The Importance and Complexity of Testing Your Electric Motor's Stator

stator and rotor stack

Securing the reliability, efficiency, and performance of electric vehicles (EV) or electric aircraft requires a deep dive into the heart of their motors  — the stator. At Carpenter Electrification, we prioritize meticulous stator testing, examining each component down to the finished stack level to guarantee the premium quality of our products.

What is the Role of a Stator in an Electric Motor?

The stator, a stationary component in the electric motor, plays a pivotal role in generating the magnetic field that propels the rotor, creating the torque and power that drive the motor. 

Its design, material, and structural integrity are critical in determining the motor's performance, influencing efficiency, power output, and overall reliability. Thus, ensuring the stator is of optimal quality is paramount, making its testing a vital step in manufacturing.

What Are the Key Components of Stator Testing?

While the industry has conventionally leaned towards ring testing, a method that tests material at a lamination level, it does not scrutinize the actual parts shipped to customers — most importantly, the stator. Our innovative approach at Carpenter Electrification ensures:

Quality Assurance: A transparent, in-depth look into the quality of each part.

Precision: We provided the most accurate assessment of stator and rotor magnetic performance. Our testing approach accounts for the impact of part geometry and stack processing to provide a comprehensive view of the performance within the motor.

Production Consistency: A guarantee that every part, from the first to the last, is consistent in quality and performance.

What Makes Stator Testing Complex or Challenging?

The complexity of stator testing is deeply intertwined with motor design. Each design demands a unique testing "recipe," which can vary significantly, making the process multifaceted and complex. The challenges are further compounded when dealing with various stator sizes and designs and the complexity of analyzing and translating the data into actionable insights for customers. Moreover, converting the data into a format that aligns with what motor designers need adds another layer of complexity, ensuring the data is accurate but also relevant and applicable.

How to Test Your Stator

Stator testing, while seemingly straightforward, involves a meticulous process to ensure that every aspect is thoroughly examined, providing a comprehensive view of its quality and performance. At Carpenter Electrification, the testing process is crafted to scrutinize various parts of the stator, ensuring that the data derived is accurate and valuable in assessing and ensuring quality. Here's a glimpse into stator testing:


  • Material selection: Ensure the stator is made from materials that meet the design specifications.
  • Visual inspection: Conduct a preliminary visual inspection to identify defects or issues.
  • Pre-testing calibration: Calibrate testing equipment for accurate results.

Testing Setup Configuration:

  • Selecting the appropriate setup: The appropriate testing setup depends on whether the testing is for a round stator or involves testing each portion.
  • Adjusting parameters: Configure the testing parameters based on the stator's size and dimensions.

Conducting the Tests:

  • Magnetic response testing: Measure magnetic responses, such as B versus H or core losses, at various frequencies and inductions.
  • Testing at multiple points: For B versus H testing, conduct tests at multiple points (e.g., 20, 30, 50, or even 100 test points) to ensure comprehensive data collection.
  • Core loss measurements: Test at various frequencies or inductions, ensuring a thorough examination of core losses.

Data Analysis and Conversion:

  • Analyzing magnetic responses: Evaluate the magnetic responses and core losses to assess the stator's performance.
  • Data conversion: Convert the raw data into a meaningful and applicable format for motor designers, ensuring it provides valuable insights into the stator's performance and quality.

Quality Assessment:

  • Comparing data against benchmarks: Evaluate the data against established benchmarks to ensure the stator meets the requisite performance and quality standards.
  • Identifying and addressing issues: Should any issues or deviations be identified, investigate and address them to ensure quality and consistency.

Customer Communication:

  • Translating data into insights: Ensure that the data is communicated to customers in a way that provides clear insights into the stator's quality and performance.
  • Providing comprehensive reports: Offer detailed reports that share the data and provide insights and explanations, ensuring customers can make informed decisions.

Through this meticulous testing process, reliable and efficient stators  for electric motors are ensured. 

The Implications of Stator Testing for Manufacturers and Users

Ensuring the stator is thoroughly tested is critical to preemptively identifying and mitigating potential failures, thereby safeguarding and enhancing motor performance. A failure in the stator could lead to overheating or a complete halt of the motor, which could have serious implications, especially in critical applications like electric vertical takeoff and landing (eVTOL) aircraft. In such applications, engines are often over-designed to allow for a certain level of failure while still maintaining operability, ensuring both reliability and the safety of the vehicle and its occupants.

The Final Say on Stator Testing 

Carpenter Electrification is committed to propelling the future of electric motors by ensuring every stator meets and exceeds quality and performance expectations. Through our rigorous testing processes, we provide components that are not just fit for use but are exemplary in their performance, ensuring customers receive products that stand the test of time and drive innovation.

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