Customer Reviews
Application example of Torque Detector RH series
Custom Motor Bench for Investigating and Minimizing Iron Loss
The Graduate School of Frontier Sciences, The University of Tokyo
Customer Reviews
The Graduate School of Frontier Sciences, The University of Tokyo
Creating New Academic Fields by Transdisciplinary Approaches
The Graduate School of Frontier Sciences (GSFS) was established in 1998 to create new academic fields based on a concept, which we call gakuyugo (transdisciplinary approaches). Supported by all graduate schools of the University of Tokyo, an independent graduate school was launched exclusively for master's and doctoral courses. Approximately 200 faculty members and 1,600 graduate students are enrolled.
This time, we interviewed researchers at the University of Tokyo's Kashiwa Campus.
The University of Tokyo Graduate School of Frontier Sciences Website
Challenges
Minimizing Iron Losses: Addressing the Inherent Challenge in Motor Design
Kaiki Akizuki, doctoral student in the Department of Advanced Energy at the GSFS, University of Tokyo, is conducting research to minimize "iron loss," a type of loss generated by motors.
"Three-phase AC motors are widely used in industrial equipment and have an established image. Iron loss is one type of loss that must be considered in order to achieve even higher efficiency, since it is difficult to measure directly, the detailed mechanism was not understood. Even if iron loss could be reduced, it would have to be tolerated because of the unknown mechanism. Therefore, there are few papers that actually mention this."
If we can figure out how iron loss works and control it properly, even a tiny improvement in efficiency can have a huge impact on the world.
"It is generally known that motors cannot produce a clean sine wave current under normal control conditions due to spatial harmonics. However, we have confirmed that controlling and suppressing these spatial harmonics produces a sine wave current and reduces iron loss."
Custom motor bench assembled by our company (left photo) and motor for iron loss research prototyped by Daikin Industries, Ltd. (right photo)
In Akizuki's research, grooves are carved into the stator of a three-phase AC motor, coils are inserted into the grooves, and iron loss generated in the electromagnetic steel plate is confirmed. The magnetic phenomena are dynamically monitored and evaluated.
"Of the uvw low-voltage side windings of a three-phase AC motor, testing is difficult for all three phases, so we are testing only one phase. We are considering researching all three phases in the future."
Doctoral Programme in the Department of Advanced Energy, Kaiki Akizuki
Results
A High-Precision and Responsiveness Torque System for Advanced Motor Research
To accurately measure this iron loss, Ono Sokki has had repeated discussions with the customer regarding the specifications and delivered a custom-made motor bench that combines the compact & high rigidity type torque detector, RH series with a control motor.
We asked Dr. Toshiyuki Fujita, the Project Lecturer why he chose our product.
We introduced it in 2022. After comparing several companies, including yours, we considered after-sales service and performance and decided on your custom motor bench. The precision and responsiveness are excellent.
Department of Advanced Energy, Project Lecturer, Dr. Toshiyuki Fujita
Akizuki, who uses this product day and night, says,
"We normally use this to evaluate main iron loss. The maximum torque is about 1.5 N·m. The maximum rotation speed is about 6000 r/min. We are currently measuring at about 3000 r/min. The higher the measurement accuracy, the better. We also evaluate power by connecting it to a power meter."
Customer reviews
Even on a global scale, researchers focusing on iron loss are rare, however, Akizuki's challenge continues.
"Compared to general control, we performed control that approximates a sine wave as closely as possible and compared the effects of iron loss reduction. This was confirmed by both the power meter and direct measurements using the model I use. Recently, we have been conducting research based on the hypothesis that the peak portion of the current may affect iron loss."
What’s next?
"We would also like to check torque ripple. For example, even if we want to implement a certain control to reduce iron loss, there is a possibility that it will cause torque ripple. We would like to evaluate that," said Akizuki.
If we can fully elucidate the mechanism of iron loss and improve motor efficiency, the contribution to a sustainable society will be tremendous. We will continue to support researchers who take on unprecedented challenges and assist them in their endeavors.
Products for solutions
This measurement system combines the MT series Torque Detector, which can be used with a wide variety of motors, with the TS series Torque Station.
It enables highly accurate and responsive torque measurement with a maximum sampling rate of 5.12 kHz and accuracy of ±0.1% FS.
We contribute to solving customer problems in a wide range of fields, including automobiles, home appliances, mobility, power generation, and medical care.
Torque Detector MT series
Last update : 2025/07/30