Any EEs or EE Students - Need your help

[SaturnX]

Hey,

Alright, right now I'm trying to figure out the ampacity of a flat aluminum bar.

Ambient temp is 30C, and I've got the cross sectional area of the bar.

I need to calculate the ampacity of the bar (taking into account frequency (60Hz), skin effect, and any other real world factors).

The flat bar is being used as a bus bar within a Substation and I've been flipping through the Standard Handbook for Electrical Engineers but all that covers is ampacities of tubular Cu/Al bus bars.

Does anyone know how this could be done?

Thanks!

<-- Starting 3rd Year EE in about 3 weeks

--Mark

 

[acemcmac]

42.

I'm not an EE but I did stay at a Holiday Inn Express last night.

 

[esun]

I could help you with a circuits or devices problem. I've never even heard of ampacity, though.

 

[Hyperion042]

Can you just take the limit as inner radius drops to zero for the tubular case, or are these just numbers they're supplying?

 

[Canun]

The textbook should have the ampacity ratings of materials if you are in school. Been years since my EE courses, but it should be in there. If not, most electric manufacturers like Cutler Hammer should have the ratings of their items on their website.

 

[Analog]

They go thru an example of an aluminum bus bar here:

http://www.ibiblio.org/obp/electricCircuits/DC/DC_12.html

search for the example on the aluminum bar.

 

[RaynorWolfcastle]

Well I've never done this, but it looks messy. To get ampacity you usually need to figure out the max current that heats the conductor to some temperature (which you don't state). Since I know nothing about thermo-dynamics, I can't tell you how the heat will dissipate from the aluminum bar, and consequently I can't guess at how much power you can pump in there.

If you've got a maximum steady-state power dissipation given to you (or calculated through some other means). I am guessing you can calculate the ampacity using Maxwell's equations, since you want to take skinning effects into account (though there is probably an easier way to do this).

 

[SaturnX]

Originally posted by: Hyperion042
Can you just take the limit as inner radius drops to zero for the tubular case, or are these just numbers they're supplying?

The values I have for tubular bus bars are simply the ratings, nothing else. Yeah I figured that this would be an above average task... gonna still keep trying to figure it out, if anyone has any other insight that'd be great.

Thanks!

--Mark