Mechanical reliability of ferrite cores in inductive components

M.J.M. Graaf, de, E. Beck, L.J.M.G. Dortmans

Research output: Contribution to journal › Article › Academic

Abstract

t is a widespread practice to glue mated soft ferrite core halves in the manufacture of inductive components. However, thermally-induced stresses can initiate fracture of the ferrite core in such an inductive component, e.g., a transformer in a switchmode power supply. Therefore, it is essential for designers to know the magnitude of these stresses compared with the strength of the ferrite material. These thermally-induced stresses can originate from and/or be enhanced by: the conditions for gluing of the mated core halves; thermal cycling tests; and trends to a higher power throughput, leading to a higher working temperature (100-1250 degrees C). The magnitude of thermal stresses has been studied for some relevant cases. Absolute stress levels as well as the location of the most critically stressed parts have been identified. In addition, methods for testing the strength of a core half have been analyzed. These analyses are used for a discussion of the relevance of various testing methods to assess the mechanical reliability of ferrite cores in inductive components. The simulations show that mechanical stresses induced by temperature cycling tests of glued ferrite core halves can be very well predicted.
Original languageEnglish
Pages (from-to)59-65
JournalPowerconversion and Intelligent Motion
Volume20
Issue number7
Publication statusPublished - 1994

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Ferrite
Gluing
Glues
Testing
Thermal cycling
Thermal stress
Throughput
Temperature

Cite this

Graaf, de, M. J. M., Beck, E., & Dortmans, L. J. M. G. (1994). Mechanical reliability of ferrite cores in inductive components. Powerconversion and Intelligent Motion, 20(7), 59-65.
Graaf, de, M.J.M. ; Beck, E. ; Dortmans, L.J.M.G. / Mechanical reliability of ferrite cores in inductive components. In: Powerconversion and Intelligent Motion. 1994 ; Vol. 20, No. 7. pp. 59-65.
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abstract = "t is a widespread practice to glue mated soft ferrite core halves in the manufacture of inductive components. However, thermally-induced stresses can initiate fracture of the ferrite core in such an inductive component, e.g., a transformer in a switchmode power supply. Therefore, it is essential for designers to know the magnitude of these stresses compared with the strength of the ferrite material. These thermally-induced stresses can originate from and/or be enhanced by: the conditions for gluing of the mated core halves; thermal cycling tests; and trends to a higher power throughput, leading to a higher working temperature (100-1250 degrees C). The magnitude of thermal stresses has been studied for some relevant cases. Absolute stress levels as well as the location of the most critically stressed parts have been identified. In addition, methods for testing the strength of a core half have been analyzed. These analyses are used for a discussion of the relevance of various testing methods to assess the mechanical reliability of ferrite cores in inductive components. The simulations show that mechanical stresses induced by temperature cycling tests of glued ferrite core halves can be very well predicted.",
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Graaf, de, MJM, Beck, E & Dortmans, LJMG 1994, 'Mechanical reliability of ferrite cores in inductive components', Powerconversion and Intelligent Motion, vol. 20, no. 7, pp. 59-65.

Mechanical reliability of ferrite cores in inductive components. / Graaf, de, M.J.M.; Beck, E.; Dortmans, L.J.M.G.

In: Powerconversion and Intelligent Motion, Vol. 20, No. 7, 1994, p. 59-65.

Research output: Contribution to journal › Article › Academic

TY - JOUR

T1 - Mechanical reliability of ferrite cores in inductive components

AU - Graaf, de, M.J.M.

AU - Beck, E.

AU - Dortmans, L.J.M.G.

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N2 - t is a widespread practice to glue mated soft ferrite core halves in the manufacture of inductive components. However, thermally-induced stresses can initiate fracture of the ferrite core in such an inductive component, e.g., a transformer in a switchmode power supply. Therefore, it is essential for designers to know the magnitude of these stresses compared with the strength of the ferrite material. These thermally-induced stresses can originate from and/or be enhanced by: the conditions for gluing of the mated core halves; thermal cycling tests; and trends to a higher power throughput, leading to a higher working temperature (100-1250 degrees C). The magnitude of thermal stresses has been studied for some relevant cases. Absolute stress levels as well as the location of the most critically stressed parts have been identified. In addition, methods for testing the strength of a core half have been analyzed. These analyses are used for a discussion of the relevance of various testing methods to assess the mechanical reliability of ferrite cores in inductive components. The simulations show that mechanical stresses induced by temperature cycling tests of glued ferrite core halves can be very well predicted.

AB - t is a widespread practice to glue mated soft ferrite core halves in the manufacture of inductive components. However, thermally-induced stresses can initiate fracture of the ferrite core in such an inductive component, e.g., a transformer in a switchmode power supply. Therefore, it is essential for designers to know the magnitude of these stresses compared with the strength of the ferrite material. These thermally-induced stresses can originate from and/or be enhanced by: the conditions for gluing of the mated core halves; thermal cycling tests; and trends to a higher power throughput, leading to a higher working temperature (100-1250 degrees C). The magnitude of thermal stresses has been studied for some relevant cases. Absolute stress levels as well as the location of the most critically stressed parts have been identified. In addition, methods for testing the strength of a core half have been analyzed. These analyses are used for a discussion of the relevance of various testing methods to assess the mechanical reliability of ferrite cores in inductive components. The simulations show that mechanical stresses induced by temperature cycling tests of glued ferrite core halves can be very well predicted.

M3 - Article

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JO - Powerconversion and Intelligent Motion

JF - Powerconversion and Intelligent Motion

SN - 0885-0259

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Graaf, de MJM, Beck E, Dortmans LJMG. Mechanical reliability of ferrite cores in inductive components. Powerconversion and Intelligent Motion. 1994;20(7):59-65.