There is provided a contact type power feeding apparatus in which, even if a brush Br disposed in a space between the axis body and the cylinder body that are disposed concentric with each other wears out as a result of sliding, contact can be surely secured between the brush and the axis body as well as the cylinder body, thereby efficiently causing electric current to flow between the two. A brush Br has first brush pieces each having an inner wall surface to make surface-contact with an outer peripheral surface of the axis body; and second brush pieces each having an outer wall surface to make a surface-contact with an inner peripheral surface of the cylinder body. The brush is constituted by alternately arranging, in the circumferential direction, the first brush pieces and the second brush pieces in a state of keeping them in surface-contact with each other. The side wall surfaces of the first brush pieces and the second brush pieces are respectively formed into a tapered shape which is inclined relative to the radial direction. Coil springs are disposed between the second brush pieces that are adjacent to each other, in order to give a biasing force in a direction to move the second brush pieces away from each other.

In order to effect a seal a porous material which comprises one side of two opposing surfaces is used to restrict and evenly distribute externally pressurized gas, liquid, steam, etc. between the two surfaces, exerting a force which is opposite the forces from pressure differences or springs trying to close the two faces together and so may create a non-contact seal that is more stable and reliable than hydrodynamic seals currently in use. A non-contact bearing is also disclosed having opposing surfaces with relative motion and one surface issuing higher than ambient pressure through a porous restriction, wherein the porous restriction is part of a monolithic porous body, or a porous layer, attached to lands containing a labyrinth, the porous restriction and lands configured to not distort more than 10% of a gap created from differential pressure between each side of the porous restriction.

In order to effect a seal a porous material which comprises one side of two opposing surfaces is used to restrict and evenly distribute externally pressurized gas, liquid, steam, etc. between the two surfaces, exerting a force which is opposite the forces from pressure differences or springs trying to close the two faces together and so may create a non-contact seal that is more stable and reliable than hydrodynamic seals currently in use. A non-contact bearing is also disclosed having opposing surfaces with relative motion and one surface issuing higher than ambient pressure through a porous restriction, wherein the porous restriction is part of a monolithic porous body, or a porous layer, attached to lands containing a labyrinth, the porous restriction and lands configured to not distort more than 10% of a gap created from differential pressure between each side of the porous restriction.

An electric circuit providing a ground connection includes at least two brushes and a contact member, wherein each brush and the contact member form a sliding contact, wherein the contact member is connected to a ground potential by at least one of the sliding contacts, wherein at least two of the sliding contacts are connected to a current source adapted to provide a current through the sliding contacts.

An electric circuit providing a ground connection includes at least two brushes and a contact member, wherein each brush and the contact member form a sliding contact, wherein the contact member is connected to a ground potential by at least one of the sliding contacts, wherein at least two of the sliding contacts are connected to a current source adapted to provide a current through the sliding contacts.

A slip ring apparatus, a yaw system, and a wind turbine generator set are provided. The slip ring apparatus includes a rotating part and a fixed part, the rotating part can rotate relative to the fixed part, a conductive ring is provided on the rotating part, an electric brush is provided on the fixed part, and a chute is formed in at least one of the conductive ring and the electric brush, so that when the conductive ring and the electric brush are in contact, the chute can discharge abrasive dust generated when the conductive ring and the brush are in contact, thereby suppressing the increase of fretting contact resistance between the conductive ring and the electric brush.

A slip ring apparatus, a yaw system, and a wind turbine generator set are provided. The slip ring apparatus includes a rotating part and a fixed part, the rotating part can rotate relative to the fixed part, a conductive ring is provided on the rotating part, an electric brush is provided on the fixed part, and a chute is formed in at least one of the conductive ring and the electric brush, so that when the conductive ring and the electric brush are in contact, the chute can discharge abrasive dust generated when the conductive ring and the brush are in contact, thereby suppressing the increase of fretting contact resistance between the conductive ring and the electric brush.

Provided is an apparatus for treating a substrate including: a processing vessel having a processing space; a support unit for supporting the substrate in the processing space and rotating the substrate; a liquid supply unit for supplying a processing liquid to the substrate; and a heating unit for heating the substrate, wherein the support unit includes: a spin chuck; a rotation driver for rotating the spin chuck; a chuck pin installed on the spin chuck to be rotated with the spin chuck; a chuck pin moving unit for moving the chuck pin between a contact position wherein the chuck pin is in contact with a side portion of the substrate and an open position at which the chuck pin is spaced apart from the side portion of the substrate, and the chuck pin moving unit moves the chuck pin while the substrate is rotated by the spin chuck.

Provided is an apparatus for treating a substrate including: a processing vessel having a processing space; a support unit for supporting the substrate in the processing space and rotating the substrate; a liquid supply unit for supplying a processing liquid to the substrate; and a heating unit for heating the substrate, wherein the support unit includes: a spin chuck; a rotation driver for rotating the spin chuck; a chuck pin installed on the spin chuck to be rotated with the spin chuck; a chuck pin moving unit for moving the chuck pin between a contact position wherein the chuck pin is in contact with a side portion of the substrate and an open position at which the chuck pin is spaced apart from the side portion of the substrate, and the chuck pin moving unit moves the chuck pin while the substrate is rotated by the spin chuck.