Machines
In electrical machines the operation of the machine involves motion, and generally the designer is interested in the production of motion by the interaction of electromagnetic fields (motoring) or the production of electricity by applying motion to an electromagnetic field (generating).
Induction (Asynchronous) Motors
This slip frequency can be used to design the motor using Opera-2d/ac and Opera-3d/Elektra-ss. Analysing over the range of frequencies between 0 Hz and supply frequency gives the torque v speed characteristic.
Voltage driven modeling is normally required and this gives the important current v speed characteristic. Non-linear solutions are vital for these machines, especially when closed rotor slots are present. The non-linear material option in Opera-2d/ac and Elektra-ss gives good results. Iron loss may also be important and the complex permeability option will provide a first order approximation for this.
The rotating modules Opera-2d/rm and Opera-3d/Carmen allow the effect of rotor and stator slotting, distributed windings etc. to be fully considered.
DC, PMDC and Universal Motors
DC motors, PMDC motors and Universal motors have a field pattern that is approximately stationary. Eddy currents are unimportant so Opera-2d/st and Opera-3d/Tosca are sufficient to calculate torque.
Opera-2d/st and Opera-3d/Tosca can be used to compute the torque at different current levels, including magnetic saturation, since eddy currents are ignored. Cogging torque may be computed using a snapshot approach using Opera-2d/st and Opera-3d/Tosca.
The rotating module Opera-2d/rm also has options to include mechanical load and/or use variable speed operation.
Synchronous Motors and Generators
Most design calculations can be performed assuming a coordinate system that moves synchronously with the rotor, using Opera-2d/st and Opera-3d/Tosca.
Under abnormal conditions (unbalanced load/supply, power system faults etc.), the negative sequence currents can be modeled using a time-varying field with static geometry approach using Opera-2d/ac and Opera-3d/Elektra-ss to produce a twice supply frequency travelling field in the stator.
To determine equivalent circuit parameters, a frequency response can be computed using Opera-2d/ac and Opera-3d/Elektra-ss.
Brushless DC, Stepper and Switched Reluctance Motors
The field distribution at various positions can be considered independent of previous positions. A snapshot approach can be used to determine the characteristics of the machine. In BLDC motors the torque vs. position and back EMF vs. position, and for switched reluctance and stepper motors, flux vs. current vs. position can all be computed with Opera-2d/st and Opera-3d/Tosca.
The rotating modules Opera-2d/rm and Opera-3d/Carmen may be useful for considering eddy currents induced in the permanent magnets of BLDC and hybrid steppers. The external circuit and mechanical coupling options in Opera-2d/rm enable the dynamic behaviour to be determined more precisely.
Structural and Thermal Aspects
Structural integrity and temperature rise also play important roles in determining the suitability of a design. The modules Opera-2d/th and Opera-3d/Tempo can be used for the thermal analysis, using eddy currents computed in other analysis modules as the heat sources. Both steady state and transient oprions are available.
The effects of stresses within the design can be computed using the Opera-2d/sa module. For 3D analysis, the forces can be exported to 3rd party stress analysis software.