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Home > Archive > Electrical Engineering > February 2008 > Log-Log Graph Paper For Time Current Curves
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Log-Log Graph Paper For Time Current Curves
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| JuanDiegoDeLasNalgas@gmail.com 2008-02-06, 1:25 pm |
| Can anyone tell me if a standard exists for the length per decade of
log-log graph paper used in time current curve (TCC) plots?
Since these were designed for tracing, the scales of every
manufacturers paper had to be the same. I've measured various
originals and copies, and the distance appears to be about 2.21 inches
per decade. However there is bit of variation between 2.20 to 2.23,
the distance for vertical decades of time in seconds also seem to be a
bit shorter than the horizontal distance for current in amperes.
It would be nice to know is there is some old ANSI standard or
something that spells out how this paper is to be made.
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| Bill Shymanski 2008-02-06, 9:25 pm |
| JuanDiegoDeLasNalgas@gmail.com wrote:
> Can anyone tell me if a standard exists for the length per decade of
> log-log graph paper used in time current curve (TCC) plots?
>
> Since these were designed for tracing, the scales of every
> manufacturers paper had to be the same. I've measured various
> originals and copies, and the distance appears to be about 2.21 inches
> per decade. However there is bit of variation between 2.20 to 2.23,
> the distance for vertical decades of time in seconds also seem to be a
> bit shorter than the horizontal distance for current in amperes.
>
> It would be nice to know is there is some old ANSI standard or
> something that spells out how this paper is to be made.
A couple of years ago I was looking around the consulting engineering
office where I work and I couldn't find any proper time/current curve
paper. Seems we've modernized and are now using computer programs for
everything...after a fair bit of tedious work I leaned the program well
enough to get the results I'd have gotten in 20 minutes with the
time-current paper. Ahh, progress.
Bill
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| John Rye 2008-02-07, 9:25 am |
| Hello All
In article
<30f328aa-bad7-43b2-bbdf-8c9116cb6c65@h11g2000prf.googlegroups.com>,
<JuanDiegoDeLasNalgas@gmail.com> wrote:
> Can anyone tell me if a standard exists for the length per decade of
> log-log graph paper used in time current curve (TCC) plots?
> Since these were designed for tracing, the scales of every
> manufacturers paper had to be the same. I've measured various
> originals and copies, and the distance appears to be about 2.21 inches
> per decade. However there is bit of variation between 2.20 to 2.23,
> the distance for vertical decades of time in seconds also seem to be a
> bit shorter than the horizontal distance for current in amperes.
> It would be nice to know is there is some old ANSI standard or
> something that spells out how this paper is to be made.
In the UK the practice was to use the manufacturers curves to make templates
which were then used on pads of graph paper. The usual manufacturer for the
graph paper was a company called Chartwell. Although I am now retired I still
have some of their paper in my archives. The 3 decade by 2 decade paper was
based on 3" per decade. In the old UK manufacturers pamphlets the scales
vary, so thescaling was not standardised amongst the manufacturers in the UK.
John
--
John Rye
Hadleigh IPSWICH England
<http://web.ukonline.co.uk/jrye/index.html>
---< On Line using an Acorn StrongArm RiscPC >---
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<JuanDiegoDeLasNalgas@gmail.com> wrote in message
news:30f328aa-bad7-43b2-bbdf-8c9116cb6c65@h11g2000prf.googlegroups.com...
> Can anyone tell me if a standard exists for the length per decade of
> log-log graph paper used in time current curve (TCC) plots?
>
> Since these were designed for tracing, the scales of every
> manufacturers paper had to be the same. I've measured various
> originals and copies, and the distance appears to be about 2.21 inches
> per decade. However there is bit of variation between 2.20 to 2.23,
> the distance for vertical decades of time in seconds also seem to be a
> bit shorter than the horizontal distance for current in amperes.
>
> It would be nice to know is there is some old ANSI standard or
> something that spells out how this paper is to be made.
Variation -0.01 to +0.02 inch make that much of a difference? Coordination
is an art not exact science - take an average, shift the paper and fudge a
little. Anyway I never notice paper differences when laying out over a light
table but was well over 10 years ago and couldn't tell you where my log-log
papers are.
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| Don Kelly 2008-02-08, 9:25 pm |
| ----------------------------
" Frank" <noreplay@nothome.net> wrote in message
news:6tSdnVgH4az-jzDanZ2dnUVZ_tWtnZ2d@comcast.com...
>
> <JuanDiegoDeLasNalgas@gmail.com> wrote in message
> news:30f328aa-bad7-43b2-bbdf-8c9116cb6c65@h11g2000prf.googlegroups.com...
>
>
> Variation -0.01 to +0.02 inch make that much of a difference? Coordination
> is an art not exact science - take an average, shift the paper and fudge a
> little. Anyway I never notice paper differences when laying out over a
> light table but was well over 10 years ago and couldn't tell you where my
> log-log papers are.
---------
To add to your comments, since when can one use log-log graph paper with 2+
inches per decade with an expected accuracy of 1% or less? The variations
in the paper are smaller than the variations in "reading" the graph.
Ambient temperature will throw more uncertainty into the results than paper
variations.
This seems to be in the same category as " my calculator can give the
answer (obviously always correct as it magically adjusts incorrect button
pushing)to 10 figure accuracy even if the input data is known to 2
significant figures" --
Don Kelly dhky@shawcross.ca
remove the X to answer
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