# US 2018/0025833 A1 · Stationary induction apparatus

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- Number: US 2018/0025833 A1
- Document ID: US20180025833A1
- Status: Published application
- Kind: A1
- Application number: 15/549,455
- Filed: 2016-02-17
- Published: 2018-01-25
- Earliest claimed: 2015-03-24
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Soichiro KAINAGA; Takahiro UMEMOTO; Takao TSURIMOTO
- Web page: https://patentgrep.com/patent/US20180025833A1

## CPC

- H01F 27/343: {Preventing or reducing surge voltages; oscillations}
- H01F 27/2885: {with shields or electrodes (shields or electrodes for pancake coils H01F27/2871; construction of electric or magnetic shields or screens H01F27/36)}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

A plurality of windings each including an electric wire portion and a first insulating coating that coats the electric wire portion. A plurality of electrostatic shields each including a conductor and a second insulating coating that coats the conductor. A stationary induction apparatus satisfies at least one positional relationship among: a relationship in which an outer peripheral end of the conductor in each of the electrostatic shields is located inside an outer peripheral end of the electric wire portion of an adjacent winding among the windings, the adjacent winding being adjacent to the electrostatic shield in the direction extending along the central axis; and a relationship in which an inner peripheral end of the conductor in each of the electrostatic shields is located outside an inner peripheral end of the electric wire portion of the adjacent winding.

## Claims

### Claim 1

A stationary induction apparatus comprising:
a core;
a plurality of windings wound around the core that is a central axis; and
a plurality of annular electrostatic shields disposed adjacent to respective ends of the plurality of windings in a direction extending along the central axis,
each of the plurality of windings including
an electric wire portion, and
a first insulating coating that coats the electric wire portion,
each of the plurality of electrostatic shields including
a conductor, and
a second insulating coating that coats the conductor,
the stationary induction apparatus satisfying at least one positional relationship among
a positional relationship in which an outer peripheral end of the conductor in each of the plurality of electrostatic shields is located inside an outer peripheral end of the electric wire portion of an adjacent winding among the plurality of windings by a distance of 1% or more and 20% or less of a width of the adjacent winding in a radial direction of the central axis, the adjacent winding being adjacent to the electrostatic shield in the direction extending along the central axis, and
a positional relationship in which an inner peripheral end of the conductor in each of the plurality of electrostatic shields is located outside an inner peripheral end of the electric wire portion of the adjacent winding by the distance of 1% or more and 20% or less of a width of the adjacent winding in the radial direction of the central axis.

### Claim 2 (depends on 1)

The stationary induction apparatus according to claim 1, wherein an electric field generated at the outer peripheral end of the conductor is smaller than an electric field generated at the outer peripheral end of the electric wire portion of the adjacent winding.

### Claim 3

(canceled)

### Claim 4 (depends on 1)

The stationary induction apparatus according to claim 1, wherein an electric field generated at the inner peripheral end of the conductor is smaller than an electric field generated at the inner peripheral end of the electric wire portion of the adjacent winding.

### Claim 5

(canceled)

### Claim 6 (depends on 1)

The stationary induction apparatus according to claim 1, wherein
the conductor includes
an annular base extending in the radial direction of the central axis, and
a pair of extensions individually extended from opposite ends in the radial direction of the central axis of the base,
in each of the pair of extensions, at least a surface opposite to a winding in the direction extending along the central axis is rounded, and
each of the pair of extensions projects opposite to the winding relative to the base in the direction extending along the central axis.

### Claim 7 (depends on 1)

The stationary induction apparatus according to claim 1, wherein the plurality of windings are concentrically wound around the core.

### Claim 8 (depends on 1)

The stationary induction apparatus according to claim 1, wherein the plurality of windings are wound around the core to be coaxially disposed.

### Claim 9 (depends on 1)

The stationary induction apparatus according to claim 1, wherein
the second insulating coating includes
a first insulator disposed on the winding side adjacent to the electrostatic shield, and
a second insulator disposed opposite to the winding adjacent to the electrostatic shield, and
only a surface of the second insulator facing the first insulator is provided with an annular groove corresponding to an outside shape of the conductor.