VM190
VM190
Ferromagnetic Inductor
Overview
| Reference: | S. J. Chapman, Electric Machinery Fundamentals, McGraw-Hill Book Co., Inc., New York, NY, 1985, pg. 14, ex. 1-1. |
| Analysis Type(s): | Static Magnetic Field Analysis (ANTYPE = 0) |
| Element Type(s): |
Tetrahedral Coupled-Field Solid Elements (SOLID98) 3D Infinite Boundary Elements (INFIN47) Current Source Elements (SOURC36) |
| Input Listing: |
VM190 requires a supplemental .cdb input file which is too long to include full input listings. This file must be downloaded and placed in your working directory for the test case to run properly. Additionally, the geometry and mesh should be regenerated. Download link: MAPDL Test Case Files for 2024 R2 vm190.cdb |
Test Case
A ferromagnetic core is wound with a 200-turn coil wrapped around one leg. Determine the mmf drop in the iron core for a coil current of 1 ampere.
| Material Properties | Geometric Properties | Loading | ||||||||
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Analysis Assumptions and Modeling Notes
Since the core material has finite permeability air is modelled to a small distance away from the core. The open boundary is modelled with an infinite surface element at the edge of the air region. The model employs 1/4 symmetry (about the Y and Z planes). The current source is modelled by a coil primitive. Dimensions of the coil are arbitrarily chosen since they have no bearing on the mmf calculations.
The iron core, linked by a coil, has no air-gap, hence a multiply-connected domain exists requiring the use of the Generalized Scalar Potential (GSP) formulation. The GSP strategy requires three solution steps, controlled by the MAGOPT command.
The mmf drop in the iron is calculated by a line integral around
the iron core. According to Ampere's law, 
H 
d
=l, where H is the field intensity, and I is the
enclosed current (or mmf drop). The integral is set up and calculated
using the path logic in POST1.
