Electromagnetic Analysis of a 2 Gap Solenoid Chapter 3 Workshop 2 Electromagnetic Analysis of a 2 Gap Solenoid

WS02: Emag Analysis of a 2 Gap Solenoid Workshop #2: Analysis of a 2 gap solenoid A DC solenoid consists of a coil wrapped around a permeable “U” shaped body and an armature. An analysis is performed to determine forces acting on both the body and the armature. Air gap Armature or keeper Coil Body March 4, 2005 Inventory #002210 3-2

WS02: Emag Analysis of a 2 Gap Solenoid Upon entering the workbench environment, choose new geometry. 1 March 4, 2005 Inventory #002210 3-3

WS02: Emag Analysis of a 2 Gap Solenoid Change the desired unit length to millimeters. 1 2 March 4, 2005 Inventory #002210 3-4

WS02: Emag Analysis of a 2 Gap Solenoid Read in the cad geometry file keeper0.iges and click on “generate”. 4 1 2 3 March 4, 2005 Inventory #002210 3-5

WS02: Emag Analysis of a 2 Gap Solenoid Bring up the winding tool. The “Center Plane” field of the Details box should be highlighted, prompting you to select a center plane which dimensions will reference. Choose the XYPlane and click apply. 2 1 3 March 4, 2005 Inventory #002210 3-6

WS02: Emag Analysis of a 2 Gap Solenoid Read in winding table file “keeper.txt” and click on Generate. 4 2 3 1: Click on box to the right of Winding Table File to bring up browser button (“…”). Click the browser button. March 4, 2005 Inventory #002210 3-7

WS02: Emag Analysis of a 2 Gap Solenoid You can visualize the coil cross section geometry define by the fields in the winding table by activating “Show Cross Section Solids”. 1 March 4, 2005 Inventory #002210 3-8

WS02: Emag Analysis of a 2 Gap Solenoid Increase the coil stack length to 50 mm and click generate. 2 1 March 4, 2005 Inventory #002210 3-9

WS02: Emag Analysis of a 2 Gap Solenoid Bring up the enclosure tool. The default “cushion” of 30 mm will suffice but you may increase it to 50 mm if you wish. VERY IMPORTANT! Change “Merge Parts” field to “yes”, otherwise the model will not solve (you will get an “invalid geometry message when attempting to do so). 3 1 2 3 CHANGE TO YES! March 4, 2005 Inventory #002210 3-10

WS02: Emag Analysis of a 2 Gap Solenoid Save the geometry to keeper.agdb. 1 2 3 March 4, 2005 Inventory #002210 3-11

WS02: Emag Analysis of a 2 Gap Solenoid Click on the Project tab and choose “New Simulation”. 1 2 March 4, 2005 Inventory #002210 3-12

WS02: Emag Analysis of a 2 Gap Solenoid Open “Geometry” in the tree on the left. Left click on any of the items labeled “solid” to see which part it represents (it will appear a solid green color in the plot). Right click on any of these items to produce the drop-down menu shown at right. Choose “Rename” and rename the parts as shown in the inset. 1 2 March 4, 2005 Inventory #002210 3-13

WS02: Emag Analysis of a 2 Gap Solenoid To prepare for assigning flux parallel boundaries on the exterior of the air, hide all other bodies. 1 (RMB) 2 March 4, 2005 Inventory #002210 3-14

WS02: Emag Analysis of a 2 Gap Solenoid To prepare for assigning flux parallel boundaries on the exterior of the air, hide all other bodies. 2 1 (RMB) 3 March 4, 2005 Inventory #002210 3-15

WS02: Emag Analysis of a 2 Gap Solenoid Activate face select mode. Hold down the CTRL button and use the LMB to select the three external surfaces facing you. Use the middle mouse button to rotate the geometry so the other three surfaces are facing you. Hold down the CTRL button and use the LMB to add them to the set to be made flux parallel. Click apply. 1 2 March 4, 2005 Inventory #002210 3-16

WS02: Emag Analysis of a 2 Gap Solenoid Define the per-turn current in the conductor to be 5 A as shown. 1 2 March 4, 2005 Inventory #002210 3-17

WS02: Emag Analysis of a 2 Gap Solenoid Insert a request for calculations of total flux density. 1 (RMB) 2 March 4, 2005 Inventory #002210 3-18

WS02: Emag Analysis of a 2 Gap Solenoid Insert a request for calculations of directional force/torque. 1 (RMB) 2 March 4, 2005 Inventory #002210 3-19

WS02: Emag Analysis of a 2 Gap Solenoid Assign the directional force/torque request to the keeper. Use the same procedure to define an additional request for x component forces on the poles and the back_bar. 2: Body pick mode 3 Select keeper 4 Apply to accept 1: Click on box to the right of “Geometry” to bring up Apply/Cancel buttons. 5 Request force in x direction March 4, 2005 Inventory #002210 3-20

WS02: Emag Analysis of a 2 Gap Solenoid Create the finite element mesh. If part “air” is hidden, you will see the mesh of the magnetic circuit shown here, but the mesh for all parts (including the air) will have been created. You may now solve the model. The solution will take about a minute. 4 1 (RMB) 2 3 Accept defaults March 4, 2005 Inventory #002210 3-21

WS02: Emag Analysis of a 2 Gap Solenoid Wireframe Display Vector/contour toggle Create a vector plot of the flux density. Experiment with the settings indicated at right to see how they affect the appearance of the display. 3D arrows Variable density Magnitude scaled 2D arrows March 4, 2005 Inventory #002210 3-22

WS02: Emag Analysis of a 2 Gap Solenoid Create a contour plot of the x component forces acting on the keeper and not the total (135.4 N). 1 2 March 4, 2005 Inventory #002210 3-23

WS02: Emag Analysis of a 2 Gap Solenoid Create a contour plot of the x component forces acting on the poles and back_bar and note the total (-143.5 N). Discrepancy between this value and that for the keeper may be due to (1) discretization and (2) force acting on the coil which cannot be accounted for in this analysis. We expect that: Fkeeper + Fpoles + Fcoil = 0 1 2 March 4, 2005 Inventory #002210 3-24

WS02: Emag Analysis of a 2 Gap Solenoid Tip: By default, the ANSYS files created during the solution process are NOT saved. It may be useful to save them so that operations not available in Simulation may be performed using ANSYS. For example, in ANSYS, a closed path around the magnetic circuit may be used to calculate magnetomotive force (MMF) to serve as a check on the specified coil current Ni: 1 2 ________________ SUMMARY OF MMF CALCULATION____________________ MMF = 5028.05354 Ampere Check: Ni = (1000t)(5A) = 5000 A-t NOTE: Parameter defined for magnetomotive force : MMF. ________________________________________________________________ Closed loop path March 4, 2005 Inventory #002210 3-25