======Auto Mains Fail Transfer Switch :: ComAp Inteli-ATS====
{{ :ats:inteliats2_70_main.jpg?direct&300|}}
This automatic transfer switch uses a [[https://www.comap-control.com/products/switchgear-control-and-protections/ats-controllers/|ComAp ATS Controller]] combined with motor contactor switching to provide a fully-featured ATS with full metering & history logging, and can also be remotely monitored.
* [[https://www.comap-control.com/products/switchgear-control-and-protections/ats-controllers/inteliats2-50/|InteliATS 50]]
* [[https://www.comap-control.com/products/switchgear-control-and-protections/ats-controllers/inteliats2-70/|InteliATS 70]] adds PLC logic blocks
====Motor Contactor Selection==
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)//
* //See the discussion at [[ats:start|ATS Pro & Con]] for reasons why this may or may not be an appropriate choice for your application.//
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**See warnings below**
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=====One-Line Diagram===
{{:ats:e117.1_r1.1_auto_transfer_switch_inteliats.png?direct&600 |}}
===Auto Mains Fail Transfer Switch==
One-line diagram, detailed schematic/wiring diagram, and parts list:
* {{ :ats:e117.1-3_r1.1_auto_transfer_switch_inteliats.pdf |}}
* {{ :ats:e117.1-3_r1.1_auto_transfer_switch_inteliats.dsn |}}
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//(DSN) files can be edited with [[:TinyCAD|]].//
=====Description of Operation===
Contactors K-U [3] and K-G [5] are mechanically and electrically interlocked to ensure that only one can be closed at a time.
===Definitions==
* **Utility Connected:** Two Green indicators (L-U, L-KU)
* **Generator Connected:** Two Blue Indicators (L-G, L-KG)
* **Load Connected:** White Indicator(s) (one per phase, if desired)
* **K-G [3], K-U [4]**: Utility & Generator Power Contactors, 400 Amp 3-pole
====Utility Power Failure==
- Starting with Utility Power being supplied to the load: Contactor K-U [3] is closed, and all timers have expired.
- Power is removed from the coil for K-U [3] if:
- Utility power fails
- Voltage on any phase exceeds minimum or maximum voltage setpoint.
- Frequency exceeds minimum or maximum setpoint
- Phase rotation is reversed
- When K-U [3] opens:
- Load is disconnected (Preventing damage to equipment caused by low voltage.)
- If utility power fails to return within 5 seconds:
- InteliATS closes KGS [6] to start the genset
- Once the generator is running, the InteliATS:
- Qualifies input for minimum, maximum voltage on all phases, correct phase rotation, minimum, maximum frequency
- Illuminates L-G (Blue) indicating generator power is OK.
- Begins countdown (5 seconds).
- K-G [5] then closes:
- Supplies generator power to the load
- Opens the neutral connection for the coil on K-U [3], preventing K-U [3] from closing by accident.
- Illuminates L-KG (Blue) indicating that generator is supplying the load.
====Utility Power Return==
- When Utility Power returns, InteliATS:
- Qualifies input for minimum, maximum voltage on all phases, correct phase rotation, minimum, maximum frequency
- Indicator L-U (Green) illuminates to confirm utility grid voltage is acceptable
- Begins time delay (15 minutes), which ensures:
- The utility grid has time to stabilize
- Delays adding loads to the grid after an outage
- Eliminates short-cycling if the grid drops again shortly after returning
- Provides a minimum run-time for the generator to ensure it gets up to operating temperature
- Opens the coil for K-G [5]:
- Disconnects load from Generator
- Connects neutral of K-U [3] coil
- K-U [3] closes after setpoint time-delay (as short as 1mS)
- Connects load to Utility Grid
- Disables K-G [5] by disconnecting neutral of coil
- Illuminates L-KU (Green), indicating Utility/Grid is supplying load
- Begins time delay (2 minutes) for Generator cool-down (running with no load)
- Opens KGS [6] to disconnect the generator auto-start signal
- Genset stops
====Force Generator Operation ==
* Operating S2, Auto/Gen, to the "Gen" position forces selection of Generator by InteliATS
* InteliATS will start generator, qualify power, then turn off K-U [3] and turn on K-G [5] after setpoint delay (as short as 1mS).
* Switching S2 back to Auto will switch back to Utility power if it is qualified based on normal setpoint limits.
====Manual Bypass===
Voltage, frequency, and phase monitoring is inactive while either bypass mode is active!
* Operating S3, Manual Bypass, forces selection of Utility or Generator power and bypasses InteliATS controls, switching InteliATS to "OFF" Mode.
* S4 is a 3-position center return selector switch with "ON" and "OFF".
* S4 is only enabled when S3 is not in "AUTO".
* When S3 is in either "City" or "Gen" bypass mode, S4 switches ON or OFF the respective contactor.
* S3 is mounted inside a protective shroud to prevent casual operation.
* Placing S3 in the City (Utility) disables genset auto-start and K-GC (5)
* To turn on City/Utility power, momentarily turn S4 to the "ON" position.
* To turn off the City/Utility Power, momentarily turn S4 to the "OFF" position.
* Low voltage from City power will not open contactor K-UC (3) until the voltage falls to approximately 60VAC.
* Placing S3 in the Generator position disables K-UC (3), City Power and starts the Generator.
* To switch on Generator power, momentarily turn S4 to the "ON" position once generator is up to speed.
* To turn off the Generator Power, momentarily turn S4 to the "OFF" position.
* Power to the load will remain OFF until S3 is returned to AUTO, or switched to CITY.
* If the generator fails (or runs out of fuel) and the voltage falls below approximately 60VAC, contactor K-UG (5) will open by itself.
* Allowing this to happen can damage equipment, including the generator diodes.
====Emergency Stop===
* Operating the Emergency Stop (E-Stop) mushroom switch immediately disconnects all power sources and shuts down genset, if it is operating.
* The E-Stop must be turned clockwise to release the latched condition, and the alarm reset on the InteliATS in order to return to normal operation.
=====Bill of Materials==
**//[Incomplete, work in progress]//**
====117 ATS -- Automatic Transfer Switch-Contactor===
* [[https://docs.google.com/spreadsheets/d/1r8JlMTjobZA3-YeLz29EerO8OxSNKXO5SXB6vngvN9Y/edit?usp=sharing|BOM 117 -- Google Sheets]]
* [[https://docs.google.com/spreadsheets/d/e/2PACX-1vTpnSXQxSW-pyEPUDI_RqkSWwlRZ5bm6xUZVdUwxoYJp45-My7mLLED89SG-gxo4DX0bJ0KjPFYXsjP/pubhtml?gid=0&single=true|BOM 117 -- Web Page]]
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