Joe geiman baker instruments 12 2006

On-line Motor Monitoring Joe Geiman Baker Instrument Co What are we really after? Induction motor and VFD applications    Reduce unscheduled downtime Indicates root cause analysis Save $ $ $ Motor Failure Areas: IEEE IEEE Study Study EPRI EPRI Study Study Bearing 44% Other 22% Bearing 41% Rotor 8% Stator 26% Other 14% Rotor 9% Stator 36% Motor Failure Causes: IEEE IEEE Study Study 100% 80% Electrical Fault Mechanical Breakage Insulation Breakdown Overheating 60% 40% 20% 0% Bearing Winding Safety and Connecting: Low Voltage (Less than 600V) Load Breaker Motor MCC Explorer Step one: Step two: Step three: Step four: Step five: Step six: Running motor STOP motor Connect Explorer Run and test STOP motor Disconnect Explorer Safety and Connecting: Medium and High Voltage (More than 600V) Load Breaker Motor CTs PTs Step one: Motor is running Step two: Connect Explorer CTs Step three: Connect Explorer PTs Explorer Acquire Data: Safe, Fast & Easy W/ EP-1 Breaker Motor CTs PTs EP Explorer of 700+ EPs at one customer First Energy RC Pump Power Quality Analysis  PQ Capabilities  Voltage and Current level, unbalance distortions  Kvars, KVA, KW’s, Power factor, Crest factor, Harmonic bar chart ect Motor Overheating    I2R Losses Motor Currents 100% rated Current 100% rated Temperature 110% rated Current 121% rated Temperature Motor Condition: Broken Rotorbar Fan hp 1740 rpm Motor Failure Areas: Bearings Bearings harm * BPFO * RPM Torque Spectra BPFO Controlled Lab Test … how it works Known Good Bearing Electrical Frequencies Removed Known Outer Race Defect Adding Electrical Electrical Frequencies Harmonic Removed Sidebands Marking * BPFO Signal Quality: harm * BPFO * RPM pole 5hp RMS Signal Noise Torque (Nm) 0.5 0.025 0.0012 Current (A) 0.0022 0.0005 Torque S/N = 4.8 * better Torque S/RMS = 125 * better “It can be found” “It is in your face” Eccentricity in Spectrum: • Location: • “1x” types: • • Current signals: Torque signals: ffund ± fmech fmech • - “Bar-pass” types: • • Current signals: Torque signals: n · fmech ± · ffund n · fmech (hopefully there) (many times not there) Eccentricity, Torque Signature: “1 x” location • 4-pole motor • 1x = just below 30Hz s 29.48 Hz  60  1768.8rpm Eccentricity, Current Signature: “1 x” location • 4-pole motor • 1x = just above 30Hz 60  30.58Hz  60 mins  1765.2rpm Eccentricity, Torque Signature: “Rotorbar Pass Frequency” location • 2-pole motor 2nd peak @ freq just below Harmonic • 1920Hz / 60Hz = 32bars (1920Hz is synchronous rotorbar pass frequency) 1916.56 Hz  59.89 Hz  f mech 32bars s 59.89 Hz  60  3593.5rpm Eccentricity, Current Signature: “Rotorbar Pass Frequency” location • 2-pole motor •1860Hz / 60Hz + = 32bars 1856.51Hz  60 Hz  59.89 Hz  f mech 32bars s 59.89 Hz  60  3593.5rpm “1x” locations # of Poles Synchronous [RPM] 10 12 3600 1800 1200 900 720 600 1% slip "1x" Torque "1x" Current [RPM] [Hz] [Hz] 3564 1782 1188 891 712.8 594 f1x elec  f fund  f mech 59.4 29.7 19.8 14.85 11.88 9.9 0.6 30.3 40.2 45.15 48.12 50.1 f1x trq  f mech Comparing Ieccent with Teccent • • • • Teccent at “expected” frequency Ieccent at “expected” frequency – 60Hz Teccent -28.43 dB relative amplitude Ieccent -34.9 dB relative amplitude Teccent is at the understandable location Teccent has a 4.5 times larger signal Demodulated Signals: Torque Torque vs vs Current Current Bad Motor #1 Bad Motor #2 Good Motor #1 Good Motor #2 Factor Demodulated Torque Demodulated Current 1* RPM 2* RPM 1* RPM 2* RPM 3.47E-05 7.94E-05 0.00324 0.03150 4.26E-05 7.96E-05 0.00398 0.03091 2.96E-05 1.35E-05 0.00245 0.03109 3.46E-05 1.42E-05 0.00308 0.03057 1.20 5.90 1.31 1.01 Conclusions: • Demodulated Current method does not agree with vibration’s methods • Demodulated Torque reacts like vibration’s methods • This method is independent of Motor design • This method does not disagree with IEEE motor scientist’s research Case Case study study II: II: Cooling Cooling tower tower fan fan and and gear gear signatures signatures Coal-fired Coal-fired power power plant plant Case Case study study II: II: Cooling Cooling tower tower fan fan and and gear gear signatures signatures Coal-fired Coal-fired power power plant plant Output Shaft Freq Intermediate Shaft Freq Blade Pass Freq Input Shaft Freq Case Case study study II: II: Cooling Cooling tower tower fan fan and and gear gear signatures signatures Coal-fired Coal-fired power power plant plant 2nd Mesh Frequency 1st Mesh Frequency Case Case study study II: II: Cooling Cooling tower tower fan fan and and gear gear signatures signatures Coal-fired Coal-fired power power plant plant SKF 22310c BPFI + - x Electrical BPFO + - x Electrical ... Connect Explorer CTs Step three: Connect Explorer PTs Explorer Acquire Data: Safe, Fast & Easy W/ EP-1 Breaker Motor CTs PTs EP Explorer of 700+ EPs at one customer First Energy RC Pump Power Quality... 59.76 59.64 59.52 59.4 59.28 59.16 59.04 58.92 58.8 Increasing Lines of Resolution: New Rotorbar y-axis Scale   signal  ' dB down' res.[dB]  10  log  fundamental   42mA   38.5dB  10