Skip to main content

Hello, Motor Fans:

In this blog I show how to use the Lab Module to develop Efficiency Maps, Other Maps, apply Duty Cycles, and calculate Operating Points. Also, Open Circuit and Short Circuit tests are performed and results are discussed. 



We will use an IPM motor for the example. Navigate to the file highlighted below.



Efficiency Map

Efficiency, EM Torque, Core Loss, Solid Loss, Voltage, Current, Total Loss, Winding Loss, Mechanical Loss, Power Factor, Input Power, Output Power

The example file has all settings configured. The efficiency map is made in the Lab Module. However, if creating a new project

  • Go to the Emag module >> Input Data >> Settings >> Losses >> AC Winding >> set the AC winding Losses Model.
  • In the Lab Module build the model, configure the calculation settings, and apply the mechanical loss model settings (bearings, windage, and custom).
  • In the Lab Module go to the Electromagnetics Tab, select Efficiency Map for the Calculation Type and Smooth Map for the Calculation Option. Set the parametric sweep definitions for the Speed and Current. 

Select Calculate Emagnetic Performance and then the Efficiency Map will appear in the Lab Viewer.


The quantities of the Efficiency Map are

  • Shaft Torque plotted on the Y Axis.
  • Speed is plotted on the X Axis.
  • Efficiency plotted on the Z Axis.


The family of Torque Speed Curves used to produce the Efficiency Map can be displayed by un-checking the Contour Mode tab in the Lab Viewer.


Other quantities instead of Efficiency can be plotted on the Z Axis can by going to Graph Settings >> Plot Selection and choosing the z parameter quantity. There are more quantities to choose form than shown below.



Efficiency Map Duty Cycle Operating Points

We can choose a Duty Cycle (Drive Cycle) to analyze motor performance. The drive cycles available to choose to use in Motor-CAD are shown below. However, you may select Custom Duty Cycle instead to import a file.


In this example HWY (Highway) drive cycle is chosen. Select Calculate Duty Cycle Performance. 


The plot will appear in the Lab Viewer as shown below.



In the Calculation tab the Motor/Generator Operating Model is selected. In the Electromagnetic tab select Calculate Emagnetic Performance. In the Lab Viewer plot select Drive Cycle and see the operating points of the Drive Cycle on the Efficiency Map.


We can view other Maps via the Tools tab and selecting Saturation and Loss Maps.


Here is a map of phase advance and stator current vs iron loss of the stator. The drop down menus for the three axes can be accessed to change an axis quantity to display a different map.


Calculation inputs can be defined in the Operating Point tab and operating points can be calculated and passed to the Emag physics module for electromagnetic analysis.


The Back EMF and Drag Torque vs Speed curves and be generated via the Calibration tab. Select the Test Type and define the Speed parametric sweep, and then select Calculate Test Performance. 


Open Circuit Test: The Back EMF increases linear with speed while there are two regions for the drag torque. Initially, the change in torque with respect to change of speed is larger in the first region and this rate reduces with speed. It takes less torque to overcome the mechanical torque friction as the motor shaft speeds up due to the inertia of the rotor. 


Short Circuit Test: The stator short circuit current increases with speed since the Back EMF increases with speed, and this short circuit current increases nonlinearly due to the nonlinear inductance of the winding. This short circuit stator current produces a rotating magnetic field that opposes the rotation of the rotor magnetic field and this brakes the rotor to prevent the change of flux in the stator windings.





Ozen Engineering is a leading provider of Ansys solutions, catering to a diverse range of industries with a specialization in electronics, semiconductor, biomedical, healthcare, aerospace and automotive applications. Our team delivers personalized solutions to optimize product design and performance by seamlessly integrating Ansys simulation into the product development process. As an elite channel partner of Ansys, we provide best-in-class software tools, consulting, training, mentoring, and technical support.

Contact us to learn about our simulation capability and request a demonstration for us to show you how we can help you with your engineering projects. Ozen Engineering Inc is an Ansys Elite Channel Partner, and we provide training to use Ansys tools, offer consulting services, and sell Ansys software packages.

Visit our website

Give us a call

(800) 832-3767

Send us a message

Post by David A. Giglio, PhD, PE
May 1, 2024