Revision history for BearingLoss


Revision [3257]

Last edited on 2020-12-17 18:14:22 by DavidMeeker
Additions:
src="https://www.femm.info/Archives/examples/femm40/brgloss_files/image002.gif"></sub></p>
src="https://www.femm.info/Archives/examples/femm40/brgloss_files/image004.gif"></sub></p>
src="https://www.femm.info/Archives/examples/femm40/brgloss_files/image006.gif"></sub></p>
src="https://www.femm.info/Archives/examples/femm40/brgloss_files/image008.gif"></sub></p>
src="https://www.femm.info/Archives/examples/femm40/brgloss_files/image010.gif"></sub></p>
href="https://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. <a href="http://octave.sourceforge.net/">Octave</a> is a matrix analysis program that is
script is used in conjunction with the OctaveFEMM package included in the <a href="https://www.femm.info/Archives/readme.htm">FEMM distribution</a>. This package allows Matlab or Octave to manipulate
href="https://www.femm.info/dmeeker/pdf/01333140.pdf">Effect of
href="https://www.femm.info/dmeeker/pdf/rotloss.pdf">Prediction of
Deletions:
src="http://www.femm.info/Archives/examples/femm40/brgloss_files/image002.gif"></sub></p>
src="http://www.femm.info/Archives/examples/femm40/brgloss_files/image004.gif"></sub></p>
src="http://www.femm.info/Archives/examples/femm40/brgloss_files/image006.gif"></sub></p>
src="http://www.femm.info/Archives/examples/femm40/brgloss_files/image008.gif"></sub></p>
src="http://www.femm.info/Archives/examples/femm40/brgloss_files/image010.gif"></sub></p>
href="http://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. <a href="http://octave.sourceforge.net/">Octave</a> is a matrix analysis program that is
script is used in conjunction with the OctaveFEMM package included in the <a href="http://www.femm.info/Archives/readme.htm">FEMM distribution</a>. This package allows Matlab or Octave to manipulate
href="http://www.femm.info/dmeeker/pdf/01333140.pdf">Effect of
href="http://www.femm.info/dmeeker/pdf/rotloss.pdf">Prediction of

Revision [1264]

Edited on 2014-08-05 22:36:17 by DavidMeeker
Additions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a concentric stationary cylinder is given in <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators."</p>
Deletions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a concentric stationary cylinder is given at <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators." This report also cites other works that used the same expression to get reasonable losses in real machines.</p>

Revision [1263]

Edited on 2014-08-05 22:28:31 by DavidMeeker
Additions:
<p>The windage model of NASA TN D-4849 is also implemented in the script to provide an estimate of windage losses. For this case, air at 20°C and 1 atm was assumed. In this case, a windage loss of 250W was calculated.</p>
Deletions:
<p>The windage model of NASA TN D-4849 is also implemented in the script to provide an estimate of windage losses. For this case, air at 20°C and 1 atm was assumed for the purposes of specifying the properties of air. In this case, a windage loss of 250W was calculated.</p>

Revision [1262]

Edited on 2014-08-05 22:26:43 by DavidMeeker
Additions:
<p>(Updated 06 Aug 2014 with windage)</p>
Deletions:
<p>Updated 06 Aug 2014 with Windage Calculations</p>

Revision [1261]

Edited on 2014-08-05 22:26:24 by DavidMeeker
Additions:
<p>07 Mar 2006</p>
<p>Updated 06 Aug 2014 with Windage Calculations</p>
<p>The windage model of NASA TN D-4849 is also implemented in the script to provide an estimate of windage losses. For this case, air at 20°C and 1 atm was assumed for the purposes of specifying the properties of air. In this case, a windage loss of 250W was calculated.</p>
Deletions:
<p>March 7, 2006</p>

Revision [1260]

Edited on 2014-08-05 22:19:36 by DavidMeeker
Additions:
\[Windage \, Loss = \pi C_d \rho r_o^4 \omega^3 L \]
<p> where \(\rho\) is the density of air; \(\omega \) is the speed of the rotor; \(L\) is the axial length of the rotor; and \(C_d\) is the drag coefficient of the rotor. The drag coefficient is obtained by solving the equation:</p>
\[ Re = \frac{r_o\,g\,\omega}{\nu}\]
Deletions:
\[Windage \, Loss = \pi C_d \rho R^4 \omega^3 L \]
<p> where \(\rho\) is the density of air; \(R\) is the outer radius of the rotor; \(\omega \) is the speed of the rotor; \(L\) is the axial length of the rotor; and \(C_d\) is the drag coefficient of the rotor. The drag coefficient is obtained by solving the equation:</p>
\[ Re = \frac{R\,g\,\omega}{\nu}\]

Revision [1259]

Edited on 2014-08-05 22:18:22 by DavidMeeker
Additions:
<p>where \(\Omega\) represents magnetic scalar potential and <i>A</i>
Deletions:
<p>where <i><span style='font-family:Symbol;'>W</span></i> represents magnetic scalar potential and <i>A</i>

Revision [1258]

Edited on 2014-08-05 22:16:43 by DavidMeeker
Additions:
\[Windage \, Loss = \pi C_d \rho R^4 \omega^3 L \]
\[\frac{1}{\sqrt{C_d}} = 2.04 + 1.768 \ln \left( Re \sqrt{C_d} \right) \]
<p> and Reynolds Number \(Re\) is defined as:</p>
\[ Re = \frac{R\,g\,\omega}{\nu}\]
<p> where \(\nu\) is the kinematic viscosity of air and \(g\) is the clearance between the rotor surface and the pole tips.</p>
Deletions:
\[Windage Loss = \pi C_d \rho R^4 \omega^3 L \]
\[\frac{1}{\sqrt{C_d}} = 2.04 + 1.768 \ln \left( Re \sqrt{} \right) \]
<p> and Reynold's Number \(Re\) is defined as:

Revision [1257]

Edited on 2014-08-05 22:13:30 by DavidMeeker
Additions:
\[Windage Loss = \pi C_d \rho R^4 \omega^3 L \]
Deletions:
\[Windage Loss = \( \pi C_d \rho R^4 \omega^3 L \]

Revision [1256]

Edited on 2014-08-05 22:13:03 by DavidMeeker
Additions:
\[Windage Loss = \( \pi C_d \rho R^4 \omega^3 L \]
Deletions:
<p>Windage Loss = \( \pi C_d \rho R^4 \omega^3 L \)</p>

Revision [1255]

Edited on 2014-08-05 22:12:27 by DavidMeeker
Additions:
<p> where \(\rho\) is the density of air; \(R\) is the outer radius of the rotor; \(\omega \) is the speed of the rotor; \(L\) is the axial length of the rotor; and \(C_d\) is the drag coefficient of the rotor. The drag coefficient is obtained by solving the equation:</p>
\[\frac{1}{\sqrt{C_d}} = 2.04 + 1.768 \ln \left( Re \sqrt{} \right) \]
<p> and Reynold's Number \(Re\) is defined as:
Deletions:
<p> where \(\rho\) is the density of air; \(R\) is the outer radius of the rotor; \(omega \) is the speed of the rotor; \(L\) is the axial length of the rotor; and \(C_d\) is the drag coefficient of the rotor.</p>

Revision [1254]

Edited on 2014-08-05 22:10:13 by DavidMeeker
Additions:
<p>Windage Loss = \( \pi C_d \rho R^4 \omega^3 L \)</p>
<p> where \(\rho\) is the density of air; \(R\) is the outer radius of the rotor; \(omega \) is the speed of the rotor; \(L\) is the axial length of the rotor; and \(C_d\) is the drag coefficient of the rotor.</p>
Deletions:
\(W = \pi C_d \rho R^4 \omega^3 L \)

Revision [1253]

Edited on 2014-08-05 22:07:34 by DavidMeeker
Additions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a concentric stationary cylinder is given at <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators." This report also cites other works that used the same expression to get reasonable losses in real machines.</p>
\(W = \pi C_d \rho R^4 \omega^3 L \)
Deletions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a concentric stationary cylinder is given at <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators."</p> This report also cites other works that used the same expression to get reasonable losses in real machines.

Revision [1252]

Edited on 2014-08-05 22:04:16 by DavidMeeker
Additions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a concentric stationary cylinder is given at <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators."</p> This report also cites other works that used the same expression to get reasonable losses in real machines.
Deletions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators."</p>

Revision [1251]

Edited on 2014-08-05 22:02:00 by DavidMeeker
Additions:
<p>Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf">NASA TN D-4849</a>, "Prediction of windage power loss in alternators."</p>
Deletions:
Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a [[http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf NASA TN D-4849]], "

Revision [1250]

Edited on 2014-08-05 22:00:14 by DavidMeeker
Additions:
<h3>Windage Losses </h3>
Aside from hysteresis and eddy current losses, windage losses are another significant component of rotating losses in magnetic bearings. An expression for windage loss on a rotating cylinder inside a [[http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680027690.pdf NASA TN D-4849]], "

Revision [889]

Edited on 2013-04-27 07:41:53 by DavidMeeker
Additions:
href="http://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. <a href="http://octave.sourceforge.net/">Octave</a> is a matrix analysis program that is
Deletions:
href="http://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. [[http://octave.sourceforge.net/ Octave]] is a matrix analysis program that is

Revision [888]

Edited on 2013-04-27 07:40:27 by DavidMeeker
Additions:
<p>This note describes the creation of an <a href="http://octave.sourceforge.net/">Octave</a> worksheet that
Deletions:
<p>This note describes the creation of an [[http://octave.sourceforge.net/ Octave]] worksheet that

Revision [887]

Edited on 2013-04-27 07:40:02 by DavidMeeker
Additions:
<p>This note describes the creation of an [[http://octave.sourceforge.net/ Octave]] worksheet that
href="http://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. [[http://octave.sourceforge.net/ Octave]] is a matrix analysis program that is
"mostly compatible with Matlab". This
Deletions:
<p>This note describes the creation of an Octave worksheet that
href="http://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. Octave is a matrix analysis program that is
“<a href="http://www.octave.org/">mostly compatible with Matlab</a>.” This

Revision [886]

Edited on 2013-04-27 07:37:51 by DavidMeeker
Additions:
script is used in conjunction with the OctaveFEMM package included in the <a href="http://www.femm.info/Archives/readme.htm">FEMM distribution</a>. This package allows Matlab or Octave to manipulate
Matlab/Octave’s support of matrices and complex numbers makes it easier to implement
Deletions:
script is used in conjunction with the OctaveFEMM package available from the
FEMM <a href="http://www.femm.info/Archives/readme.htm">website</a>. This package allows Octave to manipulate
Octave’s support of matrices and complex numbers makes it easier to implement

Revision [97]

Edited on 2009-08-06 15:01:06 by DavidMeeker
Additions:
href="http://www.femm.info/examples/brgloss/brgloss.m">brgloss.m</a>. Octave is a matrix analysis program that is
FEMM <a href="http://www.femm.info/Archives/readme.htm">website</a>. This package allows Octave to manipulate
href="http://www.femm.info/dmeeker/pdf/01333140.pdf">Effect of
href="http://www.femm.info/dmeeker/pdf/rotloss.pdf">Prediction of
Deletions:
href="http://femm.foster-miller.net/examples/brgloss/brgloss.m">brgloss.m</a>. Octave is a matrix analysis program that is
FEMM <a href="http://femm.foster-miller.net/Archives/readme.htm">website</a>. This package allows Octave to manipulate
href="http://femm.foster-miller.net/~dmeeker/pdf/01333140.pdf">Effect of
href="http://femm.foster-miller.net/~dmeeker/pdf/rotloss.pdf">Prediction of

Revision [96]

The oldest known version of this page was created on 2009-08-06 15:00:15 by DavidMeeker
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