Maintenance system for rotating machines with electrical connection

Description of the ProcessMotor / Generator / TurbineCurrent TransformersOnline MCM SystemAlgorithmAlert

Induced EMF

Fleet managementWirelessGlobal control centerLocal control roomInternet

Diagnostic ProcessSignal ProcessingTime domainFrequency domainT-F domainMotorCharacteristicsModelFeaturesAnalysisAggregationDecisionProcess

Adaptive Algorithm• Can work with:• Soft Starters• Variable Speed Drives (VSD)• Generators

FaultsMechanical faults• Broken bar• Cracks in rotor• Imbalance• Eccentricity• Bearings• FOD• Looseness• ChipFailure rate of different machineriesothers24%rolling bearing29%valve6% sliding bearing6%seal7%slide way13%gear7%oil pump8%Electric faults• Faults in VSD & voltage soft starters• Electricity break down & shocks* As monitored at "Rourkela Steel Plat

Phase3 pilot at Nesher Israel Cement

The Algorithm

Model based fault detectionPhasesActual featureyaΣƐ = ya - ymModeled featureymƐ

The Model (Training)

InnovationPhase 1recordingPhase 2recordingPhase 1integration++ HP filterPhase 2Integration+ HP filterNext recording processCOHERENCEyesC > ThresholdnoTRAINING

Examples

Pilot in Gershon KleinMotors repair

Gear motor 7.5HP 1400RPM

Gear motor 7.5HP 1400RPMBroken bearing

Gear motor 7.5HP Waveformbefore repairafter repair

Gear motor 7.5HP Spectrum

Gear motor 7.5HP Coherence

USHPIZ 40HP 980RPM

USHPIZ 40HP Spectrumdust– background noises during running

USHPIZ 40HP SpectrumSpectral comparisonEccentricity after the repairAt the repair, newbearings where replacedbut one of them was notassembled correctly.

USHPIZ 40HP Coherence

Pilot in Nesher Ramle

Results and comparison with a competitor based onvibrationsMOTOR S\NNominalPower“PHASE3”diagnosis7-43-165 DOL 25HP Normal Normal7-76-635 DOL 30HP Normal Normal7-41-090 SOFT 152HP Load noises – Interrupted loadoperation“TISAR” diagnosisLoad wear7-44-750 SOFT 110kW Normal Normal7-43-105 DOL 10HP Load noises – Interrupted loadoperationLoad wear7-41-133 DOL 40HP Normal Normal7-44-880 SOFT 250HP Normal Normal7-44-710 VSD 800HP Normal Normal7-26-350 VSD 75kW Normal normal7-26-390 VSD 75kW Assembling fault Normal7-41-390 DOL 40HP Normal Motor looseness7-41-740 DOL 40HP Normal Motor looseness

7-41-090 Soft 152HP 82A WaveformTIMETIME ZoominFAULT: Noises from Load

7-41-090 Soft 152HP 82A Spectrumno noiseswith noisesFAULT: Noises from Load

7-41-090 Soft 152HP 82A Coherenceno noiseswith noisesFAULT: Noises from Load

7-41-090 Soft 152HP 82A cont.TIME-FREQUENCYTIME-FREQUENCY ZoominSpectrograms, T-F domain

Pilot in MILU-OF

The System – CMG Motor no. 14 +Compressor, broken bar fault• Features:Max Power 400kWNominal Speed 3000 RPM• Complains:Strong VibrationsHigh Temperatures on CoilsA Crack on Ground underthe Motorlong and wide crack

Current waveformsData of the 2 phases R and S in Time DomainZoom in 1Changes in RMS

SpectrumAnomalies – indications of a mechanical fault in Motor

Order SpectrogramSynchronized spectrogram to the supply frequency (~50hz)Order 1 means 50hzSidebands of the rotor speed higher harmonyThe rotor speed is also unstable!Same anomaliesas seen in spectrumZoom in 1 for example*Colors indicates the currentpower spectrum (jet scale)

Conclusions1. An online MCM system can identify faults2. Coherence between phases can obtain immediateidentification whether the motor is normal orfaulty3. To discover all types of faults still need an expert inthe loop

Draft

TIME DOMAIN7-43-105 10HP 10ATIME DOMAINZOOM INFAULT: Noises from Load

7-43-105 10HP 10A cont.COHERENCE SPECTRUMNORMAL OPERATIONCOHERENCE SPECTRUMABNORMAL OPERATIONCorrelation between phasesin normal state and abnormal state

7-26-390 75kW 50A VSD cont.SPECTRUMCOHERENCEMechanical Assembly problemSpectrum and Correlation,Malfunction

Motor 3HPThe motor didn’t repaired well but with a small eccentricity