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

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For more information visit: www.eaton.com IB140064ENInstructional BookletPage 22 Effective: April 2018 Operation and Maintenance Manual, Automatic Transfer Switch, Bypass Isolation,Contactor Type, Open/Closed Transition, ATC-900 Controller, 3000A Frame5.4 Maintenance Isolation Switch (MIS)The MIS is a 2-position, maintained contact switch marked "NOR-MAL OPERATION" and "MAINTENANCE" (see Figure 29). Whenthe switch is turned to the Maintenance position, the compart-ment power is switched off. Examples of compartment power aresense lines to the controller, power to the transformer, genertorstarts, and controller contactor control power. The MIS is placedin the "Normal Operation" position for normal ATS and Bypassoperation. The voltage to the stabs in the rear of the switch arestill powered when the MIS switch is used. If a meter is incorpo-rated, the CT lines to the DCT module or other meter will still beconnected (with power). There is a Terminal Block (TBMS) avail-able that will house a N.C. contact from the MIS switch that canbe used as a contact to show the position of the MIS switch.Figure 29. Maintenance Isolation Switch.5.5 Automatic OperationThe intelligence/supervisory circuits on Eaton transfer switchesconstantly monitor the condition of both the Source 1 and Source2 power sources. These circuits automatically initiate an immedi-ate transfer of power from the Source 1 to the Source 2 powersource when the power source fails or the voltage level dropsbelow a preset value. Transfer back to the Source 1 power sourceis automatic upon return of the Source 1 power source. Monitor-ing the power source is always performed on the line side of thepower source to which the switch is connected. The Source 1power source is usually the preferred source and the transferswitch will always seek this source when it is available and whenit is selected in the ATC-900.The intelligence/supervisory circuits will continue to function nomatter what contactor is being utilized: the ATS (#1) or theBypass (#2). This patented feature allows for a redundant auto-matic switch.5.6 Transfer to the ATS or the BypassAs mentioned previously, the contactors in the switch are identi-cal. Each can be in automatic (using the ATC-900), isolated fortesting, or the Manual mode operation. Each contactor may beremoved while the remaining contactor still remains as an auto-matic (using the ATC-900), isolated for testing, or in Manualmode. The Operating Panel shown in Figure 24 is all that isrequired to control the different modes of operation. The followingare the modes of operations and instructions. The ATS (#1) or theBypass (#2) are shown on the operating panel are marked with theleft top side being the ATS and the right top side being theBypass. The three modes are:1. Automatic operation using the controller.2. Non-Automatic electrical operation using the user three posi-tion Source Select switch.3. Manual operation, non-electrical using the paddles and tripbutton on the front of the contactor.The ATS or the Bypass can be isolated for testing or removedwhile the other contactor is on the automatic or non-automaticstate.5.6.1 Automatic (Normal) Operation1. All doors must be closed and latched. The Door Open lightshould not be flashing.2. Turn the 4 position Operation switch to the desired positionfor Automatic Operation. The Green lamp will illuminate oncethe contactor is in position.NOTICEIF A TRANSFER SWITCH WITH ANY TYPE OF ELECTRICAL OPERAT-ING CAPABILITIES IS TO BE OPERATED MANUALLY UTILIZING THEMANUAL PADDLE, IT IS STRONGLY RECOMMENDED THAT THETRANSFER CONTROL CIRCUIT FIRST BE ISOLATED. IN THE CASE OFTHE ATS DESIGN, ANY ATTEMPT TO OPERATE IN MANUAL WITH-OUT FIRST ISOLATING THE CONTROL CIRCUIT CAUSES AN AUTO-MATIC TRANSFER.WARNINGTHE VOLTAGE TO THE STABS IN BACK OF THE TRANSFER SWITCHARE STILL POWERED WHEN THE MIS SWITCH IS USED. IF A METERIS INCORPORATED, THE CT LINES TO THE DCT MODULE OR OTHERMETERS WILL STILL BE CONNECTED AND HAVE POWER. APPROPRI-ATE PPE SHOULD BE USED.WARNINGTHE CLOSED TRANSITION PRODUCT CONTAINS A SPECIALCONTACT ARRANGEMENT (OVERLAPPING CONTACTS). MISUSECAN RESULT IN DEATH, SEVERE PERSONAL INJURY, AND/ORPROPERTY.