within ;
model RotationalSpringSystem
  Modelica.Mechanics.Rotational.Components.Inertia inertia1(J=0.1, w(fixed=true,
        start=10))
    annotation (Placement(transformation(extent={{-40,-10},{-20,10}})));
  Modelica.Mechanics.Rotational.Components.Inertia inertia2(J=0.1, w(fixed=true,
        start=0))
    annotation (Placement(transformation(extent={{20,-10},{40,10}})));
  Modelica.Mechanics.Rotational.Components.Inertia inertia3(J=0.1, w(fixed=true,
        start=0))
    annotation (Placement(transformation(extent={{80,-10},{100,10}})));
  Modelica.Mechanics.Rotational.Components.SpringDamper springDamper1(c=1000, d
      =100) annotation (Placement(transformation(extent={{-10,-10},{10,10}})));
  Modelica.Mechanics.Rotational.Components.SpringDamper springDamper2(c=1000, d
      =1) annotation (Placement(transformation(extent={{50,-10},{70,10}})));
  Modelica.Mechanics.Rotational.Sources.Torque torque
    annotation (Placement(transformation(extent={{-70,-10},{-50,10}})));
  Modelica.Blocks.Sources.Step step(startTime=1)
    annotation (Placement(transformation(extent={{-100,-10},{-80,10}})));
equation
  connect(springDamper2.flange_b, inertia3.flange_a) annotation (Line(
      points={{70,0},{80,0}},
      color={0,0,0},
      smooth=Smooth.None));
  connect(inertia2.flange_b, springDamper2.flange_a) annotation (Line(
      points={{40,0},{50,0}},
      color={0,0,0},
      smooth=Smooth.None));
  connect(springDamper1.flange_b, inertia2.flange_a) annotation (Line(
      points={{10,0},{20,0}},
      color={0,0,0},
      smooth=Smooth.None));
  connect(inertia1.flange_b, springDamper1.flange_a) annotation (Line(
      points={{-20,0},{-10,0}},
      color={0,0,0},
      smooth=Smooth.None));
  connect(torque.flange, inertia1.flange_a) annotation (Line(
      points={{-50,0},{-40,0}},
      color={0,0,0},
      smooth=Smooth.None));
  connect(step.y, torque.tau) annotation (Line(
      points={{-79,0},{-72,0}},
      color={0,0,127},
      smooth=Smooth.None));
  annotation (
    uses(Modelica(version="3.2")),
    Diagram(coordinateSystem(preserveAspectRatio=true, extent={{-100,-50},{100,
            50}}), graphics),
    Icon(coordinateSystem(preserveAspectRatio=true, extent={{-100,-50},{100,50}})));
end RotationalSpringSystem;