Grain-oriented electrical steel sheet, manufacturing method therefor, and method for predicting transformer noise property
AssigneeJfe Steel Corporation
InventorsTakeshi OMURA, Hirotaka INOUE, Seiji OKABE
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Abstract
Provided is a grain-oriented electrical steel sheet having an excellent noise property in an actual transformer. Magnetostrictive properties of the grain-oriented electrical steel sheet are set such that the number of acceleration/deceleration points that are present in the magnetostriction velocity level dλ/dt in one period of magnetostrictive vibration is 4 and the magnitude of velocity level change between adjacent velocity change points in an acceleration zone or deceleration zone of magnetostrictive vibration is 3.0×10−4 sec−1 or less.
Claims6
A grain-oriented electrical steel sheet comprising a forsterite film and an insulating coating at a surface thereof, wherein
- magnetostrictive properties of the grain-oriented electrical steel sheet satisfy conditions I and II, shown below,
- I:
- the number of acceleration/deceleration points that are present in a magnetostriction velocity level dλ/dt in one period of magnetostrictive vibration is 4,
- II:
- the magnitude of velocity level change between adjacent magnetostriction velocity level change points in an acceleration zone or deceleration zone of magnetostrictive vibration is 3.0×10−4 sec−1 or less,
- a front/rear difference in total tension of the forsterite film and the insulating coating is less than 0.5 MPa, and
- a front/rear difference in tension of the forsterite film is 0.5 MPa or more.
A method for predicting a transformer noise property, comprising
- predicting a noise property of a transformer in which a grain-oriented electrical steel sheet including a forsterite film and an insulating coating at a surface thereof is used by using a magnetostrictive property III and a magnetostrictive property VI of the transformer, shown below,
- magnetostrictive property III:
- the number of acceleration/deceleration points present in a magnetostriction velocity level dλ/dt in one period of magnetostrictive vibration,
- magnetostrictive property VI:
- the magnitude of velocity level change between adjacent magnetostriction velocity level change points in an acceleration zone or deceleration zone of magnetostrictive vibration.
Dependencies are inferred from the claim text.