Trying to calculate skin effect ratio for rectangular section.

[dbecker]

Hello,

I am trying to compute the skin effect ratio of a rectangular section that is 44mm tall and 25.4mm wide with a known length of 251.4mm.

The AC current is defined as being 133 Hz at 1350 Amps through this conductor.

I am using this formula from this website.

http://www.copperinfo.co.uk/busbars/pub22-copper-for-busbars/sec4.htm

The table is near the bottom of the page and is used for rectangular section.

The formula calls for me to calculate the x-axis:

SQRT(frequency / R_0(for 1000m))

When I calculate the above value I get about 2800. This seems wrong as the X-axis does not extend that far and I do not believe I should have to extrapolate out that far.

The way I understand it, R_0(1000) = resistance for 1000m

frequency = Hz

When I do the calculation I use SQRT(133Hz / 1.68x10-5) = 2800

What am I doing wrong? My X-axis should be somewhere between 0 and 100. 2800 is way too high?

Please advise,

Thanks!

 

[dbecker]

I just answered my own question.

I forgot to divide Resistivity x length by area.

My new answer is 44, much more reasonable!!