Magtrol project team.

Fractional horsepower motors are ubiquitous – fueling power tools, permitting the opening and closing of car windows, and spinning the blades of a blender, to name a few applications. For a motor to attain an energy efficient label, certain torque and speed qualifications are required. How do you determine conformance? By testing with a dynamometer, like those manufactured by world leader Magtrol Inc., which has headquarters in Buffalo, N.Y., and plants in Switzerland and Shanghai.

About 40 percent of Magtrol’s business is in Europe and Asia, from companies that have largely adopted stricter motor test industry regulations over the past year. A revised European Union standard, in particular, increases the accuracy requirements for torque measurements.    

Magtrol leaders contend that several motor test companies claiming spec compliancy don’t have the math to support it. “We don’t think that’s acceptable,” says General Manager Tom Rymarczyk. So, to uphold their own company’s reputation and globally recognized quality, they insist on evidence. Magtrol engineers focused on their best-selling hysteresis dynamometer to empirically determine it is aligned with the accuracy class. But limited knowledge of statistical analysis stopped them short of mathematically verifying it. They turned to UB’s engineering faculty to weed through variables and provide proof of compliance.

The Approach

After a team of Magtrol engineers dissected current dynamometer accuracy with a mathematical model, a UB Department of Mechanical and Aerospace Engineering assistant professor and two graduate engineering students stepped in to:

  • Analyze Magtrol’s sensitivity analysis
  • Conduct an additional sensitivity and uncertainty study by leveraging MATLAB software to harness global sensitivity analysis
  • Identify and prioritize variables – such as local gravity or temperature – that have the greatest impact on accuracy 
  • Determine a new equation, improving accuracy, for the dynamometer’s calibration process
  • Devise a calibration system that incorporates automation

The Impact

  • Formulated a precise, mathematical-based method for analyzing accuracy that’s applicable to the design or evaluation of all torque-measuring devices
  • Heightened reliable data collection
  • Provided inputs for Magtrol engineers to construct a more sophisticated dynamometer calibration machine – thereby enabling future diversification with a premium product – which will feature:
    • A rigorous calibration process
    • Automated components to eliminate human error and inconsistencies
  • Elevated marketing with validation of the hysteresis dynamometer’s 0.2 class, per International Electrotechnical Commission (IEC) standards