======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#contactor-based-atspro-con|ATS Pro & Con]] for reasons why this may or may not be an appropriate choice for your application.// ---- \\ \\ **See warnings below** \\ ---- =====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 |}} \\ //(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]] * {{page>:warnings&nofooter}} **DANGER:** Current transformers must be connected to a device, or short-circuited before power is applied in the circuit to be measured. Current transformers are //constant current// devices, not //constant voltage// like ordinary transformers. * **A C.T. with loose leads can have lethal voltage on the terminal, possibly over 1000V.** * **Do not disconnect a C.T. when power is present in the measured circuit!**