Using tables for current calculation

[tlauridsen]

I am trying to make a template for my upcoming electrical examination. I am calculating the voltage drop in af transmission line and I would like to use either a matrice or a table to make it easy and eliminate the risk of faults.

I have added a screen print of how I am doing it right know. I would like the fourth row in my table to be the sum of the above currents, but in the opposite direction. Is that even possible?

Another thing I would like to know is if it is possible to use get the value for the area that I have marked with a circle?

If needed I will upload the file to.

[LucMeekes]

I'm afraid it's not possible in a simple way. Here's an experiment:

I left the last value in the  Ibc undefined, that's no problem. But within the Iab column (vector) the vector Iab is unknown.

Further notice that when all currents are defined (with units) adding a unit in the table results in multiplication of the units.  (we get A squared!).

But this works:

I don't see the circle you talk about...

Luc

[tlauridsen]

Thank you for the help. I appreciate it very much.

Think I forgot to save it after I made the circle

I had put a circle around the value in coloumn two, row two, and would like to know if I in someway be a command can use that value?

It is a shame that excel does not use complex numbers. I guess that would have made it easier

[LucMeekes · Accepted solution]

You mean the value I20C+I20F in the column for IBC?

...

You have to realize that:

- Excel is a completely different beast than Mathcad or Prime.

- a Table in Prime is nothing more (and nothing less) than a collection of (column) vectors, and as far as I can see it's most (or...only) useful for Input values.

The name of each column vector and the unit of the values (if any) in it, are shown above the bar, the elements of the vector (the values themselves) are listed below the bar. As said, and shown above in my first answer, each vector element is multiplied with the unit you place above the bar, even if it already has a unit... {I suggest you take the A unit from the table}.

You can use the vectors in subsequent calculations just by addressing them by their name, as I've done in my previous post.

So, back to second column, second row:

You can simply use it by calling it by its proper name: IBC[1

Where: BC must be subscript, because you defined IBC that way.

[ brings you to the index, which points to the element of your choice in the vector IBC.

1 is the index of the vector element, assuming that you did NOT set ORIGIN to another than its default value which is 0.

If you did change ORIGIN (probably to 1) then you'd have to use IBC[2.

Hope this is clear.

Success! (Also with you examination.)

Luc

[nas0k]

I don't think you can do it that way. You have defined each table column which includes the summation; you are asking MC to sum each column. Possibly re-define; index the rows in your summation may work.

I hope this helps.

[LucMeekes]

"Possibly re-define; index the rows in your summation may work."

I've tried that, see above, it doesn't work because the vector isn't known inside the vector, so you cannot use it to index into.

Essentially you would be trying:

which fails.

Luc

[nas0k]

Thanks Luc, for the clarification.

The symbolic solution is curious. I copied and pasted the initial symbolic, which resulted in: