[Getdp] problem with machine_magstadyn_a.pro
Joseph Frippiat
joseph_frippiat at voo.be
Mon Feb 15 00:00:02 CET 2016
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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