aircore

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

OctaveFEMM Example: Air Core Coil Inductance Calculation

David Meeker

July 28, 2006

Introduction

As an example of the way that Octave can be use to automate calculations in FEMM, an Octave function is presented which uses FEMM to computes the inductance of a cylindrical air-cored coil of arbitrary dimensions. For comparison, an empirical formula for inductance is implemente…

alnicoproperties

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Alnico Properties Alnico magnet properties were gleaned from the following sources:

Grade

Demag Curve

Conductivity

LNG10

IMI

Arnold (Cast Alnico 2) 1.5 MS/m

LNG12

dmeeker@ieee.org

January 4, 2009

1 Introduction

For the purposes of developing an intuitive feel for the fashion in which energy is stored in a permanent magnet and its environment, it is useful to use analogies to other types of physical consideration. In this note, the magnetic circuit representation of a magnet dr…

axisymmetricformulation

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

FEMM Axisymmetric Interpolation Functions, Flux Density, and Element Matrices David Meeker 08Oct2021 Introduction The purpose of this note is to explain the somewhat unusual formulation used in FEMM's axisymmetric formulation. This is basically the method for first-order triangles considered in Section IV of Henrotte \(r^2\)\(r\)\(r=0\)\(\phi\)\(A\)\(\phi\)\[ \phi = 2 \pi r A\]\[s=r^2\]\((p,q)= (0,0),(1,0),(0,1)\)\((p,q)\)\((s,z)\)\[ \begin{eqnarray} s & = & (s_1 - s_0) p + (s_2 - s_0) q + …

bearingloss

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Calculation of Rotational Losses in Heteropolar Magnetic Bearings with FEMM

David Meeker

dmeeker@ieee.org

07 Mar 2006

(Updated 06 Aug 2014 with windage)

Introduction

An important advantage of magnetic bearings is their potential for reduced rotational losses relative to rolling element and fluid film bearings. To realize this potential, it is imp…

biasappendix

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Othogonality of Discrete Sine and Cosine Series The specific case of interest is the inner product: \[ \label{forceEq} f = p' \Lambda q \] where \(p\) and \(q\) are vectors defining the \(m^{th}\) and \(n^{th}\) harmonic of flux around a magnetic bearing rotor and \[ \label{lambdax} \Lambda = \mbox{diag}(\cos(\Theta) ) \] or \[ \label{lambday} \Lambda = \mbox{diag}(\sin(\Theta)) \] are diagonal matrices that define the contributions of each pole to the force in a particular force direction wher…

biasredux

Anonymous (anonymous@undisclosed.example.com) — 2026-04-10T17:12:59+00:00

Bias Current Linearization Revisited Abstract: Previously, a generalized bias current linearization was presented for the control of radial magnetic bearings. However, a numerically intensive procedure was required to obtain bias linearization currents. The present work develops an analytical solution to the generalized bias linearization problem in which solutions are indexed by a small number of parameters. The formulation also permits the analytical computation of bias linearization curren…

blockedimpedance

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Loundspeaker Blocked Impedance David Meeker 01Nov2015 Introduction As of the 2015Oct25 test build of FEMM, the program has the capability to perform incremental linearized AC solutions about a DC operating point. One of the main uses of this new functionality is to aid in the analysis of loudspeakers, where the coil imposes a small magnetic field on top of the DC field imposed by the loudspeaker's permanent magnet. [][]^o⁰\(\mu_r\)\(\omega\)\(\delta\)…

blockedimpedance1khz

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Blocked Impedance Results at 1kHz Variation of the BlockedImpedance problem where the impedance and inductance of the SSF-082 loudspeaker are analyzed at 1kHz across a range of positions. Since the frequency is low (relative to 20kHz), a coarser surface mesh of 0.05mm can be used on the low carbon steel parts. Two configurations are considered: one with no shorting ring, and one with a copper shorting ring around the central pole. Z_L(jω)L_eff(f)ωR_eff…

bondedneoproperties

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Bonded NdFeB Magnet Properties Bonded NdFeB properties defined in FEMM are meant to be representative of typical examples rather than strictly based on the products from one vendor. Since bonded magnets consist of permanent magnet powder with a polymer binder, the electrical conductivity is very low. A typical value of electrical conductivity is 0.01 MS/m.\[\mu_r = 1.06 + 0.02 \left( \frac{bhmax}{\mbox{MGOe}} \right)\]

Grade

\(BH_{max}\), MGOe

\(…

catalina

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

.zip archive of files that might facilitate running on macOS Catalina in conjunction with WINE Maybe the VC2008 64-bit redistributable is also needed--I'm not sure whether that installer will run. * [femm42.zip] * [vcredist_x64.exe]

coilgun

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Lua Scripting Example: Coil Gun

David Meeker

dmeeker@ieee.org

June 10, 2004

1. Introduction

This example considers the computation of the force on an iron ball at various positions relative to a wound, air-cored coil. The configuration is similar to some coil guns that are de…

complexlua

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Lua 4.0 compiled with complex numbers as the standard number type David Meeker dmeeker@ieee.org 01Dec2005 This is a modified version of Lua 4 (see ) that uses the CComplex class from FEMM as the standard number type in Lua. The distribution contains a project for building a statically linked version of the Lua library and a dialog-based interpreter program for evaluating expressions in Lua 4. The package builds with Visual C++LuaConsole++

computationalmagneticslinks

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Professional Societies * IEEE Magnetics Society * International Compumag Society * Compumag TEAM Homepage * Japan Society of Applied Electromagnetics and Mechanics * Magnetics Society of Japan * UK Magnetics Society * APS Topical Group on Magnetism Journals * IEEE Transactions on Magnetics * IEEE Magnetics Letters * IEEE Transactions on Industry Applications * IET Science, Measurement & Technology * COMPEL * Actuators Online Resources * Lund University Desig…

contrib

Anonymous (anonymous@undisclosed.example.com) — 2026-05-04T01:20:24+00:00

Examples, Documentation, and Tools Contributed by FEMM Users * Modified Halbach Arrays * Coreless Three-Phase Alternator * PeMSyn Permanent Magnet Synchronous Machine design tool * Japanese translation of FEMM magnetics tutorial * AplX scripting example [femm_mo_getpointvalues.atf] * image2coordinates Matlab toolbox * DoSA-2D (Designer of Solenoids & Actuators) * M…

contribanimation

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

FEMM Animation Lua Script by H.M.Wassim It is as easy as pasting the script to the Lua console then evaluating. You can adjust the settings if you want to. This script is developed to create sequence of screenshots for each phase angle. I hope this would somehow help someone someday.

corelessalternator

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Coreless Three-Phase Alternator José Borges de Almeida Universidade do Minho Physics Department 30Mar2021 Introduction This note describes the modeling of an alternator for a small wind turbine; the rated power is about 500 W, at 1800 rpm, and it presents no cogging or starting torque, meaning that it will start rotating even with the tiniest breeze. Most permanent magnet alternators are classified as either inner or outer rotor, but the present one is both inner and oute…

corelosscalculation

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Rotating Losses in a Outrunner Doubly Salient Permanent Magnet Generator David Meeker 09Sept2009 Companion Files: getloss.zip 1 Introduction This note will consider the analysis of an “outrunner” (rotor on the outside) single-phase doubly salient permanent magnet machine. This machine is interesting from the point of view of core loss computation because the rotor and stator iron are both laminated and see different dominant frequencies. This example will show how a seri…

csharp

Anonymous (anonymous@undisclosed.example.com) — 2026-05-03T22:45:35+00:00

Dave, Following the C# code which can access FEMM. I used the C# 2008 express edition. In the case of distributing for the general users, feel free. Anderson Nunes using System; using System.Collections.Generic; using System.Linq; using System.Text; using Femm; namespace CallFEMM { static class Programa { static void Main(string[] args) { ComandosFEMM enviarFEMM = new ComandosFEMM(); string texto = enviarFEMM.Prompt("Write a text").Replace("\n",); bool te…

davidmeeker

Anonymous (anonymous@undisclosed.example.com) — 2026-05-04T01:19:22+00:00

Finite Element Method Magnetics

acforceexample

acloss

activex

activexclient

aircore

OctaveFEMM Example: Air Core Coil Inductance Calculation

Introduction

alnicoproperties

1 Introduction

axisymmetricformulation

bearingloss

Calculation of Rotational Losses in Heteropolar Magnetic Bearings with FEMM

Introduction

biasappendix

biasredux

blockedimpedance

blockedimpedance1khz

bondedneoproperties

catalina

coilgun

Lua Scripting Example: Coil Gun

complexlua

computationalmagneticslinks

contrib

contribanimation

corelessalternator

corelosscalculation

csharp

davidmeeker