[Getdp] problem with machine_magstadyn_a.pro

[Joseph Frippiat]

I've found the problem and it's all mine...

The speed of the rotor was decreasing but the speed of the region 
Rotor_Moving was kept contant with

             ChangeOfCoordinates[ NodesOf[Rotor_Moving], 
RotatePZ[delta_theta[]]];

because delta_theta[] was defined like this:

             delta_theta[] = delta_theta_deg * deg ;

I've defined a new function my_delta_theta[] like this:

             my_delta_theta[] = delta_time * $1; // $1 is the current 
rotation speed

And region Rotor_Moving is rotated with

             ChangeOfCoordinates[ NodesOf[Rotor_Moving], 
RotatePZ[my_delta_theta[$Velocity]]];

$Velocity is computed in the PostOperation Mechanical.

And this is the proof :



Very very nice software, so powerful :-)

Joseph

Le 13/02/2016 12:38, Joseph Frippiat a écrit :
> I'm modeling a rotating eddy current brake whith Onelab and the 
> library machine_magstadyn_a.pro .
>
> My problem is that the torque does not drop when the rotor speed 
> decreases to 0 rpm...
>
> In the model, the smooth solid steel rotor is outside and the stator 
> is inside.
>
> I give an initial speed to the rotor and I apply a dc voltage to the 
> windings of the stator.
>
> 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) :
>
>     Equation {
>       GlobalTerm { DtDof [ Inertia * Dof{V} , {V} ] ; In DomainKin ; }
>       GlobalTerm { [ Friction[] * Dof{V} , {V} ] ; In DomainKin ; }
>       GlobalTerm { [        Torque_mec[] , {V} ] ; In DomainKin ; }
>
>       If(Flag_MachineType) // Motor
>         GlobalTerm { [      -Torque_mag[] , {V} ] ; In DomainKin ; }
>       Else // Generator
>         GlobalTerm { [       Torque_mag[] , {V} ] ; In DomainKin ; }
>       EndIf
>
>       GlobalTerm { DtDof [ Dof{P} , {P} ] ; In DomainKin ; }
>       GlobalTerm {       [-Dof{V} , {P} ] ; In DomainKin ; }
>     }
>
> Joseph
>

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