Bus bar system

• US 7,759,577 B1
• Filed: 12/14/2007
• Issued: 07/20/2010
• Est. Priority Date: 07/31/2007
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Morales, Osvaldo P.
• Primary Examiner(s): PATEL, DHIRUBHAI R
• Application Number:
  US11/956,854
• Time in Patent Office: 949 Days
• Field of Search: 174/70.B, 174/71.B, 174/72.B, 174/88.B, 174/99.B, 174/133.B, 174/68.2, 439/210, 439/212, 361/664
• US Class Current: 174/68.2
• CPC Class Codes: H02G 5/002 Joints between bus-bars for compensating thermal expansion

Abstract

A system includes two or more bus bars. One or more fasteners couple at least two adjoining bus bars at a slotted joint. The one or more fasteners hold the adjoining bus bars in contact with one another to enable current to pass from one of the adjoining bus bars to another of the adjoining bus bars through the contacting surfaces of the adjoining bus bars. The slotted joint reduces mechanical stress on at least one of the bus bars when the system is under at least one electrical load condition.

Claims

1. A system, comprising:

a first bus bar comprising one or more slots;

a second bus bar; and

one or more fasteners, at least one of the fasteners being coupled with the second bus bar to couple the first bus bar to the second bus bar, a portion each of the one or more fasteners extending through one of the slots in the first bus bar, each of the one or more fasteners configured to move along at least a portion of a respective slot of the one or more slots to allow relative movement between the first bus bar and the second bus bar along the respective slot under at least one electrical load condition, wherein at least one of the one or more fasteners is preloaded to a predetermined range to maintain electrical connectivity between the first bus bar and the second bus bar while still allowing said relative movement to provide mechanical stress relief under the at least one electrical load condition.

2. The system of claim 1, wherein at least one of the fasteners is a threaded fastener, wherein the second bus bar comprises a threaded hole configured to receive the threaded fastener.

3. The system of claim 1, wherein at least one of the fasteners is a threaded fastener, wherein at least one of the threaded fasteners is preloaded to the predetermined range.

4. The system of claim 1, wherein at least one of the fasteners is a threaded fastener, wherein, under the at least one electrical load condition of the system, at least one of the fasteners is configured to slide along one of the slots and the second bus bar is configured to move relative to the first bus bar.

5. The system of claim 1, wherein the at least one fastener comprises two or more fasteners, wherein the first bus bar comprises one of the slots for each of the fasteners, wherein each of the fasteners couples to the second bus bar through one of the slots in the first bus bar.

6. The system of claim 1, wherein the first bus bar further comprises a longitudinal axis, wherein the one or more slots comprise a longitudinal axis, wherein the longitudinal axes of the one or more slots are substantially parallel to the longitudinal axis of the first bus bar.

7. The system of claim 1, further comprising a third bus bar, wherein the second bus bar is coupled on one side of the first bus bar and the third bus bar is coupled on the other side of the first bus bar.

8. The system of claim 7, wherein the third bus bar is configured to receive one or more additional fasteners, wherein at least one of the additional fasteners couples to the third bus bar to couple the first bus bar to the third bus bar, a portion of each additional fastener extending through one of the slots in the first bus bar, the at least one additional fastener configured to move along at least a portion of the one of the slots to allow said relative movement between the first bus bar and the third bus bar along the length of the one of the slots.

9. The system of claim 1, wherein at least one of the bus bars is made of aluminum or an aluminum alloy.

10. The system of claim 1, further comprising one or more concentrators electrically coupled to at least one of the bus bars.

11. The system of claim 1, wherein system comprises an expansion fitting, wherein one of the first or second bus bars is part of the expansion fitting, wherein the other of the first or second bus bars is part of an elongated bus bar assembly.

12. A system, comprising:

two or more bus bars; and

one or more fasteners configured to couple at least two adjoining bus bars of the two or more bus bars at a slotted joint;

the one or more fasteners being configured to hold the adjoining bus bars in contact with one another to enable current to pass from one of the adjoining bus bars to another of the adjoining bus bars through the contacting surfaces of the adjoining bus bars, the slotted joint being configured to reduce mechanical stress on at least one of the bus bars when the system is under at least one electrical load condition, wherein at least one of the one or more fasteners is preloaded to a predetermined range to maintain electrical connectivity between the adjoining bus bars while still providing for mechanical stress relief under the at least one electrical load condition.

13. The system of claim 12, wherein at least one of the bus bars comprising a slot, wherein one or more of the fasteners passes through the slot, wherein the slotted joint is configured to allow the fastener to move within the slot when the system is under the at least one electrical load condition.

14. The system of claim 12, wherein the slotted joint is configured to allow relative movement between the coupled bus bars in the longitudinal direction of the bus bars under the at least one electrical load condition.

15. The system of claim 12, wherein at least one of the fasteners is a threaded fastener, wherein at least one of the threaded fasteners is preloaded to a predetermined range.

16. The system of claim 12, wherein the two or more bus bars form a first segment and a second segment, wherein a total cross sectional area of the first segment is substantially equal to a total cross sectional area of the second segment.

17. The system of claim 12, wherein the two or more bus bars comprise an internal bus bar and two external bus bars, wherein the two external bus bars are coupled to opposing sides of the internal bus bar.

18. The system of claim 12, wherein the cross sectional area of the internal bus bar form is substantially equal to the total cross sectional area of the two external bus bars.

19. The system of claim 12, further comprising a power source coupled to at least one of the bus bars.

20. The system of claim 12, wherein the system comprises an additional slotted joint for at least about every 100 feet of linear run of the one or more bus bars.

21. The system of claim 12, further comprising:

one or more load devices;

at least one bus-side conductor coupled to at least one of the bus bars, the at least one bus-side conductor being made of a first material;

at least one load-side conductor coupled to at least one of the load devices, the at least one load-side conductor being made of a second material; and

at least one concentrator configured to electrically couple to at least one of the bus-side conductors to at least one of the load-side conductors.

22. The system of claim 21, wherein the concentrator comprises an interface layer, wherein the interface layer comprises a metal alloy powder weld.

23. The system of claim 12, wherein at least one of the bus bars is made of aluminum or an aluminum alloy.

24. A method, comprising:

connecting a bus bar to at least one other bus bar with one or more fasteners, at least one of the fasteners passing through a slot in one of the bus bars to form a slotted joint connecting the bus bar and the at least one other bus bar as adjoining bus bars; and

applying a torque to within a predetermined range to the one or more fasteners such that the one or more fasteners hold the adjoining bus bars in contact with one another to enable current to pass from one of the adjoining bus bars to another of the adjoining bus bars, the slotted joint being configured to reduce mechanical stress on at least one of the adjoining bus bars under at least one electrical load condition while still maintaining electrical connectivity between the adjoining bus bars.

25. The method of claim 24, further comprising:

checking the torque on the one or more fasteners at a specified interval after applying the torque to the one or more fasteners; and

if the torque level of at least one of the fasteners is no longer in the predetermined range, re-applying torque to the fasteners to bring the torque level into the predetermined range.

26. A bus system, comprising:

two or more bus bar assemblies, each of the bus bar assemblies comprising at least one bus bar;

a fitting configured to electrically couple a first one of the bus bar assemblies with at least one other of the bus bar assemblies, the fitting comprising one or more interconnect bus bars, wherein at least one of the interconnect bus bars comprise one or more slots; and

one or more fasteners configured to secure at least one of the bus bar assemblies to the fitting, wherein at least one of the fasteners is preloaded to a predetermined range to couple in at least one of the slots of the one or more interconnect bus bars to allow relative movement between the fitting and at least one of the bus bar assemblies under at least one electrical load condition to provide mechanical stress relief while still maintaining electrical connectivity between the first one of the bus bar assemblies and at least one other of the bus bar assemblies.

27. The system of claim 26, wherein at least one of the one or more fasteners is configured to move along at least a portion of one of the slots to allow relative movement between the fitting and one of the bus bar assemblies under the at least one electrical load condition.

28. The system of claim 26, wherein at least one of the bus bar assemblies comprises a stack of two or more bus bars, wherein the fitting comprises one or more interconnect bus bar assemblies, wherein the one or more interconnect bus bars of the fitting are configured to intermesh with the two or more bus bars of the two or more bus bar assemblies.

29. The system of claim 26, wherein at least one of the two or more bus bar assemblies comprises an upwardly facing channel, wherein a head of at least one of the one or more fasteners is at least partially within the channel.