American Standard CH530 manual Current Overload Protection, Overload trip time versus percent RLA

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Machine Protection

and Adaptive

Control

Current Overload Protection

Motor currents are continuously monitored for over current protection and locked rotor protection. This protects the Chiller itself from damage due to current overload during starting and running modes but is allowed to reach full load amps. This overload protection logic is independent of the current limit. The overload protection will ultimately shut the unit down anytime the highest of the three phase currents exceeds the time-trip curve. A manual reset diagnostic describing the failure will be displayed.

Overload protection for the motor starts based on the Maximum Time to Transition permitted for a particular motor .

Running Over Current Protection

In the run mode, a “time-to-trip” curve is looked at to determine if a diagnostic should be called. The UCP continuously monitors compressor line currents to provide running over current and locked rotor protection. Over current protection is based on the line with the highest current. It triggers a manually resettable diagnostic shutting down

the compressor when the current exceeds the specified time-trip curve. The compressor overload time trip curve is expressed as a percent of the Rated Load Amps of the compressor and is not adjustable:

Overload Must Hold = 102 Percent RLA.

Overload Must Trip in 20 (+0 -3) seconds = 112 Percent RLA (Note the above gives a nominal 20 second must trip point of 107 Percent RLA.)

Overload Must Trip in 1.5 seconds = 140 Percent RLA (Nominal)

The linear time-trip curve is as follows:

Figure 30. Overload trip time versus percent RLA

The Maximum Acceleration Time Setting and Current Transformer Setting are factory set however can be set with the service tool;

CDHF-SVU01C-EN

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Contents X39640670030CDHF-SVU01C-EN Read these carefully Contents Literature change General InformationAbout this manual Unit NameplateGeneral Information = 560 3 stage 935 2 stage Y = 500 3 stage 835 2 stage Control Optional Packages Commonly Used AcronymsGeneral Duplex unit components front view OverviewGeneral Duplex unit components 2 stage compressor Compressor 1 or 2 2 Stage Cooling CyclePressure enthalpy curve 3 stage compressor Pressure enthalpy curve 2 stage compressor DynaView Human Interface TechView Chiller Service ToolSoftware Operation Overview Diagram Power Up DiagramSoftware States Figure Timeline Text FiguresStaging Second Compressor On CDHE/F/G sequence of operation auto to runningSatisfied Setpoint Staging Second Compressor OffCDHF/G sequence of operation lead 1/lag CDHE/F/G sequence of operation lead 2 lag Fixed Sequence Compressor 2 / CompressorCDHF/G sequence of operation equalize starts and hours Sequencing Balanced Starts and HoursCDHF/G sequence of operation combined start Simultaneous Compressor Start/ StopRestart Inhibit Restart Inhibit Start to Start Time SettingRestart Inhibit Free Starts Clear Restart InhibitOil and Refrigerant Pump Surface TemperaturesOil refrigerant pump circuit 1 or 20 100 percent RLA Base Loading Control AlgorithmGeneral Information Sequence of operation ice making running to ice making Ice Machine ControlHot Water control Control Panel Devices and Unit Mounted Devices Unit Control Panel UCPUnit Control Panel UCP User-defined language support Variable water flow through the evaporatorDynaView main processor Operator InterfaceOperator Interface How It Works Chiller Stop Prevention/Inhibit FeatureTop Level Mode Description System Reset Reference Circuit Operating Mode Chiller Operating ModeMain Screen Main Screen Data Fields TableDiagnostic Screen Back button provides navigation back to the chiller screen Operator Interface Reports Report MenuReport name Circuit Evaporator Report name System EvaporatorReport name System Condenser Report name Circuit CondenserReport name System Ashrae Chiller Log Historic Diagnostics LogHeader Screen Setting Tab screens provides a userChiller Feature SettingsCircuit Mode Overrides System Mode OverridesDisplay Settings PurgeOperator Interface Operator Interface Operator Interface Operator Interface Operator Interface Inter Processor Communications IPC3 Interprocessor CommunicationIPC3 Definitions Bus Management BindingControl panel components layout Control System ComponentsControl System Components Control Panel Devices Head Relief Request Output Machine Shutdown Manual Reset MMRMaximum Capacity Relay Compressor Running RelayExop Refrigerant Monitor Input 1A17Cdrp Condenser Refrigerant Pressure Output Trmm TRM4 Tracer Comm 4 interfaceEpro Enhanced Protection Cdrp Refrigerant Pressure Output Option 1A15 Temperature basedCondenser Pressure Output Pressure basedRefrigerant Differential Pressure Indication Output Percent RLA Output Gbas Generic Building Automation SystemExternal Chilled Water Setpoint Ecws Module CharacteristicsExternal Current Limit Setpoint Wpsr WFC Water Pressure Sensing Option1A13, 1A18, 1A19, 1A20 Dual Binary input module 1A8, 1A9, 1A11, 1A12 Quad Relay Output Status1A14 Communication interface Module 1A15, 1A16, 1A17, 1A21 Dual Analog Input/output Module Recommended Length to Run external Output signalsAnalog Input Unit mounted devices Control System Components Control System Components Electrical Sequence Control Sequence of OperationUCP and Wye-Delta Starter Control Circuits Delay time 200 msec. Opens 2K1 Control Sequence of Operation Test and start timing sequence Control Sequence OperationAFD Machine Protection Adaptive Control Momentary Power Loss MPL ProtectionOverload trip time versus percent RLA Current Overload ProtectionCurrent Limit Protection Phase Loss ProtectionReverse Rotation Protection SoftLoading Differential to Start or StopMinimum and Maximum Capacity Limit Evaporator Limit Leaving Water Temperature CutoutHead Relief Relay Low Refrigerant Temperature CutoutCutout strategy Condenser Limit Restart Inhibit High Vacuum Lockout Oil Temperature Control Outdoor Air Temperature Controls Chilled Water Reset CWRMaximum Reset Return WaterDegrees of Reset Values for start reset typesConstant Return EquationOutdoor air temperature versus degrees of reset Reset RatioReset function for return CWR Reset Ratio = 50% Return CWR Unit Startup Unit Start-Up ProceduresDaily Unit Start-Up Toxic Hazards Live Electrical ComponentsSeasonal Unit Start-Up ModeUnit Shutdown Unit Shutdown ProceduresOil Pump Heater Operation Seasonal Unit ShutdownDaily Maintenance and Checks Periodic MaintenanceMoisture Contamination Record Keeping FormsNormal Chiller Operating Characteristics Weekly MaintenanceHazardous Voltage w/Capacitors Every 3 MonthsAnnual Maintenance Off-Season MaintenanceOil Change Procedure Oil MaintenanceHeater Damage Compressor Oil ChangeReplacing Oil Filter Oil Filter ReplacementOil Supply System Problems MaintenanceOther Maintenance Requirements Hazardous Voltage w/ CapacitorsFront View with Refrigerant Pump Rotary valve in drain positionRefrigerant Charge Contains RefrigerantLeak Testing Recovery and Recycle ConnectionsCleaning the Condenser Proper Water TreatmentControl Settings Adjustments Cleaning the EvaporatorUnit Corrosion Damage Unit Preparation Purge System103 104 105 106 107 108 109 110 111 112 113 114 115 Trane