Iron core for transformer
AssigneeJfe Steel Corporation
InventorsTakeshi Omura, Hirotaka Inoue, Seiji Okabe
Life of this patent
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Abstract
Vibration of an iron core is reduced to reduce transformer noise. An iron core for a transformer comprises a plurality of grain-oriented electrical steel sheets stacked together, wherein at least one of the plurality of grain-oriented electrical steel sheets: (1) has a region in which closure domains are formed in a direction crossing a rolling direction and a region in which no closure domains are formed; (2) has an area ratio R0 of 0.10% to 3.0%, the area ratio R0 being defined as a ratio of S0 to S; and (3) has an area ratio R1a of 50% or more, the area ratio R1a being defined as a ratio of S1a to S1.
Claims4
An iron core for a transformer, comprising
- a plurality of grain-oriented electrical steel sheets stacked together,
- wherein at least one of the plurality of grain-oriented electrical steel sheets:
- (1) has a region in which closure domains are formed in a direction crossing a rolling direction and a region in which no closure domains are formed;
- (2) has an area ratio R0 of 0.10% to 3.0%, the area ratio R0 being defined as a ratio of S0 to S;
- and
- (3) has an area ratio R1a of 50% or more, the area ratio R1a being defined as a ratio of S1a to S1,
- where S is an area of the grain-oriented electrical steel sheet, S1 is an area of the region in which the closure domains are formed, S0 is an area of the region in which no closure domains are formed, and S1a is, in the region in which the closure domains are formed, an area of a region in which an expansion amount at a maximum displacement point when excited in the rolling direction at a maximum magnetic flux density of 1.7 T and a frequency of 50 Hz is at least 2×10−7 greater than an expansion amount in the region in which no closure domains are formed.
Dependencies are inferred from the claim text.