in school, say in the mid to late 70's, they
made a push about using the metric system. There was so many complaints from
partents, and even the teachers themselves that it didn't go anywhere. The
thing is, a lot of engineering formulas use the metric system. Take
transformers, the standard formula is all metric. It does have a converted
formula though where you can use gauss with square inches. That's where I made
the mistake earlier using 6.45. That is for converting square centimeters into
square inches. So it directly converts gauss per sq cm to lines per inch. When
I started using that years ago, I like to never got the hang of it, so I use a
formula which already has it in it so I dont leave it out by mistake.
Metric;
N = V x 10^8 / 4 x F x f x a x B x s
Inch;
N = V x 10^8 / 25.8 x F x f x a x B x s
Where 4 x 6.45 = 25.80
Or if your doing sine wave only, F = 1.11 so 25.8 turns to 28.638
The formula above is easy to change around by replacing N with f, a, or B and
putting N in their place.
N = Number of turns.
V = Voltage on the primary.
F = Form factor where 1 is for square waves, and 1.11 for sine waves.
f = Operating frequency.
B = Flux density in gauss.
s = Stacking factor.
You can see from above how one little screw up can throw it all off.
Best,
Will
*********** REPLY SEPARATOR ***********
On 8/5/05 at 2:38 PM David C. Hallam wrote:
>I don't think there was ever any mandatory requirement that the change be
>affected. Probably US industry and business made a informal or maybe in
>some cases a formal analysis and decided it just wasn't worth it.
>
>In my career as a metallurgical engineer, I have had to work with both
>systems and see no really compelling argument for the cgs system.
>
>David C. Hallam
>KC2JD
>
>-----Original Message-----
>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
>Behalf Of Peter Frenning [OZ1PIF]
>Sent: Friday, August 05, 2005 1:59 PM
>To: amps@contesting.com
>Subject: Re: [Amps] Metric system
>
>
>Just to stir the pot one more time...
>Didn't the US officially adopt the metric system by Congress resolution
>sometime in the 1980's?
>I distinctly remember the CA highway signs sporting Miles and Kms when I
>lived in San Jose in the late eighties, local radio and TV stations also
>gave temperatures in both Fahrenheit and Celcius. Visiting CA 10 years
>later
>on business trips, there no Metric signs anywhere to be seen!
>Apparently this is one example of inertia winning out over plain common
>sense - and law!
>
>Vy 73 de OZ1PIF, Peter
>
>********** OZ1PIF **************
>email: oz1pif(no-spam-filler)@privat.dk
>http://home24.inet.tele.dk/oz1pif/
>Ph. +45 4619 3239
>Snailmail:
>Peter Frenning
>Ternevej 23
>DK-4130 Viby Sj.
>Denmark
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>
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