At , Vector Fields, a Cobham company, will launch new capabilities for its groundbreaking design software for rotating electrical machinery.

The software is an application-specific version of the well known Opera package, and provides a front-end to the electromagnetic simulator that speeds design entry by means of 'fill in the blanks' dialog boxes.  Users select the form of motor or generator they want to design from a list of all common types, including induction, brushless permanent magnet and switched reluctance motors, and synchronous motors or generators.  Then, by simply entering a list of perhaps 10 parameters to define mechanical geometry, material properties and electrical data, the model is automatically created.  For example, the parameters might include diameters of rotor, stator, and shaft, stator tooth width and the number of stator slots. 

Among dozens of new model features added with this release is a much extended range of cage geometries for induction motors.  Users can now choose from six different starting points including circular, bullet and square - plus numerous potential variations and combinations of these shape elements. Induction motor stator design has also been made much more flexible with many options to define notch shapes on stator teeth as well as wedge geometries.  The choice of geometries for wound rotor synchronous motors has also been expanded in a similar way.  These new options give users the means to quickly arrive at a model, even for manufacturers who have their own proprietary design techniques.

If there are still any unusual features that need to be incorporated in designs, users also have open access to the scripting codes that generate the models, and can modify them at will to create a proprietary automated design process. A library of material properties is also included in the design software for speed, and is selected by means of a drop-down menu.  Again, if users employ any special material, such as an unusual grade of steel for laminations, then a new menu item can be created within minutes.

Using the scripts provided, motor or generator models can be generated within minutes.  Users can then simulate electromagnetic performance and view results such as the torque produced as a function of position, or the static analysis of flux linkage in the phases of the machine as a function of position and excitation. Design ideas can be trialled and optimised easily by varying the values of model parameters. 

"Finite element techniques allow users to simulate design concepts with supreme precision and accuracy, but it can take many hours to build a model of something as complex as a motor," says Alex Michaelides of Vector Fields.   "This software provides a precision virtual prototyping tool that allows searching 'what-if?' investigations to be performed in minutes, to identify the design characteristics of the perfect machine."

An automatic optimisation tool is also optionally available for Opera.  This intelligent tool automatically selects and manages multiple goal-seeking algorithms to find the best solution to a design problem, even if a user specifies several or even competing objectives.

A further advantage of the Opera tool for motor and generator design is the wider ability to simulate complete products.  Facilities include modelling the external circuit feed to the machine, as well as the mechanical load. Users have complete freedom to define the complex load behaviour for example, including friction, load and speed dependent torques.  'Multi-physics' capabilities available in the package additionally allow users to understand the effects of temperature rises, or the mechanical stresses that torque produced by the electric field will have on the machine's component parts.