Star and delta connected circuits

WBahn

Joined Mar 31, 2012
30,233
You need to show your best effort to get as far as you can on your homework. We can then help you identify mistakes you might have made and help you get past your current stumbling block.
 

MrAl

Joined Jun 17, 2014
11,559
I am struggling with this question can anyone help?
Hello there,

If you really want help you should present your drawings in a neater form. That drawing was very hard to read because of the raster lines.
Here is a clearer version of that drawing so other members can view it better.
Also note how much lower the byte count is on this new image. You can often get by with a much lower jpeg quality setting because the drawings are usually large enough.
 

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frankiem

Joined May 13, 2022
12
Hello there,

If you really want help you should present your drawings in a neater form. That drawing was very hard to read because of the raster lines.
Here is a clearer version of that drawing so other members can view it better.
Also note how much lower the byte count is on this new image. You can often get by with a much lower jpeg quality setting because the drawings are usually large enough.
Thank you
 

MrAl

Joined Jun 17, 2014
11,559
Thank you
I made a new drawing that is more readable. It looks like you got I1 right if you consider rounding errors. I got a slightly lower value for I1 current but the same phase angle. The value I got was very roughly 0.1 amps lower than yours. You might check that or just let it go as a rounding difference. I use 16 digits for most calculations straight through to the end.
Since I1 looks right, and the phase angle looks right, it looks like I2 and I3 are right also because all phases would have the same current in a balanced system, and since the phase of I1 is right also, it looks like the other two phases are right also because all we have to do to check is add 120 degrees and 240 degrees to the phase of I1 to get the other phase angles.
I did not check the line currents yet though.

[LATER]
Ok the line currents look ok if we ignore the rounding errors again, which for the line currents are about 0.2 amps for each phase. That's only an error of about 0.2 percent which may or may not be significant depending on the goals of this exercise. More directly notable though is the line current amplitudes you posted are not exactly the same. Since this is a balanced system, they should be exactly the same. You may want to look into that.

Here is the new drawing and it is slightly easier to read, but you should really learn to print more neatly so it's easy for others to read. You want it to be easy to read so other members don't mind going over it and possibly helping you with it.
 

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