<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">I've found the problem and it's all
mine...<br>
<br>
The speed of the rotor was decreasing but the speed of the region
Rotor_Moving was kept contant with<br>
<br>
ChangeOfCoordinates[ NodesOf[Rotor_Moving],
RotatePZ[delta_theta[]]];<br>
<br>
because delta_theta[] was defined like this:<br>
<br>
delta_theta[] = delta_theta_deg * deg ;<br>
<br>
I've defined a new function my_delta_theta[] like this:<br>
<br>
my_delta_theta[] = delta_time * $1; // $1 is the
current rotation speed<br>
<br>
And region Rotor_Moving is rotated with<br>
<br>
ChangeOfCoordinates[ NodesOf[Rotor_Moving],
RotatePZ[my_delta_theta[$Velocity]]];<br>
<br>
$Velocity is computed in the PostOperation Mechanical.<br>
<br>
And this is the proof :<br>
<br>
<img src="cid:part1.07060100.08050303@voo.be" alt=""><br>
<br>
Very very nice software, so powerful :-) <br>
<br>
Joseph<br>
<br>
Le 13/02/2016 12:38, Joseph Frippiat a écrit :<br>
</div>
<blockquote cite="mid:56BF15B7.9020609@voo.be" type="cite">I'm
modeling a rotating eddy current brake whith Onelab and the
library machine_magstadyn_a.pro .
<br>
<br>
My problem is that the torque does not drop when the rotor speed
decreases to 0 rpm...
<br>
<br>
In the model, the smooth solid steel rotor is outside and the
stator is inside.
<br>
<br>
I give an initial speed to the rotor and I apply a dc voltage to
the windings of the stator.
<br>
<br>
In the original formulation, Torque_mag tends always to accelerate
the rotor. That's why I've modified lightly the mechanical
formulation like this (the machine is a generator) :
<br>
<br>
Equation {
<br>
GlobalTerm { DtDof [ Inertia * Dof{V} , {V} ] ; In DomainKin
; }
<br>
GlobalTerm { [ Friction[] * Dof{V} , {V} ] ; In DomainKin ;
}
<br>
GlobalTerm { [ Torque_mec[] , {V} ] ; In DomainKin ;
}
<br>
<br>
If(Flag_MachineType) // Motor
<br>
GlobalTerm { [ -Torque_mag[] , {V} ] ; In DomainKin ;
}
<br>
Else // Generator
<br>
GlobalTerm { [ Torque_mag[] , {V} ] ; In DomainKin ;
}
<br>
EndIf
<br>
<br>
GlobalTerm { DtDof [ Dof{P} , {P} ] ; In DomainKin ; }
<br>
GlobalTerm { [-Dof{V} , {P} ] ; In DomainKin ; }
<br>
}
<br>
<br>
Joseph
<br>
<br>
</blockquote>
<br>
</body>
</html>