model Brush "Model considering voltage drop of carbon brushes"
extends Modelica.Electrical.Analog.Interfaces.OnePort;
parameter Machines.Losses.BrushParameters brushParameters "Brush loss parameters";
extends Modelica.Thermal.HeatTransfer.Interfaces.PartialElementaryConditionalHeatPortWithoutT(useHeatPort = false);
equation
if brushParameters.V <= 0 then
v = 0;
else
v = smooth(0, if brushParameters.ILinear < i then brushParameters.V else if i < -brushParameters.ILinear then -brushParameters.V else brushParameters.V * i / brushParameters.ILinear);
end if;
lossPower = v * i;
annotation (
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Documentation(info = "<html>\n<p>\nModel of voltage drop and losses of carbon brushes. For currents between <code>-ILinear</code> and <code>ILinear</code>\n the voltage drop shows a linear behavior as depicted in Fig. 1.\n For positive currents greater or equal than <code>ILinear</code> the voltage drop equals <code>V</code>.\n For negative currents less or equal than <code>-ILinear</code> the voltage drop equals <code>-V</code>.\n</p>\n\n<table border=0 cellspacing=0 cellpadding=1>\n <tr><td> <img src=\"modelica://Modelica/Resources/Images/Electrical/Machines/brush.png\"\n alt=\"brush.png\"> </td> </tr>\n <tr><td> <strong> Fig. 1: </strong>Model of voltage drop of carbon brushes</td> </tr>\n</table>\n<h4>Note:</h4>\n<p>\nThe voltage drop <code>v</code> is the total voltage drop of all series connected brushes.\n</p>\n\n<h4>See also</h4>\n\n<p>\n<a href=\"modelica://Modelica.Electrical.Machines.Losses.BrushParameters\">BrushParameters</a>\n</p>\n<p>\nIf it is desired to neglect brush losses, set <code>brushParameters.V = 0</code> (this is the default).\n</p>\n</html>"));
end Brush;