We are using a test rig to demonstrate an electric motor test with a torque transducer placed between the drive and the brake. With this test rig, we can control torque and speed to look at the different output states to imitate real world scenarios. To further visualize the benefits of the eDrive system, we have mapped the electrical and mechanical output of an e-motor. Watch the video to check out what it looks like in the software!
From torque to electric power testing: in this video we will show you how to maximize the investment of your HBM torque sensor by pairing it with the HBM power analyzer of the eDrive series. Let’s have a look at the hardware.
In the test rig used to demonstrate an electric motor test, we are using a torque transducer which is placed between the drive and the brake. With this test rig, we can control torque and speed to look at the different output states to imitate real world scenarios. The output of the torque and speed sensors are connected to our eDrive power analyzer which time aligns them with the voltage and the current signals.
You also have the option to add other channels to measure temperature or vibration. The power analyzer can be connected to either a PC or a tablet for setup and data analysis in the eDrive software. The system could also be set up using software commands by utilizing our API. The splitter box connects the torque and speed outputs to the power analyzer and provides the possibility to repeat the signals for your automation system.
To further visualize the benefits of the eDrive system, we have mapped the electrical and mechanical output of an e-motor in the software.
The eDrive software is showing a measurement of a three-phase permanent magnet motor. We have current and voltage in red and blue and the torque and speed output from a T12HP in pink and green. The eDrive system can display and record the full bandwidth of the torque sensor and electrical signals. Time alignment of these signals makes for a very simple visualization of the measured parameters allowing users to make decisions quickly. Notice the small torque ripple caused by the motor construction. This shows the high accuracy and bandwidth of the torque measurement.
For events like a load step shown in the middle of the screen, you can closely watch how the electrical system responds to a change in torque. This allows users to understand their motor at a system level. Electrical and mechanical data are averaged on the same time basis for doing power measurements. This ensures that there is no shift between signals again maximizing accuracy. The eDrive system directly measures the frequency output of the torque sensor using high accuracy timer counter channels. The frequency signal can be shown zoomed in at the bottom of the screen.
eDrive can average this frequency on a short time period shown in the middle screen at the full bandwidth. In the bottom screen, the torque averaging period is synchronized with the electrical signals for calculating highly accurate power and efficiency measurements. The ability to record the raw data and average it on unique time frames makes for the highest accuracy measurement, giving you the ability to trust what values you are getting.
So by pairing the eDrive system with your torque sensor you are not only increasing the accuracy of your full measurement chain but you are also enabling more advanced testing capabilities for example time aligning electrical and mechanical signals at their full bandwidth. As a result, you and your team can decrease development time of your e-motor.
Questions? Contact Our Expert Mitchell Marks
Mitchell Marks, business developement manager, is among HBM's many experts in electric machine and drivetrain testing. He has a Masters in electrical engineering and is looking foward to answering any questions regarding our workshop, products or applications.