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American Standard CH530 Current Limit Protection, Reverse Rotation Protection

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CDHF-SVU01C-EN

74

Current Limit Protection

Current Limit Protections exist to

avoid motor current overload and

damage to the compressor motor

during starting and running.

Compressor motor current is

continuously monitored and current

is controlled via a limit function that

to prevent running into over current

diagnostic trips.

The current limit control logic

attempts to prevent the motor from

shutting down on a diagnostic trip by

limiting compressor current draw

relative to an adjustable current limit

DynaView™ Current Limit Setpoint.

This setpoint can also be lowered to

provide electrical demand limiting on

the unit as required. This could also

be set to allow the Chiller to continue

to run at a lower load to avoid

tripping off via a diagnostic.

The Current Limit function uses a PID

algorithm (Similar to the Leaving

Water Temperature control) that

allows the chiller to run at the

Current Limit Setpoint. At machine

startup, or with any setpoint change

the new current limit setpoint

reached after the is filtered setpoint

time elapses. The minimum current

limit setpoint is default set to 40

percent RLA (20-100 percent). The

filtering time is default set to 10

minutes (0-120 minutes), however

these can be altered via the service

tool. This filtered setpoint allows for

stable control if the Current Limit

setpoint is adjusted during a run.

The Current Limit Setpoint (CLS) can

be changed from: Front Panel,

External Analog input (with GBAS

(external) option), or Tracer (Tracer

option). However, If present Tracer

current setpoint has the highest

priority, unless disabled in the

DynaView™ Setpoint source override

menu. The External CLS has second

priority, and will be used if Tracer is

disabled or not installed. The Front

Panel Setpoint has the lowest

priority, and will be used if Tracer

and the External CLS are both

disabled.

Phase Loss Protection

Loss of phase detection protects the

chiller motor from damage due to a

single-phasing condition. The

controls will shut down the chiller if

any of the three phase currents

feeding the motor are lost. The

shutdown will result in a latching

diagnostic indicating the failure. The

motor is protected from over-current

during a single-phase condition by

the Current Overload Protection

feature. Phase Loss Protection

provides redundant protection and a

diagnostic that more accurately

describes the fault.

Reverse Rotation Protection

This function protects the

compressor from being driven in the

reverse direction. Incorrect phase

rotation detection results in a

manually resettable diagnostic.

Phase Reversal protection is default

to Enable, however can be disabled

via the service tool.

Machine Protection

and Adaptive

Control

Contents

Main Warnings and Cautions Contents Typical Product Description Block Unit Nameplate Literature change About this manual Page Page Commonly Used Acronyms Figure 1. General Duplex unit components - front view Page Cooling Cycle Page Page Page Figure 7. Sequence of operation overview. Figure 8. CDHE/F/G sequence of operation: auto to running Figure 9. CDHE, CDHF, and CDHG sequence of operation: running Page Figure 12. CDHF/G sequence of operation: lead 1/lag 2 Figure 13. CDHE/F/G sequence of operation: lead 2 lag 1 Figure 14. CDHF/G sequence of operation: equalize starts and hours Figure 15. CDHF/G sequence of operation: combined start Page Oil and Refrigerant Pump Surface Temperatures! Page Base Loading Control Algorithm: Page Ice Machine Control Figure 18. Sequence of operation: ice making: running to ice making Figure 19. Sequence of operation: ice making: stopped to ice to ice building complete Hot Water control Unit Control Panel (UCP) Control Panel Devices and Unit Mounted Devices Figure 20. Left control panel Unit Control Panel (UCP) Tracer CH530 Chiller Controller Figure 21. DynaView main processor Page Page A general description of the top level modes is show in the following table. Figure 22 Figure 23 Page Main Screen Data Fields Table Diagnostic Screen Page Page Report Menu Report name: System Evaporator Report name: Circuit Evaporator Report name: System Condenser Report name: Circuit Condenser Report name: System ASHRAE Chiller Log Report name: Circuit ASHRAE Chiller Log Historic Diagnostics Log Page Chiller Feature Settings System Mode Overrides Circuit Mode Overrides (0 to disable) Purge Display Settings { Page Page Page Page Control Panel Internally mounted devices Interprocessor Communication Inter Processor Communications IPC3 Page Page Control Panel Devices Head Relief Request Output Maximum Capacity Relay Compressor Running Relay Machine Shutdown Manual Reset (MMR) Chilled and Condenser Water Flow Interlock Circuits Refrigerant Monitor Input 1A17 Page CDRP Refrigerant Pressure Output Option 1A15: Figure 25. Condenser pressure based output Page GBAS (Generic Building Automation System) Figure 27. Voltage versus percent RLA External Chilled Water Setpoint (ECWS) External Current Limit Setpoint WPSR (WFC Water Pressure Sensing Option) Module Characteristics Page Recommended Length to Run external Output signals Unit mounted devices Page Page Electrical Sequence UCP and Wye-Delta Starter Control Circuits Page Page Figure 24. Test and start timing sequence Page Momentary Power Loss (MPL) Protection. and starter module remain powered) Figure 29. Sequence of operation: momentary power loss, (DynaView Current Overload Protection Figure 30. Overload trip time versus percent RLA Current Limit Protection Reverse Rotation Protection Differential to Start or Stop SoftLoading Evaporator Limit Leaving Water Temperature Cutout Low Refrigerant Temperature Cutout Page Condenser Limit Restart Inhibit Page Page Controls Chilled Water Reset (CWR) Return Water = Maximum Reset. Outdoor Air Temperature Where Constant Return Reset Ratio: Figure 32. Outdoor air temperature versus degrees of reset Page Page Page Unit Start-Up Procedures Unit Startup Seasonal Unit Start-Up Unit Startup Live Electrical Components! Toxic Hazards! Unit Shutdown Unit Shutdown Procedures Seasonal Unit Shutdown Oil Pump Heater Operation! Trouble Analysis Moisture Contamination! Hazardous Voltage w/Capacitors! Normal Chiller Operating Characteristics Weekly Maintenance Every 6 Months Every 3 Months Off-Season Maintenance Annual Maintenance Oil Maintenance Compressor Oil Change Oil Change Procedure Heater Damage! Oil Maintenance Replacing Oil Filter Other Maintenance Requirements Oil Supply System Problems! Hazardous Voltage w/ Capacitors! Figure 37. Rotary valve in drain position Refrigerant Charge Contains Refrigerant! Recovery and Recycle Connections Leak Testing Figure 38. Typical chemical cleaning setup Cleaning the Condenser Proper Water Treatment! Unit Corrosion Damage! Cleaning the Evaporator Control Settings and Adjustments Purge System Unit Preparation Contains Refrigerant! Live Electrical Components!