Learning Forum

[HFarag11]

Hello,

I am trying to design a differential probe to detect a defects on a plate using Eddy currents. The probe consists of a driver coil to induce the eddy currents and two sensing coils to sense the defect. I need to assign Number of winding as 150 but i can't do that without assigning either current or voltage or external circuit to the winding. In case of sensing coils , i can't assign either the current or the voltage because it will be acting as a source. so, in that case, is it possible to assign external circuit(sensing circuit) to the winding of the sensing the coil so that the coils will act as sensors? Is there any other way to design or define the coil as sensing coils. 

Thanks 

[Dennis Steward]

Hi HFarag11,

You've got the right idea.  Set up the sensing coil as an external winding instead of a voltage or current source.

In the external circuit, you can then add whatever lumped elements you like to the coil to act as a load.

A winding in an external circuit does not have to be driven by a source component; it can be passive.

Place a voltage or current probe in the external circuit and you can post process the induced values in the Eddy solver.

If you want to see a sinusoidal output, graph the induced quantity vs. phase angle instead of frequency.

One other way to do this would be to use the transient solver which permits arbitrary excitations , but will take longer to solve.

Take Care,

Dennis

[HFarag11]

Dear Dsteward,

Thanks for your reply. I did add a voltmeter probe in the external circuit and attached it to the winding but an error appears when i try to import the netlist. it only accept a resistor to be attached to the winding. I attached a picture of the circuit i tried to add to the winding which gives me the error.

[Dennis Steward]

Hi HFarag11,

Try using the other Voltmeter component (one pin grounded) and place a large resistor in series with the ground node.

Here's a circuit that I used in a similar model:

 

[HFarag11]

Hello Dsteward,

I did the same circuit you sent but it gives me an error saying that the ground is placed improperly when i try to import it. i am pretty sure that the ground is connected, but i don't know why it gives me that error?

Heba 

[Dennis Steward]

Hi Heba,

If you're not sure if the ground is connected, drag the ground symbol around a bit and make sure that it stays connected to the rest of the circuit.

Your model should work. So please let me see the exact error messages the you're receiving for different circuit topologies.

Also, what version of Maxwell are you using?

Additionally, you'll find some great tutorials here: https://www.youtube.com/channel/UCGfupEFC34BNIqKlCGUKwEA

Have a look at the transient solver examples since they are similar to the external circuit modeling int he Eddy Solver.

Take Care,

Dennis

 

[HFarag11]

Dear Dennis,

Thank you so much for your help. I figured out the problem. When i choose update Netlist from circuit, it shows that it is imported successfully. Really appreciate your patience and help.

Heba