Liebert Series 610 Abnormal Operations, Trouble Recovery, Improper Transfer, Loss of Tie Controls

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Operating Instructions

4.2.9Abnormal Operations

Improper Transfer

Transfers can not be performed unless the OK TO TRANSFER LOAD (#) TO SYSTEM (#) light turns on. This makes it difficult to begin an improper transfer.

The source feeding the UPS modules does not matter because the UPS inverter output is isolated from the rectifier.

The logic permits transfers to and from a UPS system with the UPS modules running on Utility, Bat- tery, or Engine-generator so long as the system accepting the load is running on inverter output.

Synchronization is verified by forcing the system to meet three independent criteria. First, all on-line module oscillators must be synchronized. Second, the voltage zero crossings must be within tolerance. Third, the instantaneous voltage differential between UPS system voltages must be within tolerance. But, regardless of synchronization status, a critical load will not be allowed to transfer to a system running on its bypass source. Transfers from a bypass source to a system on UPS is permitted.

Circuit Breaker Failure

If a “Close” or “Open” command to a circuit breaker fails to return a confirmation of completion within an acceptable time period the Power-Tie logic initiates corrective actions based on the system’s initial state and current state.

Loss of Tie Controls

Since UPS system independence has been stressed throughout the design of this Power-Tie configura- tion, complete loss of Tie Controls will not affect either UPS system operating in any Momentary Tie (Combined Loads Mode) configuration.

4.2.10Trouble Recovery

While failures are extremely unlikely, the Power-Tie system has been designed to restart from any system operating mode once the fault has been corrected. Refer to 1.5.5 - Modes of Operation for a description of the operating modes.

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Contents Continuous POWER-TIE Configuration Page Table of Contents Operating Instructions Initial System Start-Up 4.2 Basic OperationInter-System Isolation and Reliability FunctionSystem Flexibility Basic Dual-Bus Power-Tie one-line diagram Power-Tie systems fault isolation issues Power-Tie systems control interface diagram Control System Features Operational DescriptionMomentary Tie Transfer Controls Momentary Tie OperationIntersystem Synchronizing Intersystem Sync and Power Sharing Continuous TieContinuous Tie/Transfer/Parallel Control Tie System ComponentsModes of Operation Power-Tie system one-line diagram Continuous Power-Tie Checking for Phase, Voltage, and CapacitySelecting a Line Sync Source Synchronizing the UPS SystemsControl panel layout Separating Tied Systems Load Transfers Between UPS SystemsDesign Criteria Combined Loads on One System from Continuous Tie OperationCombined Loads on One System to Continuous Tie Operation Line Sync Signal Power-Tie system fault isolation issues Power-Tie systems fault tolerance Tie Operation Improper User OperationTransfer Operation Tie Circuit Breaker or Logic Faults What Happens If a Failure Occurs During a Power TransferRecommendations Tie Circuit Breaker Selection Hardware FailuresMimic Panel Load Transfer Controls Transfer Control Disabled Transfer Function AvailableTransfer Function Available OK to Transfer Load 1 to System Transfer Function Available OK to Transfer Load 2 to SystemContinuous Tie Control Control InhibitsManual Controls Normal Transfer Operation Configurations Maintenance Procedures Isolating Each UPS System Initial System Start-Up Basic OperationTransfer of Load Between Two Systems Maintenance Procedures Maintaining Power-Tie Components Maintenance Procedures Tie Control Logic ComponentsTrouble Recovery Abnormal OperationsImproper Transfer Circuit Breaker FailureTying the UPS Systems Continuous Parallel Operations Normal Operating ConfigurationContinuous Tie-Systems Abnormal Operations Isolation for Maintenance Power-Tie system one-line diagram Operation Scenarios/Transfer Procedures See 4.2.5 Transfer of Load Between Two Systems See 4.2.4 Isolating a UPS System for MaintenanceCombined Loads Operation See 4.2.11 Tying the UPS Systems Continuous Parallel OperationsSee 4.2.3 Maintenance Procedures Isolating Each UPS SystemOne system in bypass to Continuous Tie operation Option Operating Instructions Page Locations Technical Support/ServiceCompany Behind the Products