Bearing Fluting Specialists Stop the Attack at the source
 How Current Frequency Response detects Winding defects in Electric Motors.

How Current Frequency Response detects Winding defects in Electric Motors.

Sunday, April 16, 2023

Predictive Motor Winding Test

Traditionally Surge testing has been the dominant method for detecting winding defects in electric motors, but this test is well suited to a workshop environment as the instruments tend to be bench friendly.

An alternative which is Maintenance friendly (Portable) is the use of Current Frequency Response testing.

The Test is listed in the IEEE 1415:2006 as an effective method of determining winding condition.

The Current Frequency Response test injects a tone at a known voltage (Approximately 7 volts) into the winding and because this test is current determined the distance from the motor is relatively unlimited unlike surge testing. Therefore motor health can be measured from the Motor Control Cabinet many hundred of meters from the motor.

This explanation of the Test is a 3Phi Reliability perspective taken from many thousands of motor tests.

The standard test frequency of the I/F Current Frequency response is 200 hz, which stepped up to 400 hz in an alternating cycle.

This tone of 200 hz excites the motor winding between each Phase therefore, so one measurement per phase.

The protocol is to measure T1-T2, T1-T3, & T2-T3 in sequence.

The results are then compared and should be within specified limits. An imbalance above these limits indicates that a winding defect exists shown in a colour code within the MotorGenie App (free Download). Note: Red Alarm of the I/F (Current Frequency Response Imbalance)

Current Frequency Response Defect- Phase to Phase Short

Electrical theory states that Reactance of a coil is determined by XL = 2fL in Ohms

f frequency in Hz

L Inductance in Henry H

Reactance of a Capacitor is determined by XC = 1/2fC in Ohms

f frequency in Hz

C capacitance in F Farads

In a Motor Winding a minor amount of Reactance is generally Capacitance in the form of Insulation. XL tends to be the most dominant contributor to Impedance (Coil).

Parameters of Inductance

If you take XL = 2fL and you double the frequency, the relationship means the XL in Ohms doubles and therefore using V=I Z the current should halve if the voltage stays the same.

This is what the All TestPro instruments test for, the Voltage is known and the Frequency is doubled and the instrument measures the current in that change. Using current means testing can be conducted from the MCC (Unlimited Cable Length).

Using the XL= 2fL you would expect exactly 50% reduction in current if the frequency is doubled.

In practice this doesn’t happen as the Motor Winding has Capacitance which opposes XL therefore measurements of -15% to -50% are normal. Reading below -15% means Capacitance is high and test frequency needs to be adjusted upwards typically 400 hz to 800 hz.

Current Frequency Response -39% Test Frequency 400hz

The absolute reduction in current isn’t used but the imbalance between phases is very important.

If your readings are on the lower side -25% to -50% your winding is very inductive meaning any imbalance is likely to be Coil related as XL is dominant.

Under these measurements it is likely any imbalance is coming from a change in Inductance and hence a turn to turn short or Coil to coil short.

Higher I/F readings closer to -15% means Capacitance is relatively higher as the winding isn’t pure Inductance, any imbalance in these readings could be Insulation or Coil related. Therefore if the Phase Angle measurement are correlated an Insulation defect is developing.

If they are not correlated then the defect is likely to be Coil related and the motor decay rate is advanced. The explanation of Phase Angle is at https://www.3phi-reliability.com/blog/phase-angle-test-an-effective-means-of-determining-electric-motor-winding-health

Experience of 3Phi Reliability testing shows motors tend to develop a Phase Angle defect first as the insulation is stressed most likely from heat (Impedance Imbalance).

Phase Angle Phi 58 degrees

The I/F current frequency response then follows this initial Phase Angle defect with a coil defect to ultimate failure.

This can happen relatively quickly sometimes weeks.

Severe Turn to Turn Winding Defect

If an I/F Current Frequency response defect is detected and the Phase Angle test is Green (Pass) it is likely to be manufacturing defect which is less likely if the winding has been VPI (Vacuum Pressure Impregnation) which eliminates much of the air bubbles between winding strands.

VPI is a process which for critical motors adds a higher level of reliability, but is more expensive hence normally conducted on larger motors.

This VPI process is recommended in 3Phi Reliability Purchase & Overhaul specification for critical motors or elevated temperatures.

This explanation may seem quite complex, but taking measurements and entering the data into the MotorGenie App (free download) is simple as the App calculates the imbalance and applies the correct limits giving you a Pass (Green), Warning (Yellow) or Alarm (Red) for the Motor Winding.

This method is quite rapid taking only a few minutes for a complete Motor Test, and because of the portability can be conducted in some challenging locations eg elevated motor bases, platforms, or pits.

The procedure is to start at the MCC cabinet and if a defect is detected then move to the motor, therefore not all motor terminal boxes need to be opened. Our experience suggests that it is wise to conduct testing at the motor for the first survey as many resistive defects are common across all phases, therefore imbalances are less dominant.

Note: Severe Resistance imbalances above 5% also result in Voltage drops to the motor greatly affecting Reliability & Energy Efficiency.

High Resistance defect stresses winding

3Phi Reliability calculate the As Found versus As Left resistances and the I^2R loss or Power savings can be quantified. Termination guidelines are provided to all clients.

This Electrical Preventative Maintenance therefore “Gains Electric Motor Reliability & Returns Energy Savings”

www.3Phi-reliability.com

Best Practice Motor Management

Francky
wrote
Tuesday, July 25, 2023, 07:48
Thank you for this informative article on Electric Motors

Blog  Free Advice on Electric Motor Reliability and Energy Savings


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Most of clients make gains on the every first day of implementation. Best Practice Motor Management has a short Return on Investment, improving Electric Motor Reliability and Energy Savings are immediate.
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Based on a large field dataset from 3Phi Reliability showing how impedance imbalance and poor terminations affect motor life and performance. ", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/how-to-gain-electric-motor-reliability-with-two-initiatives", "image": "https://www.3phi-reliability.com/images/blog/motor-reliability-two-initiatives.jpg", "datePublished": "2023-04-23", "dateModified": "2023-04-23", "keywords": [ "electric motor reliability", "motor acceptance testing", "motor installation best practice", "impedance imbalance", "motor termination quality", "motor circuit analysis", "preventive maintenance", "motor energy efficiency", "AllTestPro", "motor reliability initiatives", "industrial motor maintenance", "motor purchase specification" ], "articleSection": "Motor Reliability & Maintenance" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/how-current-frequency-response-detects-winding-defects-in-electric-motors" }, "headline": "How Current Frequency Response detects Winding defects in Electric Motors", "description": "Explains how Current Frequency Response (C/F) testing — a low‑voltage, maintenance‑friendly method defined in IEEE 1415 — can detect winding defects in motors by injecting a tone into the winding and comparing current responses across phases to identify coil or insulation faults from anywhere in the circuit.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/how-current-frequency-response-detects-winding-defects-in-electric-motors", "image": "https://www.3phi-reliability.com/images/blog/current-frequency-response-winding-defects.jpg", "datePublished": "2023-04-16", "dateModified": "2023-04-16", "keywords": [ "current frequency response", "motor winding defects", "electric motor testing", "motor reliability", "MCA", "winding fault detection", "AllTestPro", "preventive maintenance", "phase imbalance detection", "industrial motors", "motor condition monitoring" ], "articleSection": "Motor Testing & Diagnostics" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/impedance-imbalance-in-an-electric-motor-wastes-energy" }, "headline": "Impedance Imbalance in an Electric Motor wastes Energy", "description": "Explains how impedance imbalance in an electric motor — due to mismatched reactance or winding/rotor/circuit defects — causes inefficient current draw, heat losses, reduced efficiency and shortened motor life. The article highlights how even motors with high efficiency classes can waste energy if impedance imbalance is not addressed.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/impedance-imbalance-in-an-electric-motor-wastes-energy", "image": "https://www.3phi-reliability.com/images/blog/impedance-imbalance-energy-waste.jpg", "datePublished": "2023-04-15", "dateModified": "2023-04-15", "keywords": [ "impedance imbalance", "electric motor inefficiency", "motor energy waste", "motor losses", "motor reliability", "motor circuit analysis", "induction motor testing", "reactance imbalance", "winding defects", "rotor defects", "preventive maintenance", "industrial motors" ], "articleSection": "Motor Efficiency & Reliability" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/changing-motors-from-iec2-to-iec3-or-iec-4-does-it-pay-back" }, "headline": "Changing Motors from IEC2 to IEC3, or IEC 4, does it Pay Back?", "description": "Analysis of the potential energy‑cost savings and payback period when replacing older IEC2‑class motors with higher‑efficiency IEC3 or IEC4 motors — compared to alternative strategies such as electrical preventive maintenance to correct circuit/wiring issues.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/changing-motors-from-iec2-to-iec3-or-iec-4-does-it-pay-back", "image": "https://www.3phi-reliability.com/images/blog/iec2-to-iec3-iec4-payback.jpg", "datePublished": "2022-12-20", "dateModified": "2022-12-20", "keywords": [ "IEC2 motor", "IEC3 motor", "IEC4 motor", "motor energy efficiency", "motor replacement payback", "electric motor operating cost", "industrial motors", "energy savings", "motor maintenance strategy", "electric motor reliability", "motor circuit maintenance", "preventive maintenance" ], "articleSection": "Motor Efficiency & Energy Savings" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/how-common-mode-voltages-bearing-currents-are-created-part-one" }, "headline": "How Common Mode Voltages (Bearing Currents) are created, Part One", "description": "Explains how common‑mode voltages produced by inverter (VFD) drives can generate high‑frequency common‑mode currents that flow through motor windings, shafts, and bearings — leading to bearing fluting, insulation damage and reduced motor reliability if grounding, cable screening or mitigation measures are not properly applied.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/how-common-mode-voltages-bearing-currents-are-created-part-one", "image": "https://www.3phi-reliability.com/images/blog/common-mode-voltage-bearing-currents.jpg", "datePublished": "2022-12-08", "dateModified": "2022-12-08", "keywords": [ "common mode voltage", "bearing currents", "inverter driven motors", "motor reliability", "bearing fluting", "electric motor maintenance", "VFD motor protection", "motor insulation damage", "EMF cores", "shaft voltage", "motor grounding", "industrial motors" ], "articleSection": "Bearing Currents & Motor Protection" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/the-number-one-ranked-electrical-preventative-maintenance-task-to-save-energy-and-stop-bearing-currents" }, "headline": "The number one ranked Electrical Preventative Maintenance Task to Save Energy and Stop Bearing Currents.", "description": "Explains why checking and maintaining the MEN (Multiple Earth Neutral) link — ensuring a low‑resistance neutral‑to‑earth bond and balanced 3‑phase supply — is considered the top electrical preventive maintenance task. Proper MEN link maintenance prevents supply imbalance, reduces common‑mode voltage from VFDs, decreases energy losses, and mitigates bearing current risk for electric motors.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/the-number-one-ranked-electrical-preventative-maintenance-task-to-save-energy-and-stop-bearing-currents", "image": "https://www.3phi-reliability.com/images/blog/men-link-maintenance.jpg", "datePublished": "2022-12-05", "dateModified": "2022-12-05", "keywords": [ "MEN link", "neutral to earth bond", "electrical preventative maintenance", "motor energy efficiency", "bearing currents mitigation", "motor reliability", "variable frequency drive", "common mode voltage", "power quality", "industrial motor maintenance", "energy savings", "supply imbalance prevention" ], "articleSection": "Motor Protection & Maintenance" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/extraction-fan-1924-gbp-per-annum-energy-savings" }, "headline": "Extraction Fan, 1924 GBP per Annum Energy Savings", "description": "Case study showing how optimising or replacing an extraction fan system can yield significant energy savings (approx. £1,924 per year), by reducing unnecessary running time and improving system efficiency — highlighting cost-effective maintenance for HVAC and ventilation systems.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/extraction-fan-1924-gbp-per-annum-energy-savings", "image": "https://www.3phi-reliability.com/images/blog/extraction-fan-energy-saving.jpg", "datePublished": "2022-12-05", "dateModified": "2022-12-05", "keywords": [ "extraction fan", "energy savings", "ventilation fan efficiency", "industrial ventilation", "fan maintenance", "HVAC energy efficiency", "electric fan energy use", "preventive maintenance", "ventilation system cost savings", "motor efficiency", "fan operating cost" ], "articleSection": "Energy Efficiency & Ventilation" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/why-high-frequency-drive-emissions-are-deadly-for-electric-motor-insulation" }, "headline": "Why High Frequency Drive Emissions are Deadly for Electric Motor Insulation", "description": "Explains how high-frequency emissions from VFD/inverter drives can degrade motor insulation and shorten motor life — highlighting the effects of high switching frequency, capacitive coupling, skin-effect, bearing currents and insulation stress under PWM supply.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/why-high-frequency-drive-emissions-are-deadly-for-electric-motor-insulation", "image": "https://www.3phi-reliability.com/images/blog/high-frequency-drive-insulation-issue.jpg", "datePublished": "2022-10-30", "dateModified": "2022-10-30", "keywords": [ "high frequency drive emissions", "VFD motor insulation damage", "inverter driven motor risks", "common mode voltage", "bearing currents", "motor insulation degradation", "electric motor maintenance", "PWM drive effects", "motor reliability", "insulation stress", "industrial motors", "preventive maintenance" ], "articleSection": "Motor Protection & Reliability" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/phase-angle-test-an-effective-means-of-determining-electric-motor-winding-health" }, "headline": "Phase Angle Test an Effective Means of Determining Electric Motor Winding Health", "description": "Details how the phase angle test — a de-energized, low-voltage method listed in IEEE 1415:2006 — can be used to assess the health of an electric motor’s winding by detecting early changes in inductance, capacitance or insulation, often before traditional tests show abnormalities.", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/phase-angle-test-an-effective-means-of-determining-electric-motor-winding-health", "image": "https://www.3phi-reliability.com/images/blog/phase-angle-test-motor-winding-health.jpg", "datePublished": "2022-10-23", "dateModified": "2022-10-23", "keywords": [ "phase angle test", "motor winding health", "electric motor testing", "motor circuit analysis", "inductance test", "winding insulation condition", "industrial motor maintenance", "predictive maintenance", "motor reliability", "IEEE 1415", "motor preventive maintenance" ], "articleSection": "Motor Testing & Diagnostics" } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/common-defect-in-air-compressors-with-star-delta-starters" }, "headline": "Common Defect in Air Compressors with Star Delta Starters", "description": "Discussion of frequent high-resistance and connection defects in air compressors using Star-Delta starters, leading to motor insulation decay and reduced service life if not maintained properly.", "datePublished": "2022-09-26", "dateModified": "2022-09-26", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/common-defect-in-air-compressors-with-star-delta-starters", "image": "https://www.3phi-reliability.com/blog/common-defect-in-air-compressors-with-star-delta-starters", "keywords": [ "air compressors", "star delta starter", "Star-Delta", "motor winding defects", "high resistance defects", "motor insulation decay", "electric motor preventive maintenance", "motor testing", "compressor reliability", "energy savings" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/bearing-currents-on-motor-drive-units" }, "headline": "Bearing Currents on Motor Drive Units", "description": "Discussion of how high-frequency currents from variable-frequency drives (VFDs) can cause bearing fluting, insulation issues and bearing failures — and how fitting EMF cores can suppress these bearing currents effectively.", "datePublished": "2022-09-25", "dateModified": "2022-09-25", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/bearing-currents-on-motor-drive-units", "image": "https://www.3phi-reliability.com/blog/bearing-currents-on-motor-drive-units", "keywords": [ "bearing currents", "motor drive units", "variable frequency drive", "VFD", "EMF cores", "bearing fluting", "motor reliability", "electric motor maintenance", "common mode voltage", "shaft currents" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/variable-speed-drive-preventative-maintenance" }, "headline": "Variable Speed Drive Preventative Maintenance", "description": "Procedure to test Rectifier & Converter of Variable Speed Drives (VFDs) to detect diode or component defects before functional failure — reducing common mode currents, bearing currents and improving long-term motor reliability.", "datePublished": "2022-08-28", "dateModified": "2022-08-28", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/variable-speed-drive-preventative-maintenance", "image": "https://www.3phi-reliability.com/blog/variable-speed-drive-preventative-maintenance", "keywords": [ "variable speed drive", "VFD", "preventative maintenance", "rectifier test", "diode test", "motor reliability", "bearing currents", "common mode current", "electrical maintenance", "drive servicing" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/what-are-the-methods-of-testing-an-electric-motor" }, "headline": "What are the Methods of Testing an Electric Motor", "description": "Comprehensive overview of the accepted test methods (from IEEE Std 1415-2006) for assessing electric motor health: insulation resistance, dielectric/dissipation factor, winding resistance, surge test, partial discharge, current/voltage analyses, vibration, thermography, oil/grease analysis, and other condition-based techniques recommended by 3Phi Reliability.", "datePublished": "2022-08-14", "dateModified": "2022-08-14", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/what-are-the-methods-of-testing-an-electric-motor", "image": "https://www.3phi-reliability.com/blog/what-are-the-methods-of-testing-an-electric-motor", "keywords": [ "electric motor testing", "motor testing methods", "insulation resistance", "dissipation factor", "winding resistance", "surge test", "partial discharge", "vibration analysis", "thermography", "motor maintenance", "motor condition monitoring" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/financial-justification-of-motor-replacement" }, "headline": "Financial Justification of Motor Replacement", "description": "Explains how inefficiencies and impedance imbalance in electric motors can lead to increased energy costs and reduced reliability — showing how a motor test and financial calculation (using the 3Phi Energy Calculator) can justify replacement, with fast payback and gains in energy savings and uptime.", "datePublished": "2022-08-13", "dateModified": "2022-08-13", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/financial-justification-of-motor-replacement", "image": "https://www.3phi-reliability.com/blog/financial-justification-of-motor-replacement", "keywords": [ "motor replacement", "electric motor inefficiency", "impedance imbalance", "energy savings", "motor reliability", "cost justification", "life-cycle cost", "energy efficiency", "electric motor maintenance", "return on investment" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/checklist-for-implementing-an-electrical-preventative-maintenance-program-electric-motor-testing" }, "headline": "Checklist for Implementing an Electrical Preventative Maintenance Program (Electric Motor Testing)", "description": "Guide to implementing an electrical preventative maintenance program focused on electric motor testing: covering people & process engagement, proper tooling, realistic scope, visual and electrical checks (resistance/impedance, insulation, wiring, terminations, grounding), regular scheduling, and avoiding reactive‑maintenance pitfalls.", "datePublished": "2022-08-09", "dateModified": "2022-08-09", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/checklist-for-implementing-an-electrical-preventative-maintenance-program-electric-motor-testing", "image": "https://www.3phi-reliability.com/blog/checklist-for-implementing-an-electrical-preventative-maintenance-program-electric-motor-testing", "keywords": [ "electrical preventative maintenance", "motor testing", "electric motor maintenance", "preventative maintenance checklist", "motor reliability", "insulation testing", "resistance testing", "impedance testing", "maintenance program implementation", "asset management" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/electric-motors-failures" }, "headline": "Electric Motors Failures", "description": "Overview of common failure modes in electric motors — including data from studies showing motor bearing and winding defects, especially on motors connected to variable‑speed drives — and recommendations for electrical maintenance programmes and motor circuit analysis to detect defects early.", "datePublished": "2023-07-24", "dateModified": "2023-07-24", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/electric-motors-failures", "image": "https://www.3phi-reliability.com/blog/electric-motors-failures", "keywords": [ "electric motors failures", "motor defects", "bearing defects", "winding defects", "variable speed drive motors", "motor reliability", "motor circuit analysis", "preventive maintenance", "drive related failures", "industrial motor maintenance" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } } { "@context": "https://schema.org", "@type": "BlogPosting", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://www.3phi-reliability.com/blog/stop-bearing-fluting-currents-at-the-source" }, "headline": "Stop Bearing Fluting Currents at the Source", "description": "Explains how high‑frequency bearing currents from variable‑speed drives (VFDs) cause bearing fluting, insulation and lubrication damage — and how proper grounding plus installation of EMF cores effectively reduces harmful currents by over 99%, protecting motor bearings, lubrication and insulation.", "datePublished": "2022-08-06", "dateModified": "2022-08-06", "author": { "@type": "Organization", "name": "3Phi Reliability" }, "publisher": { "@type": "Organization", "name": "3Phi Reliability", "logo": { "@type": "ImageObject", "url": "https://www.3phi-reliability.com/images/logo.png" } }, "url": "https://www.3phi-reliability.com/blog/stop-bearing-fluting-currents-at-the-source", "image": "https://www.3phi-reliability.com/blog/stop-bearing-fluting-currents-at-the-source", "keywords": [ "bearing fluting", "bearing currents", "variable speed drive", "VFD", "EMF cores", "motor insulation", "motor lubrication", "motor reliability", "electrical grounding", "industrial motor maintenance" ], "articleSection": "Motor Reliability & Maintenance", "speakable": { "@type": "SpeakableSpecification", "xpath": [ "/html/head/title", "//h1", "//p" ] } }
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