To open Maxwell Circuit Editor:• Click Start>Programs>Ansoft>Maxwell 12>Maxwell Circuit Editor.The following menus are available in Maxwell Circuit Editor:
Related Topics:Schematic EditorMaxwell Circuit Editor Component ModelsPlacing Components in the Maxwell Circuit Editor SchematicAssigning Component Properties in Maxwell Circuit Editor
File menu
Edit menu
View menu
Project menu
Draw menu
Schematic menu
Maxwell Circuit menu
Tools menu
Window menu
Help menu
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Schematic EditorThe Schematic editor is the Ansoft tool for creating circuit schematics, or designs for a transient solution type. A design graphically represents and captures the electrical structure and characteris-tics of a circuit. You create such a design by starting the schematic editor and placing components, ports, connectors, and wires into a default empty schematic.
The Schematic Editor WindowThe Schematic Editor window allows you to place components and wire them together. You can move components by simply selecting and dragging them. Copy and paste can be used on compo-nents and their wires within the schematic editor.As you place the cursor near a pin of a component, it changes from an arrow to an X. This indicates that the schematic editor is in the wiring mode. In the wiring mode, click to start drawing a wire. Click again to end the wire.
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Commonly used items such as ports, n-port black boxes, grounds, and page connectors can be placed in the schematic by clicking their toolbar icons or by using the Draw menu.View controls to zoom in, zoom out, and fit the drawing to the editor window are available on the View menu, and on the shortcut menu that opens when you right-click in a schematic.The arrow keys scroll the view up, down, left, or right in small increments. The page up and page down keys scroll the view up or down in larger increments. If you scroll so far that no objects are in the view, select Fit Drawing from the View pull-down on the Maxwell top menu bar (or press Ctrl+D) to re-center the entire design, resized to fill the window.
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ComponentsA number of components are available in the Circuit simulator. To view the Components window in the project tree, click the Components tab. (The Project tab is visible by default when you first open Maxwell Circuit Editor.)To expand a component subgroup, double-click its book icon. To read about a specific component, double-click its information icon in the Help topic tree.The following types of elements are available in Maxwell Circuit Editor:• Dedicated Elements• Passive Elements• Probes• SourcesOnce components are placed in the schematic for a project, they appear in the project tree beneath the Project Components branch. The most recently placed components also appear under the Most Recently Used branch in the project tree. You can also set Favorites that can be accessed from the project tree.Related Topics:Placing Components in the Maxwell Circuit Editor SchematicAssigning Component Properties in Maxwell Circuit Editor
Dedicated ElementsThree dedicated elements are available in the Maxwell Circuit Editor project tree:• BarC: Commutator Bar• BarC_Model: Model Data for Commutator Bar• Winding: WindingThe text before the colon (:) represents the component name and can be changed in the Properties window once the component is placed in the schematic.Related Topics:Assigning Component Properties in Maxwell Circuit Editor
Commutator Bar and Commutator Bar ModelThe commutator bar element is intended to be used for the motor model with a commutator. This element models the variable (periodic) contact resistance between the brush and the commutator bars, as well as the switching (commutation of the current) that occurs when the brush makes con-tact with the two adjacent commutator bars. The element itself must always be used together with the corresponding commutator bar model. The commutator bar model can be dropped on the sheet anywhere and needs no connections. Only
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the commutator bar element itself should be connected as required by the application. The commu-tator bar elements need to reference the applicable commutator model.
Once the commutator bar element has been dropped on the sheet, you can double-click it to access the properties (make sure the Parameter Values tab is selected). Specify the applicable commuta-tor bar model name in the MOD line and also the Lag parameter in degrees. Lag identifies the angle the commutator bar has to rotate from TIME = 0 in the chosen sense of rotation until it is perfectly aligned with the brush. By defa1ult, the element ID and lagging angle in degrees are displayed next to the element.The commutator bar model needs to be dropped on the circuit sheet. It is unique for every commu-tator bar element. The commutator bar model contains the following parameters:• Model name that has to be referenced by all the commutator bar elements;• R, the full contact resistance between brush and commutator bar, regardless of which of the
two is wider;• WidB is the brush width in mechanical degrees;• WidC is the commutator bar width in mechanical degrees (does not include the insulation
between two adjacent bars);• Period is the angular periodicity of the positive (or negative) brushes; use 360 for a two pole
machine, 180 for a four pole machine with lap winding, etc.Related Topics:An Application of the Commutating Bar Element.
WindingThe winding element is used in the Maxwell Circuit Editor to create the necessary connection between the finite element model (the type of solution that supports the concept of winding, such as the transient type of analysis, with or without motion) and the driving circuits. It is necessary that the name(s) assigned for the winding(s) in the finite element model are matched exactly in the driv-ing circuit created in Maxwell Circuit Editor. Windings can be placed on the design sheet at any moment while you are creating the circuitry to be used to drive the finite element windings.
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To change the name of the winding placed on the sheet, click the winding symbol on the sheet, and change the name of the component in the property window (Value field in the DeviceName line, with the Param Values tab selected).
Passive ElementsThirteen passive elements are available in the Maxwell Circuit Editor project tree:• Cap: Capacitor• DIODE: Diode• DIODE_Model: Diode Model Data• Ind: Inductor• IndM: Mutual Inductance• Res: Resistor• SW_I: Current Controlled Switch• SW_I4: Current Controlled Switch with Controlling Port• SW_IModel: Model Data for Current Controlled Switches• SW_V: Voltage Controlled Switch• SW_V4: Voltage Controlled Switch with Controlling Port• SW_VModel: Model Data for Voltage Controlled Switches• Transformer: Ideal TransformerThe text before the colon (:) represents the component name and can be changed in the Properties window once the component is placed in the schematic.Related Topics:Assigning Component Properties in Maxwell Circuit Editor
Diode & Diode ModelDiode element must always be used together with a diode model. One diode model element can be used as reference for multiple diodes, as needed. Thus, once a diode is placed on the design sheet, a
Note The dot next to the winding symbol is used as the positive reference for the initial current (positive current is oriented from the "dotted" terminal towards to "un-dotted" terminal of the winding, through the winding).
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corresponding model must also be present on the sheet. Once both needed elements (diode and diode model) have been placed on the sheet, right mouse click the diode model and specify the parameters as required by the application. Then, right mouse click the diode and create the refer-ence to the corresponding model by entering the name of the model in the MOD line (Parameter Values tab should be selected). If you select the Show Hidden check box, the AREA diode param-eter (used below in the model definition) becomes visible. The default value of the AREA parame-ter is 1.The diode model used by Maxwell Circuit Editor is a static model as described by the following equation:
id is eVd Vt⁄
1–⎝ ⎠⎛ ⎞⋅ ibv e
Vd BV+( )Vt–⋅ vd gmin⋅+⎝ ⎠
⎛ ⎞–=
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where gmin = 1E-8 (fixed value) is added to improve convergence.
idrs
A
K
vd
+
- -
vt N kT( ) q⁄⋅=
q 1.6022 10 19– C⋅=
k 1.3807 10 23– J K⁄( )⋅=T is temperature in K, fixed at 300 K
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The model parameters are as follows:• IS is the saturation current in Amps.• RS is contact resistance in Ohms.• N is the emission coefficient.• EG is the barrier height at 0 K, in volts.• XTI is the diode saturation current temperature coefficient.• BV is the magnitude of the reverse breakdown voltage in volts.• IBV is the magnitude of the reverse breakdown current in amps.• TNOM is the reference temperature in Celsius.
Capacitor (CAP)A capacitor is assumed to be ideal (without losses or inductance) and is defined by the value of its capacitance (in the unit chosen by the user) and the corresponding initial condition (initial voltage). The straight bar of the capacitor symbol is used as the positive reference, and the curved bar of the capacitor symbol is used as a negative reference for the initial voltage (expressed in volts). The
is IS AREA eT TNOM 1–( )⁄( ) EG( ) vt⁄⋅ T
273 TNOM+---------------------------------⎝ ⎠⎛ ⎞
XTIN
---------
⋅ ⋅ ⋅=
ibv IBV AREA⋅=
rsRS
AREA---------------=
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default value of the initial voltage for all capacitors is zero. By default, the capacitance and element ID are displayed next to the component.
Resistor (Res)Resistor is assumed to be ideal (without inductive or capacitive effects) and is defined by the value of its resistance (in the unit chosen by the user, Ohm by default. By default the resistance and element ID are displayed next to the component.
Inductor (IND)Inductor is assumed to be ideal (without resistive or capacitive effects) and is defined by the value of its inductance (in the unit chosen by the user) and the corresponding initial condition (initial cur-rent). Note that the dot next to the inductor symbol is used as the positive reference for the initial current (positive current is oriented from the "dotted" terminal towards to "un-dotted" terminal of the inductor, through the inductor). The dot is also used to specify the mutual inductance between two or more inductors and thus determines the "polarized" terminals of the inductors. The default
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value of the initial current for all inductors is zero. By default the inductance and element ID are displayed next to the component.
Mutual Inductance (IndM)Mutual inductance is used to specify the inductive coupling between inductors. It is defined by specifying the IDs of the coupled inductors (always in pairs) and the coupling coefficient, a number between -1 and 1. The default value of the coupling coefficient is 0.95.
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Current Controlled Switch (SW_I)The current controlled switch comes in two flavors: with controlling port and without a controlling port. In either case a model data for the current controlled switch needs to be specified, similarly to the case of the diode.
Right-click the current controlled switch model and select Properties. With the Parameter Values tab selected, specify the switch model name (in the MOD line) as well as the ID of the controlling element: either an ammeter or a voltage source. In the later case the controlling quantity is the cur-rent through the voltage source. (Note that an ammeter is a voltage source with zero voltage, i.e. a short circuit).The current controlled switch with controlling port allows for the controlling quantity to be wired directly using connections with wires. In this case a reference arrow in the controlling port is dis-played and is internally used as current reference (positive current flow as indicated by the arrow).In the model for the current controlled switch the following parameters are used:• Ron is the resistance of the switch in the on state (0.001 ohms default value).• Roff is the resistance of the switch in the off state (1,000,000 ohms default value).• Ion is the "on" value of the controlling current in amps. If I>Ion, then R=Ron.
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• Ioff is the "off" value of the controlling current in amps. If I<Ioff, then R=Roff.
Voltage Controlled Switch (SW_V)The voltage controlled switch comes in two flavors: with controlling port and without a controlling port. In either case a model data for the voltage controlled switch needs to be specified, similarly to the case of the diode and current controlled switches.
Right-click the voltage controlled switch model and select Properties. With the Parameter Values tab selected, specify the switch model name (in the MOD line) as well as the ID of the controlling element: either a voltmeter or a current source. In the later case the controlling quantity is the volt-age across the current source. (Note that a voltmeter is a current source with zero current, i.e. an open circuit).
Note Setting ROFF = 0 in the voltage or current controlled switch model data changes the behavior of the device into a controlled conductance, according to the following equation:
where:
is a function describing the controlling signal -- a time, position, or speed dependent current source or voltage source. Equation (1) clearly shows that the magnitude of the conductance is dictated by both the value of RON and the magnitude of the control signal, while the time / position / speed dependency is dictated by the control signal itself.
G P( ) 1RON------------ fcontrol P( )⋅=
fcontrol P( )
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The voltage controlled switch with controlling port allows for the controlling quantity to be wired directly using connections with wires. In this case the reference for the voltage across the control-ling port is displayed by "+" and "-" symbols and the two symbols are internally used as voltage reference.In the model for the voltage controlled switch the following parameters are used:• Ron is the resistance of the switch in the on state (0.001 ohms default value).• Roff is the resistance of the switch in the off state (1,000,000 ohms default value).• Von is the "on" value of the controlling voltage in volts. If V>Von, then R=Ron.• Voff is the "off" value of the controlling voltage in volts. If V<Voff, then R=Roff.
TransformerThe transformer is an ideal element of infinite power without resistive or capacitive effects and lin-ear. It is defined the values of the primary and secondary inductances and the coupling coefficient between the two windings.
Note Setting ROFF = 0 in the voltage or current controlled switch model data changes the behavior of the device into a controlled conductance, according to the following equation:
where:
is a function describing the controlling signal -- a time, position, or speed dependent current source or voltage source. Equation (1) clearly shows that the magnitude of the conductance is dictated by both the value of RON and the magnitude of the control signal, while the time / position / speed dependency is dictated by the control signal itself.
G P( ) 1RON------------ fcontrol P( )⋅=
fcontrol P( )
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ProbesThree types of probes are available in the Maxwell Circuit Editor project tree:• Ammeter: Ammeter• Voltmeter: Voltmeter• VoltmeterG: Voltmeter with One Pin GroundedThe text before the colon (:) represents the component name and can be changed in the Properties window once the component is placed in the schematic.Related Topics:Assigning Component Properties in Maxwell Circuit Editor
AmmeterThe ammeter is an ideal element (equivalent with an ideal voltage source with zero voltage). An arrow is attached to the symbol so that a positive current measured by the ammeter flows as indi-cated by the arrow.No numerical value is needed, just the element ID and name may by altered by the user.
VoltmeterThe voltmeter is an ideal element with two pins (equivalent with an ideal current source with zero current). A plus sign is attached to the voltmeter symbol so that a reference for the voltage mea-sured by the voltmeter is possible. No numerical value is needed, just the element ID and name may by altered by the user.
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Voltmeter with One Pin Grounded (VoltmeterG)The voltmeter with one pin grounded is an ideal element with one pin, equivalent with an ideal cur-rent source with zero current. A plus sign is not necessary since it is assumed that the grounded pin (not available for connection in the circuit) is the negative one while the pin available for connec-tion is the positive one. Thus, the reference for the voltage measured by the voltmeter is possible. No numerical value is needed, just the element ID and name may by altered by the user.
Current and Voltage SourcesSources available in the Maxwell Circuit Editor can be defined such that in general the dependency of the current or voltage can be made function of time, position, or speed. The type of dependency is part of the properties of the respective source and is always user-selectable. Thus, in the equation defining the behavior of the source (when specified), the variable "t" can mean TIME or POSI-TION or SPEED as selected by the user for each application. The default dependency type is TIME. Twelve types of sources are available in the Maxwell Circuit Editor project tree:• IDC: DC Current Source• IExp: Exponential Current Source• IPulse: Pulse Current Source• IPWL: Piecewise Linear Current Source• ISffm: Sinusoidal Current Source• ISin: Sinusoidal Current Source• VDC: DC Voltage Source• VExp: Exponential Voltage Source• VPulse: Pulse Voltage Source• VPWL: Piecewise Linear Voltage Source• VSffm: Sinusoidal Voltage Source• VSin: Sinusoidal Voltage SourceThe text before the colon (:) represents the component name and can be changed in the Properties window once the component is placed in the schematic.Related Topics:
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Assigning Component Properties in Maxwell Circuit Editor
DC Current SourceThis is an independent (DC) current source. The default value of the current is zero. The arrow symbol shows the direction of the positive current flow through the current source.
Right-click the DC current source on the sheet, and select Properties to edit the features of the ele-ment:• On the Parameter Values tab, you can edit the value of the current and the status; status can
be active (default) but can be changed to Inactive_open or Inactive_short if desired.• On the General tab, you can set general features such as component name, component ID,
symbol name, etc.• On the Symbol tab, you can change the component color, location and spatial orientation,• On the Property Displays tab, you can edit the displayed features; by default the component
value (current in this case) and ID are displayed.
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Exponential Current SourceThis is an independent current source with an exponential waveform of the current as function of time as shown in the figure below. The arrow symbol shows the direction of the positive current flow through the current source.
Thus, the parameters of this exponential source are:• Initial current in Amps, I1;• Peak current in Amps, I2;• Rise time delay, Td1:
Text
Text
Y-Axis
X-Axis
I1
I1
I2I2
Td1 Td2
Tan2
Tan1
II
t
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• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Rise time constant, Tau1:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Fall time delay, Td2:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Fall time constant, Tau2:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
I
I2
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Pulse Current SourceThis is an independent current source with a trapezoidal waveform of the current as a function of time. The arrow symbol shows the direction of the positive current flow through the current source.
The parameters of a pulse current source are the following:• Initial current in Amps, I1;• Peak current in Amps, I2;
YAxis
X-AxistTd
Period
Tr TfPw
I1
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• Initial delay time, Td:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Rise time, Tr:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Fall time Tf:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Pulse width, Pw:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Pulse period, Period:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
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Piecewise Linear Current SourceThis is an independent current source with a piecewise linear waveform of the current as a function of time. The arrow symbol shows the direction of the positive current flow through the current source.
A piecewise linear current source is described by up to 20 pairs (Ti, Ii), where every pair of values specifies the value Ii in Amps of the current at time Ti in the following units:• In seconds if type is TIME.• In degrees if type is POSITION and type of motion is rotational.
Y-Axis
X-Axis t
(T1,I1)(T3,I3)
(T4,I4)
I
(T2,I2)
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• In geometry units if type is POSITION and type of motion is translational.• In rpm if type is SPEED and type of motion is rotational.• In geometry units per second if type is SPEED and type of motion is translational.
Frequency-Modulated Sinusoidal Current SourceThis is an independent current source with a single frequency modulated sinusoidal waveform of the current as a function of time. The arrow symbol shows the direction of the positive current flow through the current source.
The equation describing the waveform is:
where:• Io is Offset current in Amps.• Ia is the peak amplitude in Amps.• FC is the carrier frequency if type is TIME.• Mdi is the modulation index.• FS is the signal frequency if type is TIME.If the type is POSITION, the frequency should be calculated based on the respective spatial period-icity, taking into account the fact that "t" in the above equation is measured in degrees for rotational type of motion and in the user-defined geometry units for translational type of motion.If the type is SPEED, the frequency should be calculated based on the respective speed periodicity, taking into account the fact that "t" in the above equation is measured in rpm for rotational type of motion and in the user-defined geometry units per second for translational type of motion.
I t( ) I0 Ia 2π FC t⋅ ⋅( ) Mdi 2π FS t⋅ ⋅( )sin⋅+[ ]sin⋅+=
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Sinusoidal Current SourceThis is an independent current source with an exponentially damped sinusoidal waveform of the current as a function of time. The arrow symbol shows the direction of the positive current flow through the current source.
Y-Axis
X-Axis
eDf– t⋅
Ta
Td
t
I
Io
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where:• Io is Offset current in Amps.• Ia is the peak amplitude in Amps.• IFreq is the signal frequency if type is TIME.• Td is the delay time in seconds if type is TIME.• Phase is the signal phase delay if type is TIME.• Df is the damping factor in 1/seconds if type is TIME.If the type is POSITION, the frequency should be calculated based on the respective spatial period-icity, taking into account the fact that "t" in the above equation is measured in degrees for rotational type of motion and in the user-defined geometry units for translational type of motion. The delay and damping factor should also be interpreted accordingly.If the type is SPEED, the frequency should be calculated based on the respective speed periodicity, taking into account the fact that "t" in the above equation is measured in rpm for rotational type of motion and in the user-defined geometry units per second for translational type of motion. The delay and damping factor should also be interpreted accordingly.
DC Voltage SourceThis is an independent (DC) voltage source. The default value of the voltage is zero. The source exhibits a positive node, marked with the "+" sign, and a negative node, marked with the "-" sign. The positive current flows from the "+" node to the "-" node through the voltage source.
Right-click the DC voltage source on the sheet, and select Properties to edit the features of the ele-ment:• On the Parameter Values tab, you can edit the value of the voltage and the status; status can
be active (default) but can be changed to Inactive_open or Inactive_short if desired.• On the General tab, you can set general features such as component name, component ID,
I t( ) I0 Ia eDf t Td–( )–
2 π IFreq t Td–( ) Phase–⋅ ⋅ ⋅[ ]sin⋅ ⋅+=
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symbol name, etc.• On the Symbol tab, you can change the component color, location, and spatial orientation.• On the Property Displays tab, you can edit the displayed features; by default the component
value (voltage in this case) and ID are displayed.
Exponential Voltage SourceThis is an independent voltage source with an exponential waveform of the voltage as a function of time. The "+" and "-" symbols are used to mark the polarity of the source.
Text
Text
Y-Axis
X-Axis
V1
I1
I2V
Td1 Td2
Tan2
Tan1
V1
V2
V
t
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The parameters of an exponential voltage source are the following:• Initial voltage in Volts, V1.• Peak voltage in Volts, V2.• Rise time delay, Td1:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Rise time constant, Tau1:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Fall time delay, Td2:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Fall time constant, Tau2:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
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Pulse Voltage SourceThis is an independent voltage source with a trapezoidal waveform of the voltage as a function of time. The "+" and "-" symbols are used to mark the polarity of the source.
The parameters of a voltage pulse source are the following:• Initial voltage in Volts, V1.• Peak voltage in Volts, V2.
YAxis
X-AxistTd
Period
Tr TfPw
V
V2
V1
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• Initial delay time, Td:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Rise time, Tr:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Fall time Tf:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Pulse width, Pw:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
• Pulse period, Period:• In seconds if type is TIME• In degrees if type is POSITION and type of motion is rotational;• In geometry units if type is POSITION and type of motion is translational;• In rpm if type is SPEED and type of motion is rotational;• In geometry units per second if type is SPEED and type of motion is translational;
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Piecewise Linear Voltage SourceThis is an independent voltage source with a piecewise linear waveform of the voltage as a function of time. The "+" and "-" symbols are used to mark the polarity of the source.
A piecewise linear voltage source is described by up to 20 pairs (Ti, Vi), where every pair of values specifies the value Vi in Volts of the voltage at time Ti in the following units:• In seconds if type is TIME.• In degrees if type is POSITION and type of motion is rotational.• In geometry units if type is POSITION and type of motion is translational.
Y-Axis
X-Axis t
V
(T3,V3)
(T4,V4)
(T2,V2)
(T1,V1)
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• In rpm if type is SPEED and type of motion is rotational.• In geometry units per second if type is SPEED and type of motion is translational.
Frequency-Modulated Sinusoidal Voltage SourceThis is an independent voltage source with a single frequency modulated sinusoidal waveform of the voltage as a function of time. The "+" and "-" symbols are used to mark the polarity of the source.
The equation describing the waveform is:
where:• Vo is Offset voltage in Volts.• Va is the peak amplitude in Volts.• FC is the carrier frequency if type is TIME.• Mdi is the modulation index.• FS is the signal frequency if type is TIME.If the type is POSITION, the frequency should be calculated based on the respective spatial period-icity. taking into account the fact that "t" in the above equation is measured in degrees for rotational type of motion and in the user-defined geometry units for translational type of motion.If the type is SPEED, the frequency should be calculated based on the respective speed periodicity, taking into account the fact that "t" in the above equation is measured in rpm for rotational type of motion and in the user-defined geometry units per second for translational type of motion.
V t( ) V0 Va 2π FC t⋅ ⋅( ) Mdi 2π FS t⋅ ⋅( )sin⋅+[ ]sin⋅+=
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Sinusoidal Voltage SourceThis is an independent voltage source with an exponentially damped sinusoidal waveform of the voltage as a function of time. The "+" and "-" symbols are used to mark the polarity of the source.
Y-Axis
X-Axis
eDf– t⋅
Ta
Td
t
V
Vo
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where:• Vo is Offset voltage in Volts.• Va is the peak amplitude in Volts.• IFreq is the signal frequency if type is TIME.• Td is the delay time in seconds if type is TIME.• Phase is the signal phase delay if type is TIME.• Df is the damping factor in 1/seconds if type is TIME.If the type is POSITION, the frequency should be calculated based on the respective spatial period-icity, taking into account the fact that "t" in the above equation is measured in degrees for rotational type of motion and in the user-defined geometry units for translational type of motion. The delay and damping factor should also be interpreted accordingly.If the type is SPEED, the frequency should be calculated based on the respective speed periodicity, taking into account the fact that "t" in the above equation is measured in rpm for rotational type of motion and in the user-defined geometry units per second for translational type of motion. The delay and damping factor should also be interpreted accordingly.
V t( ) V0 Va eDf t Td–( )–
2 π IFreq t Td–( ) Phase–⋅ ⋅ ⋅[ ]sin⋅ ⋅+=
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Placing Components in the Maxwell Circuit Editor SchematicTo place a circuit component:1. Click the Components tab.
The Components window appears in the project tree.2. In the project tree, expand the Maxwell Circuit Elements branch.3. Expand the branch containing the component you want to place. The choices are Dedicated
Elements, Passive Elements, Probes, and Sources.4. Click to select the name of the component you want to place.5. Drag the component to the Schematic window.
A diagram of the component appears connected to the mouse pointer.6. Release the mouse button to place the component in the location you prefer.7. To place a second component of the same type, move the mouse pointer to another location,
and release it again.8. To exit from placement mode, do one of the following• To place the component a final time before exiting, press ENTER.• To exit without placing the component again, press SPACE.
Related Topics:Assigning Component Properties in Maxwell Circuit Editor
Hint To access these commands, you can also right-click and select one of the following from the shortcut menu: • Place and Finish• Finish
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Assigning Component Properties in Maxwell Circuit EditorOnce a component has been placed in the Schematic window, do the following to edit its proper-ties:1. Double-click the component.
The Properties window opens.2. Make the desired edits on the following four tabs:• Parameter Values• General• Symbol• Property Displays
3. Optionally, you can select or clear the Show Hidden check box on any of the Properties win-dow tabs.
4. Click OK.The specific properties differ per component, as seen in the help topics describing each circuit com-ponent.Each tab of the Properties window contains a list of parameters (each individual row) and proper-ties you need to set for each parameter (each column is a property).Related Topics:Placing Components in the Maxwell Circuit Editor SchematicCallback Scripting Using PropHost Object
Note Variables may be assigned to parameter values in the circuit by entering a variable name in the parameter value field and assigning a value in the Add Variable dialog box. Variables assigned in Maxwell Circuit Editor will be exported with the circuit and are available for modifying when the circuit is imported into another Ansoft application.
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Callback Scripting Using PropHost ObjectCallback scripts are scripts that can be set in the Property Dialog for individual properties by click-ing the button in the Callback column and choosing a script that is saved with the project. Callback scripts can contain any legal script commands including general Ansoft script function calls (e.g. GetApplication(), …). In addition, they can call functions on a special object named PropHost. The PropHost represents the PropServer (owner of properties) that contains the Property that is calling the Callback script. Therefore, the Callback script can use the PropHost's functions to query or set other properties in the same PropServer. Refer to the Property Level scripting commands for more information.Related Topics:Scripting Guide: Property Level Commands
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Opening the Online Help for Circuit ComponentsTo start the online help for any component from the schematic editor:1. In the Schematic editor, double-click the component for which you want to view help.The Properties dialog box opens. 2. Click the Parameter Values tab.3. Select the Value radio button.4. In the Info row, click the button in the Value column, as shown below for COAXSTEP:
The help viewer opens to display the component’s specifications.
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The driving circuit for the winding in this design consists of a voltage source in series with a resis-tor and with the winding. When complete, the circuit should look similar to the figure below.
To set up the external circuit, follow this general procedure:1. Add the circuit elements.2. Connect the circuit elements in series.3. Export the netlist.4. Save the Maxwell Circuit Editor project.5. Assign the external circuit.
Add the Circuit ElementsTo add the circuit elements in Maxwell Circuit Editor:1. Open the Maxwell Circuit Editor: Click Start>Programs>Ansoft>
Maxwell>Maxwell Circuit Editor.The Maxwell Circuit Editor program opens.
2. Click Project>Insert Maxwell Circuit Design.
Note One use for an external circuit can be to supply an excitation to a coil terminal, rather than using a voltage type of excitation.
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3. Click the Components tab in the project tree.4. Place the winding circuit element on the sheet:
a. In the project tree, under Maxwell Circuit Elements/Dedicated Elements, select the Winding element.
b. Drag it onto the sheet. c. Right-click, and select Finish to place the component. d. To view the properties, double-click the component in the Schematic window.
The Properties window appears.e. Change the Name to currentwinding, the same name you used when defining the wind-
ing in the Maxwell design.f. Click OK. g. Click Draw>Rotate, and position the winding vertically.
5. Place a resistor on the sheet: a. In the project tree, under Passive Elements, select Resistor.b. Drag the resistor onto the sheet. c. Right-click, and select Finish to place it where desired. d. Double-click the symbol of the resistor, change the value of the resistor, R, to 3.09, keep
the Unit value set to ohm, and click OK. The default is 100 Ohms.6. Place a voltage pulse on the sheet:
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a. In the project tree, under Sources select a VPulse element (Pulse Voltage Source).b. Drag it to the sheet, and then right-click and select Finish to place it onto the sheet. c. Double-click the source element symbol on the sheet, and then specify the following
source characteristics:
d. Leave the other fields set to the default values, and click OK.
Connect the Circuit Elements in SeriesTo connect the circuit elements in series:1. From within the Maxwell Circuit Editor, click Draw>Wire.2. Click each terminal. 3. When done, place the Ground symbol: Click Draw>Ground (or click the Ground symbol on
the toolbar), place the Ground symbol on the sheet, right-click, and select Finish to place the symbol.
4. Connect the ground to the circuit: Click Draw>Wire, and draw the final wire.
Export the NetlistTo export the netlist:1. From within the Maxwell Circuit Editor, click Maxwell Circuit>Export Netlist.
The Netlist Export dialog box appears.
2. Select the folder where you want to save the external circuit file.3. Type a name for the circuit in the File name box.4. Click Save.
The Netlist Export dialog box closes and the Maxwell Circuit Editor reappears.
Parameter Value Description
V1 0 Initial voltage
V2 5.97 Peak voltage
Tr 0.001 Rise time
Tf 0.001 Fall time
Pw 1 Pulse width
Period 2
Note To view the netlist before exporting it, click Maxwell Circuit>Browse Netlist.
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Save the Maxwell Circuit Editor ProjectTo save the project and exit Maxwell Circuit Editor:1. Click File>Save, type a name for the project, and click Save to save the Maxwell Circuit Edi-
tor project.2. Click File>Exit to close the Maxwell Circuit Editor program.
Assign the External CircuitTo assign the circuit in Maxwell (which should still be open):1. Click Maxwell>Excitations>External Circuit>Edit External Circuit.
The Edit External Circuit dialog box appears.2. Click Import Circuit.
The Select File dialog box appears.3. Select Designer Net List Files (*.sph) from the Files of type pull-down list.4. Browse to the location where you saved the circuit, select it, and click Open to import it. 5. Click OK to close the Edit External Circuit dialog box.
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Renaming a Source in Maxwell Circuit EditorTo rename a source that is drawn in the Schematic:1. Double-click the source.
The Properties dialog box appears.2. Click the Parameter Values tab (which should be the default tab visible).3. Change the text value in the Name row.4. Click OK.
The new name appears for the source label in the Schematic.
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Applying the Commutating Bar ElementThis paragraph describes how to apply the commutating bar element to simulate the commutating process of brush-type DC machines. A two-pole 12-slot PMDC motor, as shown in Fig. 1, is used as an example. The flux direction inside the S pole permanent magnet is from the air gap to stator yoke, and that of the N pole is from the stator yoke to the air gap.
The DC winding is of lap type with coil pitch of 5 slots. The flat-out extensional drawing of the motor indicating the relationship of permanent magnets, coils, commutating bars, and brushes at the initial position is shown in Fig. 2. With the rotation direction shown in Fig. 2, the brush aligned with the S pole is positive, and the brush aligned with the N pole is negative. The "go" terminal of
Fig. 1 The cross-section geometry of a PMDC motor
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coil0 connects to bar0, and its return terminal connects to bar1; the "go" terminal of coil1 connects to bar1, and its return terminal connects to bar2; and so on.
At the initial time, bar0 lags the positive brush by 15 mechanical degrees (a half commutating bar pitch), and it lags the negative brush by 195 mechanical degrees; bar1 lags the positive brush by -15 mechanical degrees, or 345 degrees, and it lags the negative brush by 165 mechanical degrees; and
Fig. 2 The flat-out extension of DC motor components
S N coil0 coil1
coil3
coil2
Rotation direction
-+bar0 bar1
bar2bar3
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so on. The functional connection of each commutating bar with the positive brush or negative brush is modeled by BarC (commutating bar) elements, as shown in Fig. 3 with ID number from 37 to 60.
Fig. 3 The external circuit with no-load operation
To negative brush
To positive brush
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In Fig. 3, elements with ID numbers of 37 to 48 represent the functional connections of bar0 to bar11 with the positive brush, respectively. Elements with ID numbers of 49 to 59 and 60 give the functional connections of bar1 to bar11, and bar0 with the negative brush, respectively. The addi-tional inductor in series with each coil inductance represents the end turn effect that is desirable to consider in a 2D model and possibly also in a 3D model that does not include the end turn geome-try. The additional series resistor in series with each coil represents the global resistance of the coil and needs to be included in both 2D and 3D simulations. The values between the BarC element symbols and ID numbers are the respective lagging angles in mechanical degrees. The element parameters can be edited by double-clicking on the element, as shown in Fig. 4.
Fig. 4 Parameters for BarC element
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In Fig. 4, the input value "ComModel" for MOD is the model name that defines the parameters of commutating bars and brushes. The parameters of ComModel can be edited by double-clicking the BarC_Model element, as shown in Fig. 5.
In this design, the commutator diameter is 24mm, and the brush width is 8mm. Therefore, the brush width in mechanical degrees is the following:
WidB = 2 * arcsin(8/24) = 38.9 (deg)The number of commutator bars is 12 (the same as the number of slots), and the commutator insu-lation thickness is 0.5mm. Therefore, the commutator bar width in mechanical degrees is the fol-lowing:
WidC = 360/12 - 2 * arcsin(0.5/24) = 27.6 (deg)
Note As a rule, each BarC element references a unique BarC_Model element.
Fig. 5 Parameters for BarC_Model element
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The electric conductance between a commutating bar and a brush varies with the rotor position and can be derived from the model parameters, as shown in Fig. 6, where Gmax = 1 / R.
In Fig. 6, LagAngle is treated as a BarC element parameter because it is different for different com-mutating bars. All other values (Gmax, WidB, WidC, and Period) can be obtained from BarC_Model parameters. Positions a, b, c, and d correspond to the positions when one side of a commutating bar (solid color) aligns to one side of a brush, as shown in Figs. 7 and 8.
Fig. 6 Electric conductance as a function of rotor position
Period LagAngle
Position
G
0 WidC+WidB
|WidC-WidB|
a
b c
d
Gmax
Fig. 7 Different conducting position when WidB > WidC
(a) (b) (c) (d)
Fig. 8 Different conducting position when WidB < WidC
(a) (b) (c) (d)
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The computed no-load induced voltage, taking into account the commutating process, is shown in Fig. 9.
Fig. 9 No-load induced voltage
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![Calibration of inductance standards in the Maxwell-Wien ... · A bridge circuit originally developed by J. C. Maxwell [1] 1 for use with ballistic detectors 'was adapted by M. Wien](https://static.documents.pub/doc/80x56/5ae8e4527f8b9a087790516e/calibration-of-inductance-standards-in-the-maxwell-wien-bridge-circuit-originally.jpg)
