### Calculate magnetic torque

Posted:

**05 Sep 2016, 16:46**Hi everyone!

I have some Problem with the calculation of magnetic torque. I found 2 possibilities in Elmer:

1. as a component:

2. as a group

My problems are so far:

1. When i use coordinate scaling=1e-3 a point at 100mm in x-direction is still Torque Group Origins(1,3) = Real 100 0 0?

2. Whats the right way when i want a torque axis from f.e. A=(10 20 -30) to b=(10 20 30):
or
?

Thank you in advance!

I have some Problem with the calculation of magnetic torque. I found 2 possibilities in Elmer:

1. as a component:

Code: Select all

```
Component 1
Name = string "metal"
Master Bodies(1) = integer 4
Torque Origin(3) = Real 100 0 -100
Torque Axis(3) = Real 0 0 100
Calculate Magnetic Force = Logical True
Calculate Magnetic Torque = Logical True
End
```

Code: Select all

```
...
Body 4
Target Bodies(1) = 4
Name = "Body 4"
Equation = 1
Material = 1
Body Force = 2
Torque Groups(1) = integer 1
End
...
Solver 3
Equation = MgDynPost
Potential Variable = AV
Calculate Current Density = True
Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
Calculate Electric Field = True
Calculate Magnetic Field Strength = True
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-7
Nonlinear System Max Iterations = 20
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Iterative
Linear System Iterative Method = CG
Linear System Max Iterations = 5000
Linear System Convergence Tolerance = 1.0e-10
BiCGstabl polynomial degree = 2
Linear System Preconditioning = Diagonal
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = False
Linear System Residual Output = 1
Linear System Precondition Recompute = 1
Torque Group Origins(1,3) = Real 100 0 0
Torque Group Axes(1, 3) = Real 0 0 1
Calculate Electric Field = True
Calculate Magnetic Field Strength = True
Calculate Nodal Forces = Logical True
End
```

1. When i use coordinate scaling=1e-3 a point at 100mm in x-direction is still Torque Group Origins(1,3) = Real 100 0 0?

2. Whats the right way when i want a torque axis from f.e. A=(10 20 -30) to b=(10 20 30):

Code: Select all

```
Torque Origin(3) = Real 10 20 -30
Torque Axis(3) = Real 0 0 30
```

Code: Select all

```
Torque Origin(3) = Real 10 20 -30
Torque Axis(3) = Real 10 20 30
```

Thank you in advance!