QUESTION:
Can't you use TIMINT,OFF command in 3D transient EMAG to establish initial conditions (current distribution + field) when the conductor is modeled with keyopt(1)=1 (time integrated electric potential)?



ANSWER:
Here's an input file that shows initial conditions solved for in the first load step with TIMINT,ON (end time 1.000 s). The current is abruptly turned off in load step 2 (end time 1.0005 s). POST26 variable #2 is the current density in an arbitrary element; this decays rather gradually with time. Variable #3 is the TOTAL conductor current which is completely shut off after the second substep of load step 2. This is qualitatively consistent with expected behavior. The current will continue to flow into the conductor in some parts of the cross section, and out of the conductor in other parts of the cross section. The net current in load step 2 is zero, however it is nonzero at specific locations.


It is not clear why the time integrated electric potential will not give a solution with TIMINT,OFF. Perhaps this has to do with the fact that VOLT is NOT physical voltage but is instead the time integral of voltage. Another curious thing I noticed is that when loads are stepped (KBC,1) the first substep applies only half of the full value. I remember seeing this behavior perhaps 8 years ago and I never understood why ANSYS does this.


I am still awaiting reply from development on why this is so. The only thing I can suggest is to leave time integration effects on for the first load step used to establish the initial current and field when modeling conductors with the time integrated electric potental.


QUESTION:
Can't you use TIMINT,OFF command in 3D transient EMAG to establish initial conditions (current distribution + field) when the conductor is modeled with keyopt(1)=1 (time integrated electric potential)?



ANSWER:
Here`s an input file that shows initial conditions solved for in the first load step with TIMINT,ON (end time 1.000 s). The current is abruptly turned off in load step 2 (end time 1.0005 s). POST26 variable #2 is the current density in an arbitrary element; this decays rather gradually with time. Variable #3 is the TOTAL conductor current which is completely shut off after the second substep of load step 2. This is qualitatively consistent with expected behavior. The current will continue to flow into the conductor in some parts of the cross section, and out of the conductor in other parts of the cross section. The net current in load step 2 is zero, however it is nonzero at specific locations.


It is not clear why the time integrated electric potential will not give a solution with TIMINT,OFF. Perhaps this has to do with the fact that VOLT is NOT physical voltage but is instead the time integral of voltage. Another curious thing I noticed is that when loads are stepped (KBC,1) the first substep applies only half of the full value. I remember seeing this behavior perhaps 8 years ago and I never understood why ANSYS does this.


I am still awaiting reply from development on why this is so. The only thing I can suggest is to leave time integration effects on for the first load step used to establish the initial current and field when modeling conductors with the time integrated electric potental.





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