Current balancing for automatic transfer switches

Patent metadata

Field	Value
Publication number	US-11244794-B2
Application number	US-201816756975-A
Country	US
Kind code	B2
Filing date	Oct 18, 2018
Priority date	Oct 19, 2017
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

An automatic transfer switch includes a first phase switch component having a first plurality of cassettes, and at least one outer bus component disposed at an outer side of the first phase switch component. The automatic transfer switch additionally includes a first plate which is disposed on the outer side of the first phase switch component at a terminal end of the first phase switch component. The first plate is structured to increase impedance on an outer bus component of the first phase switch component to rebalance current along the first phase switch component.

First claim

What is claimed is:

1. An automatic transfer switch comprising:
a first phase switch component comprising a first plurality of cassettes;
at least one outer bus component disposed at an outer side of the first phase switch component; and
a first plate disposed on the outer side of the first phase switch component at a terminal end of the first phase switch component,
wherein the first plate is structured to increase impedance on an outer bus component of the first phase switch component to rebalance current along the first phase switch component.

2. The automatic transfer switch of claim 1 , further comprising:
a second plate disposed between the first phase switch component and a second phase switch component; and
a third plate disposed between the second phase switch component and a third phase switch component.

3. The automatic transfer switch of claim 2 , wherein:
the first and second plates comprise laminations of electric steel.

4. The automatic transfer switch of claim 2 , wherein:
each of the first and second plates comprises a first lamination assembly having a first thickness; and
the third plate comprises a second lamination assembly having a second thickness which is smaller than the first thickness.

5. The automatic transfer switch of claim 2 , further comprising:
a plurality of movable contact members including at least one first movable contact member at a first location, at least one second movable contact member at a second location, and at least one third movable contact member at a third location,
wherein the at least one first movable contact member is configured to move the first plurality of cassettes, the at least one second movable contact member is configured to move the second plurality of cassettes, and the at least one third movable contact member is configured to move the third plurality of cassettes,
wherein at least one of the first and second plates comprises a first lamination assembly,
wherein a first air gap is provided between at least a first cassette and a second cassette of the first plurality of cassettes, and
wherein a second air gap is provided at least between a first cassette and a second cassette of the second plurality of cassettes.

6. The automatic transfer switch of claim 2 , wherein an air gap is disposed between at least one of the plurality of movable contact members and another of the plurality of movable contact members.

7. The automatic transfer switch of claim 2 , wherein a distance between the second and the third plates is less than a distance between the first and the second plates.

8. The automatic transfer switch of claim 3 , wherein the laminations of electric steel comprise a plurality of layers of electric steel which are connected to each other.

9. The automatic transfer switch of claim 2 , wherein:
each of the first and second plates comprises a first lamination assembly having a first plurality of sheets, and
the third plate comprises a second lamination assembly having a second plurality of sheets having fewer sheets than the first plurality of sheets.

10. An automatic transfer switch assembly, comprising:
a first phase switch component comprising a plurality of conductors, wherein the plurality of conductors comprise a plurality of interior conductors disposed between a first outer conductor on a first side of the first phase switch component and a second outer conductor on a second side of the first phase switch component;
wherein at least one of the conductors comprises a cut portion configured to increase impedance along the first phase switch component to rebalance current along the first phase switch component.

11. The automatic transfer switch assembly of claim 10 , wherein the first phase switch component comprises a plurality of contact cassettes.

12. The automatic transfer switch assembly of claim 10 , further comprising a second phase switch component,
wherein the first outer conductor comprises the cut portion and is configured to increase the impedance along the first phase switch component so as to exceed an impedance of the second phase switch component.

13. The automatic transfer switch assembly of claim 10 , wherein the first outer conductor comprises a resistive coating on at least a portion of the first outer conductor.

14. The automatic transfer switch assembly of claim 13 , wherein a cross section of the first outer conductor is reduced relative to the second outer conductor such that an impedance of the first outer conductor is higher than an impedance of the second outer conductor.

15. The automatic transfer switch assembly of claim 10 , wherein:
the first phase switch component connects a first source and a load, and
a plurality of cassettes provided in the first phase switch component includes at least one non-conductive cassette.

16. The automatic transfer switch assembly of claim 11 , further comprising:
a gap provided between adjacent contact cassettes of the plurality of contact cassettes.

17. A method, comprising:
arranging a first switch component comprising a first plurality of cassettes, the first plurality of cassettes comprising outer cassettes and interior cassettes disposed between the outer cassettes;
disposing a first plate on a first outer conductor located at a first outer side of the first switch component at a first terminal end of the first switch component; and
disposing a second plate on a second outer conductor located at a second outer side of the first switch component at a second terminal end of the first switch component, the first and second outer conductors sandwiching a plurality of interior conductors therebetween, and
rebalancing current along the first phase switch component so as to increase impedance along the first phase switch component.

18. The method of claim 17 , further comprising:
removing at least one interior conductor located between the first outer conductor and the second outer conductor; and
arranging first and second lamination plates around the first and second outer conductors, respectively.

19. The method of claim 17 , further comprising:
controlling an amount of impedance on the outer conductors so as to direct a flow of current to an interior conductor disposed between the outer conductors.

20. The method of claim 17 , wherein rebalancing current along the first phase switch component comprises at least one of (1) reducing a size of at least one of the conductors, (2) reducing a cross sectional area of at least one of the conductors, or (3) providing a resistive element or coating on at least one of the conductors.

Assignees

• Cummins Power Generation Ip

Inventors

• Supriya Amrit
• Zhou Wangwei

Classifications

• H02J9/06 Primary

  with automatic change-over {, e.g. UPS systems} · CPC title

• H01H2300/018

  Application transfer; between utility and emergency power supply · CPC title

• H02J9/068

  Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection · CPC title

• H01H9/40

  Multiple main contacts for the purpose of dividing the current through, or potential drop along, the arc · CPC title

• H01H9/0072 Primary

  particular to three-phase switches (synchronous switching H01H9/563) · CPC title