Does anyone know how to calculate temperature rise above ambient in a
cable which is dissipating power due to voltage drop and current flow?

For example, a 12 ft length of #4 cable carrying 100 amps dissipates
about 35 watts total, approximately 3 watts per foot. That causes a
certain amount of heating. Assuming free space and decent air flow,
how warm is the cable likely to get at 100 degrees F ambient
temperature?

Are there any good web sites for that calculation?

Thanks in advance.

Wayne B :

For example, a 12 ft length of #4 cable carrying 100 amps dissipates
about 35 watts total, approximately 3 watts per foot. That causes a
certain amount of heating. Assuming free space and decent air flow,
how warm is the cable likely to get at 100 degrees F ambient
temperature?

You might start by reading

http://en.wikipedia.org/wiki/Heat_transfer_coefficient

, but they don't give usable coefficient values.

On Wed, 22 Jun 2011 13:33:09 -0400, Wayne B
wrote:

Does anyone know how to calculate temperature rise above ambient in a
cable which is dissipating power due to voltage drop and current flow?

For example, a 12 ft length of #4 cable carrying 100 amps dissipates
about 35 watts total, approximately 3 watts per foot. That causes a
certain amount of heating. Assuming free space and decent air flow,
how warm is the cable likely to get at 100 degrees F ambient
temperature?

Are there any good web sites for that calculation?

Thanks in advance.

Try:
http://www.standard-wire.com/current...ty_copper.html
http://donsnotes.com/home_garden/wire.html
http://www.delcowireus.com/current-c...g-capacity.php

I think that your calculations are off. A quick look shows a
resistance for #1 cable at 0.12 ohms/1,000 ft. or .00012 ohms/ft. so a
12 ft. length of #1 has a resistance of .00144 ohms. Voltage through
the cable is: V = IR or V = 12 x .00144 = 0.144 volts. Power absorbed
by the cable is then P = V x A = 0.144 x 100 = 14 watts.

Cheers,

Bruce

On Thu, 23 Jun 2011 08:39:24 +0700, Bruce
wrote:

On Wed, 22 Jun 2011 13:33:09 -0400, Wayne B
wrote:

Does anyone know how to calculate temperature rise above ambient in a
cable which is dissipating power due to voltage drop and current flow?

For example, a 12 ft length of #4 cable carrying 100 amps dissipates
about 35 watts total, approximately 3 watts per foot. That causes a
certain amount of heating. Assuming free space and decent air flow,
how warm is the cable likely to get at 100 degrees F ambient
temperature?

Are there any good web sites for that calculation?

Thanks in advance.

Try:
http://www.standard-wire.com/current...ty_copper.html
http://donsnotes.com/home_garden/wire.html
http://www.delcowireus.com/current-c...g-capacity.php

I think that your calculations are off. A quick look shows a
resistance for #1 cable at 0.12 ohms/1,000 ft. or .00012 ohms/ft. so a
12 ft. length of #1 has a resistance of .00144 ohms. Voltage through
the cable is: V = IR or V = 12 x .00144 = 0.144 volts. Power absorbed
by the cable is then P = V x A = 0.144 x 100 = 14 watts.


===

Bruce, lots of good information there, thanks. My calculations don't
add up to yours because of an allowance for connector resistance in
addition to the cable.

It looks like the maximum current should not exceed 140 amps in order
to keep the temperature below 110 C. That's within my expected
charging limit so should be OK with #4 cable but I'll have to keep an
eye on it for a while.

On Thu, 23 Jun 2011 08:39:24 +0700, Bruce
wrote:

On Wed, 22 Jun 2011 13:33:09 -0400, Wayne B
wrote:

Does anyone know how to calculate temperature rise above ambient in a
cable which is dissipating power due to voltage drop and current flow?

For example, a 12 ft length of #4 cable carrying 100 amps dissipates
about 35 watts total, approximately 3 watts per foot. That causes a
certain amount of heating. Assuming free space and decent air flow,
how warm is the cable likely to get at 100 degrees F ambient
temperature?

Are there any good web sites for that calculation?

Thanks in advance.

Try:
http://www.standard-wire.com/current...ty_copper.html
http://donsnotes.com/home_garden/wire.html
http://www.delcowireus.com/current-c...g-capacity.php

I think that your calculations are off. A quick look shows a
resistance for #1 cable at 0.12 ohms/1,000 ft. or .00012 ohms/ft. so a
12 ft. length of #1 has a resistance of .00144 ohms. Voltage through
the cable is: V = IR or V = 12 x .00144 = 0.144 volts. Power absorbed
by the cable is then P = V x A = 0.144 x 100 = 14 watts.

Cheers,

Bruce


Correction. I should have written "voltage loss through the cable"
rather then "voltage through the cable"..

Cheers,

Bruce

Search locomotive optimization (SEO) is the handle of improving the visibility of a website or a spider's web recto in search engines via the "unembellished" or un-paid ("integral" or "algorithmic") search results. In inexact, the earlier (or higher ranked on the search results send for), and more time again a plot appears in the search results laundry list, the more visitors it will inherit from the search motor's users. SEO may butt divergent kinds of search, including twin search, state search, video search, hypothetical search,[1] news search and industry-specific vertical search engines.

As an Internet marketing scenario, SEO considers how search engines function, what people search fitting for, the actual search terms typed into search engines and which search engines are preferred nearby their targeted audience. Optimizing a website may require editing its content and HTML and associated coding to both increase its applicableness to determined keywords and to remove barriers to the indexing activities of search engines. Promoting a site to proliferate the thousand of backlinks, or inbound links, is another SEO tactic.

The acronym "SEOs" can refer to "search engine optimizers," a period of time adopted by way of an activity of consultants who uphold at fault optimization projects on behalf of clients, and via employees who present SEO services in-house. Search engine optimizers may tender SEO as a stand-alone putting into play or as a part of a broader marketing campaign. Because remarkable SEO may require changes to the HTML author cypher of a site and placement contentedness, SEO tactics may be incorporated into website increment and design. The clauses "search machine familiar" may be tempered to to describe website designs, menus, delight management systems, images, videos, shopping carts, and other elements that contain been optimized in place of the long of search machine exposure.

a href=http://giaosuseo.com/seo-la-gi/seo/a