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cp:ats [2022/10/26 01:05] – [116 ATS -- Automatic Transfer Switch-Contactor] Alan Shea | cp:ats [2024/04/29 18:33] (current) – Alan Shea | ||
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- | ======Transfer Switch==== | + | ======Auto Mains Fail |
===Pro & Con=== | ===Pro & Con=== | ||
- | Generator transfer switches using industrial motor-control contactors have the advantage of simplicity and long-life, typically | + | Generator transfer switches using industrial motor-control contactors have the advantage of simplicity and long-life, typically over 500,000 operations at rated load. They also use standard off-the-shelf components that can be purchased almost anywhere. |
The primary disadvantage is that they do not meet National Electrical Code requirements in the United States for Automatic Transfer Switches for emergency and legally required standby power use. They do not satisfy the two requirements of NEC [700.5(C)] and [701.5(C)] (2011): | The primary disadvantage is that they do not meet National Electrical Code requirements in the United States for Automatic Transfer Switches for emergency and legally required standby power use. They do not satisfy the two requirements of NEC [700.5(C)] and [701.5(C)] (2011): | ||
- They are not manufactured as Automatic Transfer Switches (ATS) or approved by a testing lab for emergency power system use. | - They are not manufactured as Automatic Transfer Switches (ATS) or approved by a testing lab for emergency power system use. | ||
- | - They are not mechanically held.((See [[http:// | + | - They are not mechanically held.((See [[https:// |
Optional Standby systems as defined in [702.4] are not bound by these legal requirements for transfer switches. | Optional Standby systems as defined in [702.4] are not bound by these legal requirements for transfer switches. | ||
- | The biggest disadvantage of an ATS is that the contacts are typically | + | The biggest disadvantage of a packaged |
- | An ATS is also physically large compared to a set of contactors, which can be carried in an airline suitcase | + | An ATS is also physically large compared to a set of contactors, which can otherwise |
+ | |||
+ | ===Alternative Controller=== | ||
+ | {{ : | ||
+ | As an alternative to the relay logic depicted below, a [[https:// | ||
===One-Line Diagram=== | ===One-Line Diagram=== | ||
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<WRAP col2> | <WRAP col2> | ||
==Auto Mains Fail Transfer Switch== | ==Auto Mains Fail Transfer Switch== | ||
- | * {{ : | + | * {{ : |
- | * {{ : | + | * {{ : |
- | \\ | + | |
==Auto Mains Fail Transfer Switch -- Selector Switch== | ==Auto Mains Fail Transfer Switch -- Selector Switch== | ||
- | * {{ : | + | * {{ : |
- | * {{ : | + | * {{ : |
</ | </ | ||
+ | //(DSN) files can be edited with [[: | ||
====Description of Operation=== | ====Description of Operation=== |