Apparatus and method for suspending a stator core of an electric generator

• US 20040000819A1
• Filed: 03/26/2003
• Published: 01/01/2004
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Alstom Technology Ltd. (Alstom SA)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Jonson, Leif
• Granted Patent: US 7,045,918 B2
• Time in Patent Office: Days
• US Class Current: 310/51
• CPC Class Codes: H02K 1/185 to outer stators

Abstract

An apparatus and method for suspending a stator core (100) in an electric generator upon a foundation (206), where two natural modes of vibration, including known second and third modes, are excited in the core, each mode having four loops and four nodes displaced 45 degrees between the second and third modes. A non-rigid connection (212) connects a yoke to the foundation, and two connection members connect the yoke to the stator core at opposite sides of the non-rigid connection. The two connection points (210a,b) are located at adjacent loops of one of the second and third vibration modes. By this arrangement, radial deflections of the stator core at the respective connection points are transferred into a rocking movement of the yoke around the non-rigid connection. Thereby, vibrations transferred to the foundation are considerably reduced during operation.

Claims

1. A suspension apparatus for suspending a ring-shaped or tube-shaped stator core (100) in an electric generator upon a foundation (206), wherein natural modes of vibration are excited in the stator core during operation, including a known second vibration mode with four circumferentially distributed loops (L1) and four nodes (N1) being displaced 45 degrees from the loops (L1), and a known third vibration mode with four loops (L2) and four nodes (N2) displaced 45 degrees in relation to the loops (L1) and nodes (N1) of the second vibration mode, characterised by:

a yoke (208),

a non-rigid connection (212) connecting the yoke and the foundation, and

two connection members connecting the yoke and the stator core at connection points (210a,b) on opposite sides of the non-rigid connection (212),

wherein the connection points (210a,b) are located on the stator core substantially at two adjacent loops of one of the second and third vibration modes, such that radial deflections of the stator core at the respective connection points are transferred into a rocking movement of the yoke (208) around the non-rigid connection (212).

2. A suspension apparatus according to claim 1, characterised in that at least one of the connection members between the yoke and the stator core comprises a resilient connection.

3. A suspension apparatus according to claim 1 or 2, characterised in that two yokes (400ab,bc) are pivotally connected to the foundation at opposite sides of the stator core, each yoke being connected to the stator core at an upper (402a,c) and a lower (402b) connection point.

4. A suspension apparatus according to claim 3, characterised in that the lower connection points (402b) of the two yokes coincide circumferentially.

5. A suspension apparatus according to any of claims 1-4, characterised in that each connection member between the yoke and the stator core includes a beam (302) extending axially between two flanges or lugs (300) on the stator core.

6. A suspension apparatus according to claim 5, characterised in that the beam (302) is resilient for absorbing sudden shock pulses of the stator core in a tangential direction.

7. A method of suspending a ring-shaped or tube-shaped stator core (100) in an electric generator upon a foundation (206), wherein natural modes of vibration are excited in the stator core during operation, including a known second vibration mode with four circumferentially distributed loops (L1) and four nodes (N1) being displaced 45 degrees from the loops (L1), and a known third vibration mode with four loops (L2) and four nodes (N2) displaced 45 degrees in relation to the loops (L1) and nodes (N1) of the second vibration mode, characterised by the steps of:

connecting a yoke (208) to the foundation (206) by means of a non-rigid connection (212), and

connecting the yoke to the stator core at connection points (210a,b) on opposite sides of the non-rigid connection (212) by means of two connection members, wherein the two connection points (210a,b) are located on the stator core substantially at two adjacent loops of one of the second and third vibration modes, such that radial deflections of the stator core at the respective connection points are transferred into a rocking movement of the yoke (208) around the non-rigid connection (212).