Steinmetz coefficient calculation

[Marius_P]

Hello,

I tried to calculate the Steinmetz coefficients as it was shown in another thread "Curve fitting", and I would like to know how to do a log-log plotting of the power density vs magnetic flux density.

I would like to see how accurate is the formula from my calculations and how well I can match with the graph from the datasheet.

Thank you!

[Werner_E]

Click on the expression for the x-axis (B) and chose "Logarithmic scaling" in the "Plot" Ribbon.

The n do the same for the expression for the y-axis (P(100,B)

[Marius_P]

Hello Werner,

Thank you very much for your reply.

I would like also to know how did succeed to represent on the same plot the line graph of P(100,B) and also the other graphical points in order to see how accurate is your Steinmetz equation?

Thank you!

[Cornel]

Like this?

[Marius_P]

Yes Cornel.

I tried to add traces on x and y axes but I got errors.

[Cornel]

Strange, because that's what I did. I added traces on x axis (B100_25deg and B100_100deg) and on y axis (P100_25deg and P100_100deg).

[Cornel]

How did you derived data from excel file?

[Marius_P]

Hello Cornel,

I use PTC v7, could you convert it please to 7th version?

[Cornel]

I have only 9th version at this moment. Maybe others can help with this.

[Marius_P]

Could you take a look please in my file in order to help me to understand why I am not able to add extra traces on the plot?

[Cornel]

[Marius_P]

This is what I got.

I am wondering, why I can't see all the points also on the first graph? 

[Cornel]

Adjust the minimum and maximum values for x and y axis (like 0 to 1000 for x axis, and 0 to 1000 for y axis)

[Werner_E]

You had paired the x- and y-expression not correct. You must either change the order of the expressions on the x-axis or the one of the expressions on the y-axis

[Marius_P]

Hello Werner,

The order seems to be correct, please look in the last screenshot that I placed, but it is not showing the complete graphical line and all the dots.

[Werner_E]

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The order seems to be correct,

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Now it is, yes.

You are using Prime's QuickPlot feature (plotting without explicitly defining the variable on the x.axis). If you do so, then Prime chooses a range from 0.04 up to 10 for the abscissa values (in your case for B).

Solution: Either define a range for B in front of the plot or manually edit the axis values as Cornel had suggested.
Prime allows to change the first, second and last value on each axis.

or use

or something like

For the second plot no line, only dots were chosen so the dots really represent the data points.

[Marius_P]

Hello Werner,

Thank you very much.

It seems that the graph looks better now.

[Marius_P]

From what I can see the values calculated using the determined Steinmetz coefficients are lower by some 10 times lower compared to the values from the excel file, extracted from the graph. This can be seen from the x&y axes coordinates.

Could you tell me please how to fix this?  

[Werner_E]

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@Marius_P wrote:

From what I can see the values calculated using the determined Steinmetz coefficients are lower by some 10 times lower compared to the values from the excel file, extracted from the graph. This can be seen from the x&y axes coordinates.

Could you tell me please how to fix this?  

---

As explained above this is because you let Prime choose the range of values used for B in the plot.

Solution is to either define a range for B yourself or manually edit the last and second value for the x-axis values.

[Marius_P · Accepted solution]

Hello Werner,

Thank you. It works now.