Emerson NT5C06D SEN Fail fault, Erratic load fault, Current or voltage float fault, Float

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48 Troubleshooting

SEN FAIL fault

Fault symptom	Possible causes

SEN FAIL	One or both remote sense leads is disconnected.

	DC breaker is open.

	Rectifier is still in walk-in.
	Sense leads are reversed.

Erratic load fault

Fault symptom	Possible causes

Erratic load	Requirement exceeds total rectifier capacity.

Current or voltage float fault

Fault symptom	Possible causes

Current or voltage	With paralleled units, the float and/or equalize is
float	misadjusted causing one or more units to carry the load.
	Unit is in 'equalize' mode and paralleled units are not.

	Remote sense lead has excessive impedance or are not
	connected on one or more rectifiers.

	System batteries are in a recharge mode after AC
	outage.

	Current share mode selection is not the same for all
	units.

	Forced share line is disconnected. (in FS only)

UM5C06D ( 169-2071-504 ) P0831010 Standard 7.00 May 2001

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Contents Helios Rectifier 25/48 Single Phase -48V, 25 a P0831010 Standard 7.00 MayPage Helios Rectifier 25/48 Single Phase -48V, 25A Page Publication history This page is left blank intentionally Contents Contents List of Procedures List of FiguresShelf List of TablesThis page is left blank intentionally Introduction DescriptionMPS75 NT5C10CX  power shelf 23-inch ApplicationsEquipment Identification MPS75 Modular Power Shelf-NT5C10C with 8-pin signal cables NT5C06D Switch Mode Rectifier Specifications Electrical specificationsElectrical specifications Efficiency and Power Factor Output noise and rippleReliability Heat DissipationEnvironmental specifications Operating TransportationStorage Specifications Installation and start up Installing the power shelfTools and test equipment Wiring the power shelf Procedure 1 Installing the power shelf Step ActionInstalling the AC power AC cable wire sizeAWG for each rectifier Max for each rectifierDC Conductors Installation Power shelf individual AC connectionControl and Alarm Connections Connecting the DC power shelfRectifier Failure Alarm Rectifier 1 fail alarmRectifier 2 fail alarm Rectifier 3 fail alarmAC Line Fail Alarm Fan AlarmDC Circuit Breaker Sense FailA0384387 SIG NAL Cables FRO M Shelves Installing the rectifier Factory settingVerification Procedure 4 Starting up the rectifier Step High Voltage Shutdown Hvsd AdjustmentFloat Voltage Adjustment Rectifier meter accuracy= 52.2 + .15 V = 52.35 Ii Forced Share Current Limit Verification CLLoad Sharing Load Share Adjustment Procedure Procedure 5 Adjusting the load share Step ActionSlope Load Share Forced Load ShareOperation Features Front panel controlsLocal float / equalize control High voltage shutdown Hvsd localStart-up delay IndicatorsRectifier failure alarm RFA Fan failure alarmSense fail alarm SEN Fail Local ON/OFF control AC breakerRemote ON/OFF control Remote voltage sensingSequential start Parallel operationDischarge of output capacitors Local / remote high voltage shutdown reset Power interface edge connectorInput AC voltage monitor Thermal shutdownSignal interface connector Power interface connectionsControl signal connections Maintenance Procedure 6 Adjusting the float / equalize StepFloat / equalize High voltage shutdown Hvsd Cooling fanFan failure Fan replacement NT5C06D rear view Power shelf This page is left blank intentionally Troubleshooting Alarm indication RFA faultSystem fault diagnosis Fault symptom Possible causes SEN Fail fault Erratic load faultCurrent or voltage float fault Fault symptom Possible causesAppendix a Replacement parts CPCAppendix a Replacement parts Appendix B Technical service assistance Local toll-free prefixesCountry Appendix B Technical service assistance Toll-free technical assistance numbersUnited States Canada Europe Asia and the Pacific List of terms and acronyms Rectifier Fail Alarm Normally OpenNorthern Telecom Sense FailPage Part of Emerson Network Power