Transfer switch with bypass topology
View Patent ↗An automatic transfer switch (ATS) for supplying power to a load is provided. The ATS includes a main transfer switch portion configured to connect one of a first or second power source to the load. The ATS also includes a bypass transfer switch portion configured to form a bypass connection from either the first or second power source to the load. The bypass transfer switch portion includes (i) a first bypass switch configured to connect the first power source to the load upon closing of the first bypass switch and (ii) a second bypass switch configured to connect the second power source to the load upon closing of the second bypass switch. Further, the ATS includes a primary load connection connecting the main transfer switch portion to the load, where the primary load connection is formed at least in part by the first and second bypass switches.
1. An automatic transfer switch (ATS) configured for supplying power to an electrical load, the ATS comprising:
a main transfer switch portion configured to connect either a first power source or a second power source to the load, the main transfer switch portion comprising (i) a first main switch configured to connect the first power source to the load upon closing of the first main switch and (ii) a second main switch configured to connect the second power source to the load upon closing of the second main switch;
a bypass transfer switch portion configured to form a bypass connection from either the first power source or the second power source to the load, the bypass transfer switch portion comprising (i) a first bypass switch configured to connect the first power source to the load upon closing of the first bypass switch and (ii) a second bypass switch configured to connect the second power source to the load upon closing of the second bypass switch; and
a primary load connection connecting the main transfer switch portion to the load, wherein the primary load connection is formed at least in part by the first bypass switch and the second bypass switch, and wherein closing of either the first bypass switch or the second bypass switch severs the primary load connection between the main transfer switch portion and the load.
2. The ATS of claim 1 , wherein the primary load connection further comprises a first load-isolation contact and a second load-isolation contact, wherein the first bypass switch is connected to the first load-isolation contact when in an open state, and wherein the second bypass switch is connected to the second load-isolation contact when in an open state.
3. The ATS of claim 1 , further comprising:
a first source-isolation contact between the main transfer switch portion and the first power source; and
a second isolation-contact between the main transfer switch portion and the second power source.
4. The ATS of claim 1 , further comprising an interlock mechanism between the first main switch and the second main switch, wherein the interlock mechanism prevents the first main switch and the second main switch from closing at the same time.
5. The ATS of claim 1 , further comprising an interlock mechanism between the first bypass switch and the second bypass switch, wherein the interlock mechanism prevents the first bypass switch and the second bypass switch from closing at the same time.
6. The ATS of claim 1 , wherein the bypass connection circumvents the main transfer switch portion upon activation of the bypass transfer switch portion.
7. The ATS of claim 1 wherein the first main switch and the second main switch comprise a double throw switch.
8. The ATS of claim 7 wherein the double throw switch comprises an open position.
9. An automatic transfer switch (ATS) configured for supplying power to an electrical load, the ATS comprising:
a main transfer switch portion configured to connect either a first power source or a second power source to the load, the main transfer switch portion comprising (i) a first main switch configured to connect the first power source to the load upon closing of the first main switch and (ii) a second main switch configured to connect the second power source to the load upon closing of the second main switch;
a bypass transfer switch portion configured to form a bypass connection from either the first power source or the second power source to the load, the bypass transfer switch portion comprising (i) a first bypass switch configured to connect the first power source to the load upon closing of the first bypass switch and (ii) a second bypass switch configured to connect the second power source to the load upon closing of the second bypass switch; and
a primary load connection connecting the main transfer switch portion to the load, wherein the primary load connection is formed at least in part by the first bypass switch and the second bypass switch, and wherein closing of either the first bypass switch or the second bypass switch severs the primary load connection between the main transfer switch portion and the load;
wherein the ATS is configured such that the main transfer switch portion is electrically isolated from the load, first power source, and second power source when the bypass switch portion is activated to form a bypass connection from either the first power source or the second power source to the load.
10. The ATS of claim 9 , further comprising:
a first source-isolation contact between the main transfer switch portion and the first power source; and
a second isolation-contact between the main transfer switch portion and the second power source.
11. The ATS of claim 10 , wherein the first source-isolation contact and the second source-isolation contact each comprise self aligning jaws.
12. The ATS of claim 11 , wherein the first source-isolation contact and the second source-isolation contact are interlocked such that the first source-isolation contact and the second source-isolation contact are configured to open and close at the same time.
13. The ATS of claim 9 , wherein the primary load connection further comprises a first load-isolation contact and a second load-isolation contact, wherein the first bypass switch is connected to the first load-isolation contact when in an open state, and wherein the second bypass switch is connected to the second load-isolation contact when in an open state.
14. The ATS of claim 9 , further comprising an interlock mechanism between the first main switch and the second main switch, wherein the interlock mechanism prevents the first main switch and the second main switch from closing at the same time.
15. The ATS of claim 9 , further comprising an interlock mechanism between the first bypass switch and the second bypass switch, wherein the interlock mechanism prevents the first bypass switch and the second bypass switch from closing at the same time.
16. The ATS of claim 9 , wherein the bypass connection circumvents the main transfer switch portion upon activation of the bypass transfer switch portion.
17. In an automatic transfer switch (ATS) comprising (i) a main transfer switch portion configured to connect either a first power source or a second power source to a load (ii) a bypass transfer switch portion configured to form a bypass connection from either the first power source or the second power source to the load, and (iii) a primary load connection connecting the main transfer switch portion to the load via the bypass transfer switch portion, a method for electrically isolating the main transfer switch portion from the bypass transfer switch portion without physically separating the main transfer switch portion from the bypass transfer switch portion, the method comprising:
the bypass transfer switch portion activating to form the bypass connection from either the first power source or the second power source to the load, wherein activating to form the bypass connection severs the primary load connection connecting the main transfer switch portion to the load via the bypass transfer switch portion, wherein severing the primary load connection isolates the main transfer switch portion from the load.
18. The method of claim 17 , further comprising the bypass transfer switch portion electrically isolating the first power source and the second power source from the main transfer switch portion via respective source-isolation contacts.
19. The ATS of claim 17 wherein the first main switch and the second main switch comprise a double throw switch.
20. The ATS of claim 19 wherein the double throw switch comprises an open position.