Effect of Manufacturing Influences on Magnetic Performance Parameters of Sub-Fractional Horsepower Motors

Stefan Leitner*, Hannes Grübler, Annette Muetze

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Depending on the stator lamination manufacturing processes (e.g., punching, laser cutting, clamping, welding, interlocking, and bonding), the motor's magnetic performance parameters, such as cogging torque, hysteresis torque, and iron losses, can vary significantly. In sub-fractional horsepower (SFHP) permanent magnet motors, the manufacturing influence is typically even more severe because, due to their small dimensions, practically, the whole stator material is likely to be affected. This article analyzes the magnetic performance parameters cogging torque, hysteresis torque, and iron losses of three different stator lamination stacks (i.e., M250-35A punched with interlocking, M250-35A laser cut with bonding, and NO10 laser cut with bonding) of an SFHP single-phase brushless permanent magnet motor often found in automotive fan applications. A rheometer is used for extremely accurate torque measurements in the sub-millinewton meter range, and electron backscatter diffraction measurements are performed to visualize changes in the grain morphology and crystal orientation. The findings reveal that the punched stator with interlocking is affected the most by the manufacturing process, showing the lowest cogging torque yet the highest average hysteresis torque and thus up to 40% higher iron losses. The results presented in this article allow for both making basic stator lamination design choices and translating the iron losses, as well as the hysteresis torque and cogging torque waveforms, of a laser cut and bonded prototype into those of its punched and interlocked mass-produced counterpart.

Original languageEnglish
Number of pages10
JournalIEEE Transactions on Magnetics
Issue number12
Publication statusPublished - 1 Dec 2021


  • Bonding
  • brushless motors
  • cogging torque
  • electron backscatter diffraction
  • Forging
  • grain
  • hysteresis torque
  • interlocking
  • iron loss measurement
  • Lamination
  • lamination stack
  • Laser beam cutting
  • laser cutting
  • Magnetic hysteresis
  • manufacturing influences
  • Permanent magnet motors
  • punching
  • rheometer
  • sub-fractional horsepower
  • Torque
  • Torque measurement
  • electron backscatter diffraction (EBSD)
  • sub-fractional horsepower (SFHP)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Fields of Expertise

  • Sustainable Systems
  • Mobility & Production


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