Journal of Strain Analysis for Engineering Design, Apr 19, 2021
High-speed electrical machines (HSEMs) are becoming more popular in applications such as air hand... more High-speed electrical machines (HSEMs) are becoming more popular in applications such as air handling devices. Using surface-mounted permanent magnet (PM) rotors manufactured from rare earth metals, they provide benefits over their mechanical transmission counterparts. However, these PMs have low tensile strength and are prone to failure under large centrifugal loads when rotating. Therefore, retaining sleeves are used to hold the PMs in compression to eliminate tensile stress and reduce failure risk. The magnets are also often held on a back iron or carrier, forming an assembly of three cylinders. The ability to predict these stresses is extremely important to rotor design. Current published work shows a lack of exploration of analytical methods of calculating these stresses for three-cylinder assemblies. This paper shows the development of plane stress, plane strain and generalised plane strain (GPS) theories for three cylinders. For a range of rotor designs, these theories are compared with finite element analysis (FEA). GPS is shown to be more accurate than plane stress or plane strain for the central region of long cylinders. For short cylinders and for the ends of cylinders, all three theories give poor results.
High-speed electrical machines (HSEMs) are increasingly used in applications such as air handling... more High-speed electrical machines (HSEMs) are increasingly used in applications such as air handling devices. Using surface-mounted permanent magnet (PM) rotors manufactured from rare earth metals, they provide benefits over their mechanical transmission counterparts. However, these PMs have low tensile strength and are prone to failure under large centrifugal loads when rotating. The ability to predict these stresses is extremely important to rotor design. A novel stress analysis theory for three-cylinder rotors has been developed using generalised plane strain (GPS) theory but remains complex and inefficient to use to manually design rotors. The mechanical optimisation of rotor design has not been widely explored in literature and has not been completed using the GPS theory for three-cylinder rotors. This paper utilises the GPS theory to produce an automatic optimisation tool for the mechanical design of three-cylinder PM rotors.
Journal of Strain Analysis for Engineering Design, Apr 19, 2021
High-speed electrical machines (HSEMs) are becoming more popular in applications such as air hand... more High-speed electrical machines (HSEMs) are becoming more popular in applications such as air handling devices. Using surface-mounted permanent magnet (PM) rotors manufactured from rare earth metals, they provide benefits over their mechanical transmission counterparts. However, these PMs have low tensile strength and are prone to failure under large centrifugal loads when rotating. Therefore, retaining sleeves are used to hold the PMs in compression to eliminate tensile stress and reduce failure risk. The magnets are also often held on a back iron or carrier, forming an assembly of three cylinders. The ability to predict these stresses is extremely important to rotor design. Current published work shows a lack of exploration of analytical methods of calculating these stresses for three-cylinder assemblies. This paper shows the development of plane stress, plane strain and generalised plane strain (GPS) theories for three cylinders. For a range of rotor designs, these theories are compared with finite element analysis (FEA). GPS is shown to be more accurate than plane stress or plane strain for the central region of long cylinders. For short cylinders and for the ends of cylinders, all three theories give poor results.
High-speed electrical machines (HSEMs) are increasingly used in applications such as air handling... more High-speed electrical machines (HSEMs) are increasingly used in applications such as air handling devices. Using surface-mounted permanent magnet (PM) rotors manufactured from rare earth metals, they provide benefits over their mechanical transmission counterparts. However, these PMs have low tensile strength and are prone to failure under large centrifugal loads when rotating. The ability to predict these stresses is extremely important to rotor design. A novel stress analysis theory for three-cylinder rotors has been developed using generalised plane strain (GPS) theory but remains complex and inefficient to use to manually design rotors. The mechanical optimisation of rotor design has not been widely explored in literature and has not been completed using the GPS theory for three-cylinder rotors. This paper utilises the GPS theory to produce an automatic optimisation tool for the mechanical design of three-cylinder PM rotors.
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Papers by Simon Barrans