Method and apparatus for reducing bearing current in a motor and/or generator

• US 20020121821A1
• Filed: 03/02/2001
• Published: 09/05/2002
• Est. Priority Date: 03/02/2001
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Ritter, Allen Michael
• Application Number:
  US09/798,093
• Publication Number:
  US 20020121821A1
• Time in Patent Office: Days
• US Class Current: 310/71
• CPC Class Codes: H02K 11/40 Structural association with grounding devices

Abstract

The present invention enables removal of unwanted shaft currents from motors and/or generators by effectively placing a seal or a bushing in contact with the motor housing and the motor shaft. Many existing motor units can be effectively retrofitted to include these efficient current discharge mechanisms.

Claims

1. An apparatus used in combination with a motor for discharging current, wherein the motor includes a housing at an electrical ground potential and a rotatable motor shaft comprising induced currents, the apparatus comprising:

a bushing in electrical contact with both and an the housing and the shaft, the bushing further comprising;

a first part made of conductive material in electrical contact with the shaft;

a second part made of conductive material in electrical contact with the housing; and

a conductive material at an interface between the first part and the second part; and

a bracket connected to the housing.

2. The apparatus of claim 1, wherein the conductive material is electrically conductive grease.

3. The apparatus of claim 1, wherein the induced currents of the rotatable motor shaft are discharged to the housing at the electrical ground potential through the bushing.

4. The apparatus of claim 1, wherein the bracket is removable.

5. The apparatus of claim 1, wherein the bushing is removable.

6. The apparatus of claim 1, wherein the bushing is placed onto the rotatable motor shaft of the motor.

7. The apparatus of claim 1, wherein the bushing is employed retrofitted on an existing motor.

8. A method for installing a current discharge device on a motor, wherein the motor includes a housing at an electrical ground potential and a rotatable motor shaft comprising induced currents, the method comprising the steps of:

removing a bracket located on the motor;

placing a completely electrically conductive bushing into the motor so that a first part of the bushing is in electrical contact with the motor shaft and a second part of the bushing is in electrical contact with a motor housing; and

rotating the rotatable motor shaft to remove any induced currents from the motor shaft.

9. An apparatus used in combination with a motor for discharging current, wherein the motor includes a housing at an electrical ground potential and a rotatable motor shaft comprising induced currents, the retrofit apparatus comprising:

a seal in electrical contact with both and an the housing and the shaft, the seal further comprising;

a first part made of conductive material in direct contact with the shaft; and

a second part made of conductive material in direct contact with the housing;

wherein said first part creates a seal completely around the circumference of the shaft; and

a bracket connected to the housing.

10. The apparatus of claim 9, wherein the induced currents of the rotatable motor shaft are discharged to the housing at the electrical ground potential through the seal.

11. The apparatus of claim 9, wherein the bracket is removable.

12. The apparatus of claim 9, wherein the seal is removable.

13. The apparatus of claim 9, wherein the bushing is placed onto the rotatable motor shaft of the motor.

14. The apparatus of claim 9, wherein the bushing is employed retrofitted on an existing motor.

15. A method for installing a current discharge device on a motor, the motor includes a housing at an electrical ground potential and a rotatable motor shaft comprising induced currents, the method comprising the steps of:

removing a bracket located on the motor;

placing a completely electrically conductive bushing into the motor so that a first part of the bushing is in electrical contact with the motor shaft and a second part of the bushing is in electrical contact with a motor housing; and

rotating the rotatable motor shaft to remove any induced currents from the motor shaft.