Magnetics Business & Technology - May/June 2023 - 28

CASE STUDY
How to Save Time when Developing an Axial-Flux Motor
magnetic field scanning camera and the advanced data analysis
features of MagScope, Magcam's measurement and analysis
software.
Example of an axial-flux motor design by YASA
A leading electric motor design company integrates Magcam's
Axial Flux Rotor Scanner in a high-performance motor production
line.
Permanent magnet axial-flux motors are increasingly used in
hybrid and pure electric powertrains in the automotive, aviation
and electric bike industry. With short path axial-flux rotors, the
direction of the magnetic flux is aligned parallel with the axis of
rotation which allows the production of lighter and shorter motors
with high torque density.
This case study presents a recent project with a leading electric
vehicle motor development and manufacturing company. The
company involved specializes in making permanent magnet
axial-flux motors.
Reliability is paramount in the automotive industry. Automotive
OEMs want evidence of the reliability and robustness of axial-flux
motors for mass manufacturing, and this has been a challenge.
This has led axial-flux motor suppliers to carry out their own
extensive validation programs, in order to demonstrate that the
reliability of their motors is equal to that of traditional radial flux
types.
In this project, various versions of axial-flux rotors with different
diameters and layouts had to be evaluated. A strong focus lies
on the magnetic characteristics such as magnetic field distribution,
field homogeneity of the different zones, zero crossings
analysis, etc. In addition, the precision of the magnet positioning
had to be inspected by using the magnetic field information of the
invisible encapsulated magnets.
Additional objectives were speeding up development for new designs
and improving production yields in cutting-edge axial-flux
motor production technology.
Magcam's magnetic field scanners are designed for a fast and
accurate quality inspection of permanent magnets and assemblies
such as radial- and axial-flux rotors. These measurement
systems can be integrated into semi or fully automated production
lines.
Unexpected and hard-to-simulate magnet quality issues can be
identified efficiently thanks to the unique combination of a fast
28 Magnetics Business & Technology * May/June 2023
Three-component measurement results of an axial-flux rotor (radial,
tangential, axial) with analysis of magnetic field distributions with
Magcam's MagScope software
The axial-flux rotor scanning method is available for Magcam's
Combi Scanner and Rotor Scanner configurations and benefit
from all well-known Magcam features such as high radial and
angular resolutions, integrated laser surface measurements for
mechanical verification or runout correction measurements, fast
cycle times and in-line advanced data analysis.
Inspecting the magnetic field distribution of an axial-flux rotor with
the MiniCube3D sensor with 0.1mm radial resolution and 0.1° angular
resolution.
One major challenge with axial machines is maintaining a uniform
air gap between the rotor and the stator, as the magnetic
forces are much higher than in radial machines. To obtain the
most precise results, Magcam has developed an automated
runout correction procedure using the integrated laser.
The measurement time depends on the selected angular and
radial resolutions. Typical values are in the range between 1.0°
and 0.1° for the angular resolution and radial resolutions down to
0.1mm are possible using the integrated Magcam MiniCube3D
magnetic field camera.
www.MagneticsMag.com
http://www.MagneticsMag.com
Magnetics Business & Technology - May/June 2023

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