REFLECTOR:Buss material

Mon, 26 Apr 2004 13:31:19 -0700

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on 4/25/04 10:23 AM, Al Gietzen at ALVentures@cox.net wrote:

Aluminum is at least a good conductor; resistance about 1.6 times that =
of
copper.  Brass, on the other hand, has resistance about 4 times that of
copper.  The 1/8=B2 x =BD=B2 copper I had I got from Aeroelectric; I was =
surprised
to find that he is now selling .025 thick brass instead.  In a =BD=B2 =
width,
that=B9s equivalent to about a #15 wire.  Seems pretty marginal for a =
buss
with half dozen or more circuits running off.=20

I had the same concern about the thickness of my bus bar.  Bob Nuckols =
told
me that, in a DC circuit, it's the surface area, not the cross section, =
of
the conductor that determines the current carrying capacity.  I can't
remember the thickness of mine but it seemed thin at the time.

Dave Scharfenberg=20

=20

I=92ll have to take issue with Bob on this one =96 if that=92s what he =
meant.
It=92s the cross-sectional area (and length) that determines resistance.
Resistance, in turn determines voltage loss  (I*R), and the heat =
generated
I2*R.  The surface area will influence heat transferred to the air.  =
I=92d say
if the buss is running more than a few degrees above ambient it is =
probably
too small, because there isn=92t much reason to be incurring voltage =
loss at
the point of distribution.

=20

If I recall correctly, surface effects on resistance come into play only =
for
high frequency and/or high voltage applications =96 not an area in which =
I
have any expertise.

=20

Al

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on 4/25/04 10:23 AM, Al Gietzen =
at ALVentures@cox.net wrote: 
 
Aluminum is at least a =
good
conductor; resistance about 1.6 times that of copper. &nbsp;Brass, on =
the other
hand, has resistance about 4 times that of copper.&nbsp; The 1/8=B2 x =
=BD=B2 copper I
had I got from Aeroelectric; I was surprised to find that he is now =
selling .025
thick brass instead.&nbsp; In a =BD=B2 width, that=B9s equivalent to =
about a #15
wire.&nbsp; Seems pretty marginal for a buss with half dozen or more =
circuits
running off.&nbsp; 
 
 
I had the same concern about the thickness of my bus bar. &nbsp;Bob =
Nuckols
told me that, in a DC circuit, it's the surface area, not the cross =
section, of
the conductor that determines the current carrying capacity. &nbsp;I =
can't
remember the thickness of mine but it seemed thin at the time. 
 
Dave Scharfenberg

<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>&nbsp;</span></font></p>

I&#8217;ll have to take issue =
with Bob
on this one &#8211; if that&#8217;s what he meant.=A0 It&#8217;s the
cross-sectional area (and length) that determines resistance. =
=A0Resistance, in
turn determines voltage loss=A0 (I*R), and the heat generated =
I2*R.=A0
The surface area will influence heat transferred to the air.=A0 =
I&#8217;d say if
the buss is running more than a few degrees above ambient it is probably =
too
small, because there isn&#8217;t much reason to be incurring voltage =
loss at the
point of distribution.

<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>If I recall correctly, surface =
effects
on resistance come into play only for high frequency and/or high voltage
applications &#8211; not an area in which I have any =
expertise.</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>Al</span></font></p>

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