Temperature Rise within a Switchboard: How to Derive a Formula?

<how can I derive a formula for TR at busbar >

Probably the only predictable heating is on heavy-current Busbars.**

Hardly any at Breaker Teminals.

So take that** and create mathematical model of Temp Rise in the closed Panel/Box with/without ventilation.

What will you do with that?

Iwould have a simple Busbar/panel Body Temp. alarm rigged up instead.

this is required for predicting temprature rise before actual testing sot hat we can avoid no of tests required.

WOuldn't IR² do the trick? What is the resistance of the conductors, and how much current will they carry? Then you can estimate expected watts of heating.

Or am I too simple minded?

Ok,

1: add all the I²R

2: measure the surface area

3: measure the ambient air temp and the temp of large bodies it is attached to

4: segregate the surfaces (air vs bodies)

5: look up thermal resistance of box material

6: multiply area,watts,Θ_box

Look at semiconductor datasheets for examples of calculating temp rise as a function of watts dissipated.

Of course, the question is temp rise not heat gain! (dohh). Sorry for my incomplete answer.

There is no ready made formula for deriving the temperature rise of the switch board.

But you have to calculate the heat generated by the components inside the board,take the ambient temerature and calculate the probable temperature rise at various locations inside the switch board.

one has to calculate.I have done this exercise for my switch boards.May be if you could furnish data we can try to help,but against professional fee.

I assume the switchboard is within an enclosure. This may help...

http://www.hoffmanonline.com/product_catalog/tech_resources.aspx?cat_1=34&cat_2=137&amp;SelectCatID=137&CatId=137

Look in the thermal management section...

.

Thank you

I SEEN ALL THE INFORMATION BUT I NEED EXACT GRAPH BETWEEN WATT PER FEET VS TEMP RISE BECAUSE NOBODY WILL ACCEPT THIS

SANJAY J.

Sanjay,

In general, Heat in - Heat out = Temp rise*(Specific heat_n * mass_n)

To derive a formula, you need the specific heat of all the materials and their respective masses.

With this method you don't really need the heat out, just the heat in, which is I²R and then do the mass and specific heat measurements/calculations. You will have to include the volume of air in the enclosure; any exchanged air further complicates matters, but can be tracked too.

Your error will by entropy beyond thermal and that should be negligible.

Hope this helps.

Thanks for the replay,kindly send your contact details so that we can address our reqirment.

REGARDS

Murali