Coil Modeling M6R305

with Infolytica Corporation May 25, 2000 We welcome your comments regarding Infolytica Corporation documents. Please send comments or corrections to the following addresses: email: docs@infolytica.com fax: Documentation Department 514.849.4239 post: Documentation Department Infolytica Corporation P.O. Box 1144 Station Place du Parc Montreal, Quebec H2W 2P4 Canada © Copyright 2000, Infolytica Corporation. Part number M6R305. All rights reserved. No part of this document may be reproduced, translated to another language, stored in a retrieval system, or transmitted in any form or by any means, electronic, photocopying, recording, or otherwise, without written permission from Infolytica Corporation. The information in this document is subject to change without notice. Table of Contents Introduction to coils in 2D models . . . . . . . . . . . . . . . . 1 2D translational geometry ..................................................................... 1 2D rotational geometry .......................................................................... 1 Direction of positive current flow ......................................................... 2 Choosing the direction of current flow . . . . . . . . . . . . . .2 Create a coil by selecting component surfaces ...................................... 3 Create a coil by selecting components .................................................. 4 Changing the direction of current flow . . . . . . . . . . . . .5 Coil page ................................................................................................ 5 Reverse the direction of current flow .................................................... 5 Coil property page ................................................................................. 6 Introduction to coils in 3D models . . . . . . . . . . . . . . . . 7 Creating coils ......................................................................................... 8 Create a coil by selecting a component ................................................. 8 Create a coil by selecting a surface of a component ............................. 8 Editing the properties of a coil .............................................................. 9 Coil modeling tips . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Coil forms ............................................................................................ 11 Model a coil normal to the current direction . . . . . . . .12 Draw the cross-section of the coil ....................................................... 12 Sweep the component .......................................................................... 12 Make the coil ....................................................................................... 13 Model a coil following the current direction . . . . . . . . .14 Modeling plan ...................................................................................... 14 Draw the rectangular cross-section ..................................................... 15 Make the first component .................................................................... 15 Make the second component ............................................................... 15 Make the third component ................................................................... 16 Make the last component ..................................................................... 16 Make the coil from a component ......................................................... 17 Modeling right-angle bends . . . . . . . . . . . . . . . . . . . 19 Sweeping normal to the current flow . . . . . . . . . . . . . .19 Sweeping in the direction of the current flow . . . . . . .21 Modeling plan ...................................................................................... 21 Draw the cross-section ........................................................................ 22 Make the first component .................................................................... 22 Tilt the surfaces of the first component ............................................... 23 Make the second component ............................................................... 24 Extract the edges of the end surface .................................................... 25 Move the construction slice ................................................................. 25 Make the component ........................................................................... 26 Tilt the surfaces of the second component .......................................... 26 Make the coil from a component ......................................................... 27 Modeling helical shapes . . . . . . . . . . . . . . . . . . . . . . 29 Distortion ............................................................................................. 29 Transformation .................................................................................... 29 Parameterization .................................................................................. 30 Using distortion and transformation . . . . . . . . . . . . . .31 Modeling plan ...................................................................................... 32 Set the preferred unit for length............................................................ 32 Draw the cross-section ........................................................................ 33 Make the first straight segment ........................................................... 33 Make the first half-turn ........................................................................ 34 Move the end of the half turn component ........................................... 34 Copy and transform Half Turn 1 ......................................................... 36 Re-name the copy ................................................................................ 37 Copy and transform Half Turn 2 ......................................................... 37 Create three more half turn components ............................................. 37 Create the end segment ........................................................................ 38 Make the coil ....................................................................................... 38 Using distortion and parameterization . . . . . . . . . . . .39 Modeling plan ...................................................................................... 39 Draw the cross-section ........................................................................ 40 Make the first straight segment ........................................................... 40 Make the half-turn ............................................................................... 40 Move the end of the half turn component ........................................... 41 Parameterize the sweep distance ......................................................... 42 Make the end segment ......................................................................... 43 Make the coil ....................................................................................... 43 1 �������� Introduction to coils in 2D models In 2D models, coils are created by selecting one or more components or component surfaces and then selecting the Make Coil command. The direction of positive current flow is determined by the method and sequence of selection. 2D translational geometry 2D rotational geometry If the geometry of the model is translational, a coil is usually created from a pair of components (coil sides). The coil sides are paired so that current flowing into the coil is matched by current flowing out of the coil. Note Although a coil usually has two coil sides, a 2D translational model can contain one or several coil sides. For example, symmetry conditions can allow for only one coil side. If the geometry of the model is rotational, the coil is usually defined by one component (coil side). The current flowing into a coil in a model with rotational geometry circles the axis of rotation and flows into the side of the device that is not modeled (but is understood to exist by MagNet). Note Although a coil usually has only one coil side, a 2D rotational model can contain two or more coil sides (for example, a helical coil). 2 Modeling Coils with MagNet Direction of positive current flow The direction of positive current flow in a coil side is displayed in the Coil page (after the symbol). In the example below, the positive current flows from Face#1 to Face#2. The connection between components that form the coil is shown in the Object page. In the example below, the positive current flows from Bar#1, Face#2 to Bar#2, Face#2. The direction of positive current flow can be changed in the Coil page or in the Coil property page. See “Changing the direction of current flow”. Choosing the direction of current flow In 2D models, coils are created by selecting one or more components or component surfaces and then selecting the Make Coil command. The direction of positive current flow is determined by: • The selection of components or of component surfaces • The sequence of selection After the coil is made, the direction of positive current flow can be changed using the Coil page or the Coil property page. See “Changing the direction of current flow”. Introduction to coils in 2D models 3 Create a coil by selecting component surfaces If you create a coil by selecting one or more component surfaces, the current flows into each component from each selected surface. After the coil is created, the current flow is indicated by patterns on the coil surfaces: current in (X), current out (O). 1st selected surface 2nd selected surface Current flow Current flow Current flow Start terminal End terminal 4 Modeling Coils with MagNet Create a coil by selecting components If you create a coil by selecting two components, the start and end terminals of the coil are assigned to the start surfaces of the two components selected. The positive current flow is from the start terminal (Terminal #1) to the end terminal (Terminal #2). Start surfaces 1st selected 2nd selected component component Current flow Start terminal End terminal Introduction to coils in 2D models 5 Changing the direction of current flow The direction of current flow in the coil sides (components) of a coil can be changed in the Coil page or in the Coil property page. Coil page The Coil page lists the terminals of the coil as well as the direction of current flow in each coil side (component) of the coil. Reverse the direction of current flow To reverse the direction of current flow, double-click the coil side in the Coil page. The order of the surfaces is reversed. When the direction of current flow is reversed, the pattern on the component surfaces changes: current in (X), current out (O). Coil side Current flow Current flow 6 Modeling Coils with MagNet Coil property page The Coil property page lists the direction of current flow for each coil side. To reverse the direction, click the Reverse Direction button. The property page, the Coil page, and the View window are automatically updated. 7 ��������� Introduction to coils in 3D models A coil is formed from a connected group of components. Each component of the group must share a start or end surface with another component. Coil components can be swept in the direction of current flow, or swept in a direction normal to the current flow. A coil component’s sweep direction can be different from other components in the coil, and also different from the rest of the model. Note When creating a coil that closes onto itself (e.g., racetrack) and that is swept normal to the direction of current flow, the coil must be made from at least two components. In cases where only a section of the coil is modeled, it is posible to make the coil from only one component. Shared surfaces between components Multiple sweep directions 8 Modeling Coils with MagNet Creating coils Coils are created by selecting either a component or a component surface and then selecting the Make Coil command. The method chosen to make the coil depends on how the coil has been swept and how you want the current to flow in the coil. Create a coil by selecting a component The direction of positive current flow is from the start terminal of the coil to the end terminal. When making a coil from a component, the start terminal of the coil is assigned to the start surface of the component selected to make the coil. The end terminal is assigned to the end surface of the last connecting component of the coil. Current flowing in the sweep direction. In the above diagram, where the coil begins and ends upon itself, the start and end terminals are adjacent. Create a coil by selecting a surface of a component When making a coil from a surface of a component, the start terminal of the coil is assigned to the surface selected to make the coil. The end terminal is assigned to the end surface of the last connecting component of the coil. Current flow and sweep direction Start terminal End terminal Introduction to coils in 3D models 9 The direction of positive current flow is from the start terminal of the coil to the end terminal. Note When creating a coil that closes onto itself (e.g., racetrack) and that is swept normal to the direction of current flow, the coil must be made from at least two components. In cases where only a section of the coil is modeled, it is posible to make the coil from only one component. Current flowing normal to the sweep direction. Editing the properties of a coil The Object page and the Coil page list the coils of the model. The coil properties are displayed in the Coil page and in the Coil property page. Current flow Sweep direction Start terminal End terminal 10 Modeling Coils with MagNet The properties of a coil include: Type: Solid Stranded Source:Current-driven Voltage-driven Current-driven:Number of turns (stranded) Current per turn (stranded) Total current (solid) Voltage-driven:Voltage External impedance Please see the on-line help for more information on editing coil properties. Coil modeling tips • Build all the components of the coil before you use the Make Coil command. Additional components cannot be added to the coil once the coil is made. • The sweep path of the coil components can be different from the sweep path of the model (MagNet meshes the coil separately). • The sweep path of the coil components can be different from each other. • When sweeping coil components in the direction of current flow direction, the cross-section of connecting components must be topologically equivalent. (The number of edges must be the same. Paired edges must be of the same type: lines or arcs.) Note Distortion is allowed (as long as the cross-section is topologically equivalent). Invalid (not topologically equivalent) Introduction to coils in 3D models 11 • To create helical-shaped coils, use the distortion and the transformation commands. See page 29 for more information. • When sweeping coil components in the direction of current flow, you can create a right-angled bend using the tilt parameters of a component. The tilt parameters extend the sweep of a component in a rotational direction. Please see page 19 for more information on creating right-angled bends. Coil forms MagNet meshes coils separately from the rest of the model. A coil form duplicates the shape of the coil and adds the shape to the model’s mesh. The coil form is filled with the material Virtual Air. After creating a coil, a coil form can be modeled to obtain the following results: • To reduce “smearing” effects on the current density distribution • To view a shaded or arrow plot on the coil • To calculate force or torque on a coil Note The coil form must follow the sweep direction of the rest of the model and is only required when using extrusion meshing. Please see the on-line help for more information on modeling coil forms. Tilted surfaces Tilted surfaces 12 Modeling Coils with MagNet Model a coil normal to the current direction In many cases, the simplest way to model a coil is to draw a cross-section of the coil (in the XY plane) and sweep the coil in the Z direction. You can then choose a side surface of a coil component as the start terminal of the coil. The current flows from the start to the end terminal of the coil. When drawing the geometry of the coil’s cross-section, it is necessary to create two lines, with one becoming the start terminal of the coil. For example, the geometry of a race-track shaped coil that will be swept normal to the current flow direction is shown below. Draw the cross-section of the coil • Draw the cross-section of the coil, adding two extra lines, one of which will become the start terminal. Sweep the component 1. Sweep the component. 2. Apply the material Copper: 5.77e7 Siemens/meter. 3. Name the component Racetrack. Creates terminal surface Current flow X Y Z Sweep direction Introduction to coils in 3D models 13 Make the coil 1. In the Object page, select the start terminal surface. 2. On the Model menu, click Make Coil. The coil is given the default name Coil#1 and is assigned default properties. The Object page and Coil page are updated. The next step is to edit the properties of the coil. Please see the on-line help for more information on editing coil properties. Selected surface 14 Modeling Coils with MagNet Model a coil following the current direction In some cases, it may be required to sweep the coil components in the direction of the current flow. In the model shown below, the racetrack coil is swept from a rectangular cross-section into four components: two straight sides and two curved ends. Modeling plan The modeling plan is outlined below. Current flow Z Y X Draw the rectangular cross-section page 15 Make the first component page 15 Make the second component page 15 Make the third component page 16 Make the last component page 16 Make the coil from a component page 17 Introduction to coils in 3D models 15 Draw the rectangular cross-section The coil must have the same cross-section throughout. In this case, the cross-section is rectangular. • Draw the rectangular cross-section using the following coordinates: Make the first component The first component is one of the straight sides of the coil. 1. Select the rectangular construction slice surface. 2. Sweep the component in a line 20 centimeters. 3. Apply the material Copper: 5.77e7 Siemens/meter. 4. Name the component Side 1. Make the second component The second component is one of the curved ends of the coil. 1. Select the end surface of Side 1. 2. Sweep the component in an arc using the following values: Angle: 180 Center: -10, 0 centimeters Axis vector: 0, -1 3. Apply the material Copper: 5.77e7 Siemens/meter. 4. Name the component End 1. Start coordinates -7, -4.5 End coordinates -5, -4.5 End coordinates -5, -3.5 End coordinates -7, -3.5 End coordinates -7, -4.5 16 Modeling Coils with MagNet Make the third component The third component is the other straight side of the coil. 1. Select the end face of End 1. 2. Sweep the component in a line 20 centimeters. 3. Apply the material Copper: 5.77e7 Siemens/meter. 4. Name the component Side 2. Make the last component The last component is the final curved end of the coil. 1. Select the end surface of Side 2. 2. Sweep the component in an arc using the following values: Angle: 180 Center: -10, 0 centimeters Axis vector: 0, -1 3. Apply the material Copper: 5.77e7 Siemens/meter. 4. Name the component End 2. The model should look like the diagram below. Introduction to coils in 3D models 17 Make the coil from a component When maki