Questions about modelling a sensor with a target wheel in Maxwell

[CheyenneXia]

Hi everyone,

I need to model a crank sensor with a flying wheel in Maxwell. Crank sensor is made of permenant magnet, pole piece (to concentrate the magnetic field), and coil. There is a space between the target wheel and the crank the sensor. What I have to do is to simulate the output signal from the coil while the flying wheel is spinning at certain speed and at a certain distance away from the sensor.

I am a new user of Maxwell. Up to now I know I could kindly simulate the wheel spinning by rotate certain angle. But still, I do not know how to simulate The Target Wheel's SPEED IN MAXWELL. Also, for this situation, how to put the excitation? As far as I understand, the magnetic source comes from the permenant magnet, because there is a relative motion between the wheel and the sensor, the coil has inducted current. Am I right? I select the winding and the coil terminal as the source. Am I right?

Thanks A LOT if anyone can help me.

Also, if someone have any tutorials about MAXWELL, please let me know. Up to now, I learn this software simply from the default examples and the online help. I have some experience in HFSS though.

Thanks,
Cheyenne

 

[gerbi]

Hi Cheyenne, I guess You have solved your problem so far ;) if not, here is my answer:

The principle of this device is the Faraday's Law (rotatnig field induces voltage in coil).
How to set this up ? In short..

1. Pick right solver. You have coil and rotation in model, you need to observe the signal.. only the Transient solver fits here.

2. Create the geometry. Assign materials (be careful when selecting the permanent magnet magnetic coercivity!). Set Eddy Effect in coil (Assign Excitation->Set Eddy Effect)

3. Set up motion. I use Maxwell v14 and I have option to set up a constant rotating speed or even a mechanical transient. I do not remeber how it was in earlier versions. Draw a circle (for 2D) or cylinder (for 3D) with rotating objects inside. Assign band to it (type-> Rotation, set up speed).

4. You have the coil.. You need to set up coil terminals (create a winding and add coil terminals to it) and external circut. Edit external circut in Maxwell Cicrut Editor. Create winding (name it the same as in Maxwell), grounding and whateever else You will need. Save it and export net list. Then you will need import the net list in Maxwell.

5. Define mesh operations on model. Air gap meshing is importand here. This step is quite hard, experience is essenial here.. You will need around 50k or more elements in an 'average' model for some good results.. up to 5 mil (complex), but it depends on computer, time, model geometry, needed accuracy..
(For first run use no mesh operations. See if it works).

6. Set up Analysis. Select start, stop time and time step. Choose wisely.. this will affect the accuracy of calculation but the time of simulation aswell. Set the time moment for which You want to save the solutions (Solve Setup->Save Fields)

7. Validate and run. It can take soem time, so be patient ;)

OK.. I guess that's all.. if not - ask

Ah yes.. the turtorial.. PM, i will send it to You