Kirchoff - solve block Prime

[tlauridsen]

In MathCad 14 it was no problem using solve combined with Kirchoff laws on a circuit to figure out different current, but in MathCad Prime it doesn't work when i type the same things in solve block.

What am I doing wrong?

MathCad 14 on the left and Prime on the right

[MikeArmstrong]

Firstly can you provide a worksheet as it is difficult to determine the issue from an image.

However, it seems you are solving symbolically in Mathcad and not in Prime. Is there a reason you are solving symbolically?

Mike

[tlauridsen]

I have just used the method that i have been tought one my Nspire.

[RichardJ]

In MC 15 (left panel) you are using a symbolic solve, which does not require guesses for the variables you wish to solve for. In Prime (right panel) you are using a numeric solve, which does require guesses. Either use a symbolic solve, or add guess values for the currents.

You should also get rid of the first equation. Given I1 and I2 it's trivial to calculate I after the solve block.

Lastly, Prime includes a converter that will convert MC 15 worksheets to Prime worksheets. That saves you the work of retyping everything, and also avoids the possible errors associated with doing that.

[ValeryOchkov · Accepted solution]

See please pictures 17/15-17.18 and one Mathcad Prime sheet here - Study 17. Cogeneration (CHP), trigeneration (CCHP) and quadrogeneration (CCHPI) or  how  much  of  mathematic is contained in thermal engineering

[ValeryOchkov]

Thanks for the correct answer!

The book Elrctrical Engineering studies with Excel, Mathcad and Internet is in costraction!

[tlauridsen]

Arh know I can see it... Those guess values are totally misunderstood by me. It works know. But I can't see the idea of theses guess values?  Can anyone explain it to med?

[MikeArmstrong]

I suggest you read up on Solve Blocks in the help menu.

Mike

[RichardJ]

All numeric non-linear solvers are iterative. They start at some point on the error surface, and head downhill until they find a minimum (i.e. a minimum error). The starting point is given by the guess values.