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cp:ats [2022/10/26 01:14] – [One-Line Diagram] Alan Shea | cp:ats [2024/04/16 05:26] – [Pro & Con] Alan Shea | ||
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===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 otherwise be carried in an airline suitcase. That in particular makes this design more suitable for remote locations, as the parts can be carried in and assembled on location in a short time. | An ATS is also physically large compared to a set of contactors, which can otherwise be carried in an airline suitcase. That in particular makes this design more suitable for remote locations, as the parts can be carried in and assembled on location in a short time. | ||
+ | ===Alternative Controller=== | ||
+ | {{ : | ||
+ | As an alternative to the relay logic depicted below, a [[https:// | ||
===One-Line Diagram=== | ===One-Line Diagram=== | ||
{{ : | {{ : |