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Coil Current not matching Integrated Current
Posted Sep 17, 2013, 1:24 p.m. EDT Low-Frequency Electromagnetics Version 4.3b 1 Reply
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So I'm doing a 2d axial model. I'm using a multi-turn coil and I am plotting the current in the coil. I've defined my voltage as a step function and that is the excitation.
Just noticed that when I plot a point graph (1d) and select mf.ICoil_1 I get one plot with a max at about .16 amps.
When I graph by doing a surface integration of mf.Jphi (selecting the domain of the coil ) I get a max at about 16 amps. Now these graphs have the same exact shape, just have amplitude scaling.
There is a difference in a factor of 100. Now there are 100 turns in my coil... but aren't these two graphs representing the same thing? Or does mf.ICoil_1 just calculate the current through each individual wire where as integration calculated the total current?
Thanks in advance for any input!
1 Reply Last Post Sep 21, 2013, 6:20 a.m. EDT
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Posted:
1 decade ago
Hi Andy,
the multi-turn coil domain is a simple model and only takes the resistance of the wire into account (no proximity and no skin-effects). To get a correct result (considering the resistance), you have to specify the cross section area a_coil of one single wire.
Because the model spreads the coil-threads evenly over the selected surface, the current flowing through the surface is the Number of turns multiplied by the current of one thread (= ampere turns). Thats exactly what you noticed.
If you like to look at the single threads of the coil, you have to use the single turn coil model (there is a check box to activate for multi-turn) or the RLC-coil model.
Regards Ueli
the multi-turn coil domain is a simple model and only takes the resistance of the wire into account (no proximity and no skin-effects). To get a correct result (considering the resistance), you have to specify the cross section area a_coil of one single wire.
Because the model spreads the coil-threads evenly over the selected surface, the current flowing through the surface is the Number of turns multiplied by the current of one thread (= ampere turns). Thats exactly what you noticed.
If you like to look at the single threads of the coil, you have to use the single turn coil model (there is a check box to activate for multi-turn) or the RLC-coil model.
Regards Ueli