Amorphous metal core transformer

• US 6,750,749 B2
• Filed: 07/30/1999
• Issued: 06/15/2004
• Est. Priority Date: 07/31/1998
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shirahata, Toshiki, Inagaki, Katsutoshi, Urata, Shinya, Horiuchi, Masayuki
• Primary Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US09/363,836
• Publication Number:
  US 20020057180A1
• Time in Patent Office: 1,782 Days
• Field of Search: 336/212, 336/210, 336/213, 336/216, 336/234, 336/223, 336/57, 336/58, 336/61, 336/69, 336/55, 336/180-185, 336/220, 336/221, 336/198
• US Class Current: 336/55
• CPC Class Codes: H01F 30/12 Two-phase, three-phase or polyphase transformers

Abstract

An amorphous metal core transformer is provided with a plurality of wound magnetic cores composed of amorphous metal strips, and a plurality of coils, each of the coils including a primary coil and a secondary coil, each of the coils further including a bobbin. The primary coil employs different material from that of the secondary coil, e.g., a copper conductor is employed in a primary coil, while an aluminum conductor is employed in a secondary coil. The bobbin has higher strength than that of the amorphous metal strips.

Claims

1. An amorphous metal core transformer, comprising:

a magnetic core composed of a plurality of amorphous metal strips;

a bobbin disposed around said magnetic core, said bobbin being made of a material having a greater strength than that of a material of said amorphous metal strips;

a primary coil of a copper conductor material wound on said magnetic core; and

a secondary coil of an aluminum conductor material wound on said primary coil and disposed outside said primary coil in a radius direction of said primary coil, wherein

a calorific value generated by a current flowing through said primary coil is greater than calorific value generated by a current flowing through said secondary coil, so that the heat generated from the primary coil is dissipated in said magnetic core to suppress temperature rise of said primary coil, and

said material of said bobbin is made of steel.

2. An amorphous metal core transformer comprising:

a magnetic core composed of a plurality of amorphous metal strips;

a primary coil wound on said magnetic core, said primary coil being composed of copper conductor winding; and

a secondary coil wound on said primary coil and disposed outside said primary coil in the radius direction of said primary coil, said secondary coil being composed of aluminum conductor winding, wherein

a value of current density of said primary coil is greater than a value of current density of said secondary coil, wherein said value of current density of said primary coil is indicated in terms of current density of the aluminum conductor winding, and

a calorific value generated by a current flowing through said primary coil is greater than a calorific value generated by a current flowing through said secondary coil, so that the heat generated from the primary coil is dissipated in said magnetic core to suppress temperature rise of said primary coil.

3. An amorphous metal core transformer according to claim 2, wherein,

said secondary coil has a greater length than the primary coil in the axial direction thereof.

4. An amorphous metal core transformer according to claim 2, wherein,

said primary coil employs a rectangular copper wire, and said secondary coil employs an aluminum strip.

5. An amorphous metal core transformer according to one of claim 2, further comprising a casing for containing said magnetic cores and said coils, said casing being filled with an insulative cooling medium, said casing having cooling fins formed so as to project from a surface of said casing, wherein,

said cooling fins project from said surface of said casing from 17 mm to 280 mm in height, and the total surface area of said cooling fins and said casing is 130 m2 or less.

6. An amorphous metal core transformer according to claim 2, wherein

four pieces of said wound magnetic cores and three pieces of coils are assembled so as to compose a three phase transformer having five-legged magnetic cores.

7. An amorphous metal core transformer according to claim 6, wherein,

said three phase transformer has a capacity of 750 kVA or more and said three coils are connected in Δ

-Δ

connection system.