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--- ats:relay [2024/05/25 12:30] – ↷ Links adapted because of a move operation 34.74.75.141
+++ ats:relay [2024/06/10 22:38] (current) – [Auto Mains Fail Transfer Switch :: Relay Logic] Alan Shea
@@ Line 1: / Line 1: @@
-======Auto Mains Fail  Transfer Switch====
+======Auto Mains Fail Transfer Switch :: Relay Logic ====
+This Auto Mains Fail or Automatic Transfer Switch uses [[https://en.wikipedia.org/wiki/Relay_logic|"Relay Logic"]] to control two motor contactors (rated 100A or above) to transfer power to a load circuit between utility power and a standby generator.
-===Pro & Con===
+{{ :ats:rs-pro_136-5381.png?direct&150|}}
-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.
+One or more [[ats:meters|multi-meters]] can be included but are not shown.((Three current transformers per meter are also required.))
-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):
+====Motor Contactor Selection==
-  - They are not manufactured as Automatic Transfer Switches (ATS) or approved by a testing lab for emergency power system use.
+The appropriate size of motor contactors should be selected based on the load served and the genset size. The 400A frame is a good general purpose selection, but smaller or larger can substituted. Recommended source: [[https://www.factorymation.com/Contactors_Overloads_qs/Metasol-Contactors-Overloads-9-to-800A?Coil_Voltage=240V-AC-Class&Nominal_Amps=150,225,400,800|FactoryMation.com]] //(225A frame and larger have 100-240VAC/DC coils)//
-  - They are not mechanically held.((See [[https://web.archive.org/web/20210315105023/http://www.mikeholt.com/download.php?file=PDF/11_Generators_and_Standby_Power_Systems.pdf|http://www.mikeholt.com/download.php?file=PDF/11_Generators_and_Standby_Power_Systems.pdf]]))
-Optional Standby systems as defined in [702.4] are not bound by these legal requirements for transfer switches.
+  * //See the discussion at [[ats:start|ATS Pro & Con]] for reasons why this may or may not be an appropriate choice for your application.//
+\\
-The biggest disadvantage of a packaged ATS is that the contacts are typically listed for a maximum of 5000 transfers at rated load, at which point the contacts must be replaced, and frequently the electro-mechanical actuator as well. In locations where electric power is reliable, this is typically not an issue as 5000 transfers will take several decades to accumulate. In locations with unreliable power this number of transfers can be accumulated in just two or three years.
+----
+\\
-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.
+<WRAP center round alert 60%>
+\\
-===Alternative Controller===
+**See warnings below**
-{{ :cp:inteliats2_70_main.jpg?direct&200|}}
+</WRAP>
-As an [[ats:inteli|alternative]] to the relay logic depicted below, a [[https://www.comap-control.com/products/switchgear-control-and-protections/ats-controllers/|ComAp ATS Controller]] combined with the contactor switching provides an ATS with full metering & logging, and can also be remotely monitored.
+\\
+----
-===One-Line Diagram===
+=====One-Line Diagram===
-{{ :cp:e116.1_r4.1_-_transfer_switch.png?600 |}}
+{{ :ats:e116.1_r6_auto_transfer_switch.png?direct&600 |}}
+===Auto Mains Fail Transfer Switch -- Selector Switch==
 <WRAP col2>
-==Auto Mains Fail Transfer Switch==
+One-line diagram, detailed schematic/wiring diagram, and parts list:
-  * {{ :cp:e116.1-3_r4.1_-_transfer_switch.pdf |E116.1-3 r4.1 Transfer Switch (PDF)}}
+  * {{ :ats:e116.1-3_r6_auto_transfer_switch_selector.pdf |E116.1-3 r6 Transfer Switch (PDF)}}
-  * {{ :cp:e116.1-3_r4.1_-_transfer_switch.dsn |E116.1-3 r4.1 Transfer Switch (DSN)}}
+  * {{ :ats:e116.1-3_r6_auto_transfer_switch_selector.dsn |E116.1-3 r6 Transfer Switch (DSN)}}
+\\
+//(.dsn) files can be edited with [[:TinyCAD|]].//
-==Auto Mains Fail Transfer Switch -- Selector Switch==
-  * {{ :cp:e116.1-3_r5.2_auto_transfer_switch_selector.pdf |E116.1-3 r5.2 Transfer Switch (PDF)}}
-  * {{ :cp:e116.1-3_r5.2_auto_transfer_switch_selector.dsn |E116.1-3 r5.2 Transfer Switch (DSN)}}
 </WRAP>
-//(DSN) files can be edited with [[:TinyCAD|]].//
 ====Description of Operation===
@@ Line 100: / Line 101: @@
   * [[https://www.factorymation.com/ShopAll-Pushbuttons-Indicators?Category_=22mm-Pilot-Devices&Item_Type=Contact-Blocks,Knob-Selector-Switch,Lever-Selector-Switch|Alternate selector switch choice]]
-<html><iframe width="800px" height="600px" src="https://docs.google.com/spreadsheets/d/1_wC8IrVGSBzF0N8M5elPFTP66rg2xVx9F6NlgHCPepY/pubhtml?gid=0&amp;single=true&amp;widget=true&amp;headers=false"></iframe></html>
+<html><iframe width="950px" height="600px" src="https://docs.google.com/spreadsheets/d/1_wC8IrVGSBzF0N8M5elPFTP66rg2xVx9F6NlgHCPepY/pubhtml?gid=0&amp;single=true&amp;widget=true&amp;headers=false"></iframe></html>
+{{page>:warnings&nofooter}}

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