Coil interface does not function properly in Rotating machinery,Magnetic (rmm) interface

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Hello,

I am 3D simulating a changing magnetic field with rotating magnets. Everything works except the coil. I have simulated 3D coils with the magentic fields (mf)-interface and everything works fine with realistic results. But when I do the same in the (rmm)-interface, either the simulation does not converge or the induced voltage is unrealistic.

I applied the coil node to the 3D coil. Applied copper material and changed the coil to a homogenized multiturn coil with 100 windings. I also applied the Gauge fixing for A-field to the coil, else the simulation does not seem to work. The voltage is measured with the electrical circuit interface.

Study is: Coil Geometry Analysis, Stationary, Time Dependent.

The results are somewhat weird, the course of the induced voltage is correct and equals a cosine curve, the outer b-field is a sine curve. But the values are wrong. The B-field amplitude is roughly 1.5mT at 40Hz. The flux through an area with 5cm radius is roughly 9,42e-6 Wb, this does match with the simulated flux through the area. But the time derivative at 40Hz and 100 windings should have an amplitude of roughly 100mV, but the simulated voltage is only 0.26 mV.

The pictures show the 3d Coil, the b-field in the middle of the coil and the voltage.

Do you have any idea what might be wrong here?

Thanks for any advice.



0 Replies Last Post Sep 22, 2024, 3:11 a.m. EDT
COMSOL Moderator

Hello Felix Köster

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