Eaton ATC-900 Operation And Maintenance Manual

Also see for ATC-900: Instruction booklet Manual Operation and maintenance manual Instruction booklet Operation and maintenance manual

Contents

For more information visit: www.eaton.com IB140064ENInstructional BookletPage 4 Effective: April 2018 Operation and Maintenance Manual, Automatic Transfer Switch, Bypass Isolation,Contactor Type, Open/Closed Transition, ATC-900 Controller, 3000A Frame2.4 General InformationTransfer switches are used to protect critical electrical loadsagainst loss of power. The Source 1 power source of the load isbacked-up by a Source 2 power source. A transfer switch is con-nected to both the Source 1 and Source 2 power sources and sup-plies the load with power from one of these two sources. In theevent that power is lost from the Source 1 power source, thetransfer switch transfers the load to the Source 2 power source.This open transition transfer can be automatic or manual, depend-ing upon the type of transfer switch equipment being used. OnceSource 1 power is restored, the load is automatically or manuallytransferred back to the Source 1 power source, again dependingupon the type of transfer equipment being used.In addition, the closed transition feature may be applied where it isdesirable to avoid any momentary power interruptions. If bothsources are acceptable as determined by the ATC-900 controller,a make-before-break transition is performed during a transfer orretransfer operation.2.4.1 Transfer SwitchOpen/closed transition bypass isolation type automatic transferswitches consist of four basic elements.1. Main contacts to connect and disconnect the load to and fromthe source of power.2. Intelligence/supervisory circuits to constantly monitor the con-dition of the power sources and thus provide the intelligencenecessary for the switch and related circuit operation, includ-ing safety related logic.3. Switching devices to effect the transfer of the main contactsfrom source to source.4. Voltage selection, bypass selection, and transformer panel.The Bypass Isolation Switch shown in Figure 2 is designed forapplications where maintenance, inspection, and testing must beperformed while maintaining continuous power to the load. Thisis typically required in critical life support systems and standbypower situations calling for safe system maintenance with nopower disruptions. Such a design allows for the quick removal ofeither (patented) switching devices for inspection, maintenance,or replacement. See Section 3 for more information.2.4.2 Design ConfigurationThe Eaton transfer switch is a rugged, compact design utilizingpower contactors to transfer essential loads from one powersource to another. Open transition switching devices are inter-locked (Mechanically and Electrically) to prevent both switchingdevices from being closed at the same time.The switching devices are in a compact vertical arrangement. Thelogic of the switch follows the Product Line's smartEST (smartEaton Switch Technology) switch approach. It contains the pat-ented Dual Automatic Contactor operation. The controller is tiedto both contactors making them both totally automatic. A stan-dard maintenance switch (MIS) and slider right door make theswitch very safe and easy to maintain and work with. The enclo-sure is free standing, and is seismic certified.The switching devices have a high withstand/close rating (Table1). Figure 3 shows the schematic of the Bypass Isolation Switch.As mentioned, the unit can also be operated as a redundant auto-matic switch with the controller being full activated with the pri-mary (ATS) or redundant (Bypass) switch. There is not a need tomove the Bypass contactor to the ATS slot if the ATS contactor isremoved for a dual redundant switch to operate. One contactorcan perform Open or Closed operations.Table 1. System Coordination Information - UL1008 Withstand Closing RatingsTested in accordance with UL1008.See specific breaker listing for all current breakers listed per UL1008 specification.Seismic rated at 125%WARNINGTHE CLOSED TRANSITION PRODUCT CONTAINS A SPECIAL CON-TACT ARRANGEMENT (OVERLAPPING CONTACTS). MISUSE CANRESULT IN DEATH, SEVERE PERSONAL INJURY, AND/OR PROPERTYDAMAGE.TRANSFER SWITCHAMPERE RATINGSHORT-CIRCUIT (0.05 SEC)600V (kA)SHORT-TIME (0.50 SEC)600V (kA)FUSE PROTECTIONFUSE TYPES: L600V (KA)UL 10081600 100 85 2002000 100 85 2002600 100 85 2003000 100 85 200