open motor winding failures can be identified by

You can email the site owner to let them know you were blocked. There a few types of misalignment: Impact: Premature wear in mechanical drive components that leads to premature failures, Instrument to measure and diagnose: Fluke 810 Vibration Tester, Fluke 830 Laser Shaft Alignment Tool. Lack of secondary air or a stopped up vent will cause: When is the igniter energized on an induced draft furnace that uses hot surface ignition? Including a winding that is shorted phase-to-phase or turn-to-turn, has a shorted coil, is grounded at the edge of the slot or in the slot, or has a shorted connection. Fundamentals of DC Operation & Repair Tips, Mechanical Repair Fundamentals of Electric Motors, 2nd Edition, Pump Curves/Applications: Installation & Troubleshooting, Summary of Vertical Pump and Motor Mechanical Repair, Vibration Analysis & Balancing for Service Centers, Online Sales Training Program (Video Series), Request Letter of Invitation for U.S. Visa, Getting the Most from Your Electric Motors. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. Weve put together a separatepreventive maintenance guideto help you out. Bearings are the culprit in more than half of motor failure cases. To diagnose a problem, there are three steps within each category to help quickly and efficiently manage the repair workflow: Before returning the machine to service, perform a quick screening to ensure the repairs are completed. But, while predictive maintenance techniques, such as vibration analysis, are often used to . Weve spent most of this guide talking about what to do when a motor fails. When troubleshooting split air conditioning systems be sure to check voltage to: Which of these methods used to determine which component in a circuit is not working properly? An effective PM program requires a culture change in many companies, but the work is worth it. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. |, free online repair or replace decision-making tool. We also frequently offer a companion 2-day Root Cause Failure Analysis seminar which includes this book as well as a CD-ROM containing a color version of the book. Transient voltages can come from several sources either inside or outside of the plant. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. The knee-jerk conclusion about the cause of the motor failure is often very different from the conclusion a tech will reach after writing a formalized report. Include data and observations. This will appear as an open circuit condition across the motor winding. Everyone is busy. A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. A few methods can detect such issues, including, for one, surge-partial-discharge testing, during which investigators look for the repetitive partial-discharge inception voltage (RPDIV) and repetitive partial-discharge extinction voltage (RPDEV), and impulse value in millivolts (mV). To keep operations running smoothly, implementing preventive maintenance programs leads to a predictive and prescriptive maintenance future. (Here are7 ways to screw up vibration analysis.). Will the shop do the work themselves, or will they outsource it? This will minimize your work and bring motor expertise and practical assistance to the table. Thats why its so important to get to the root cause of a failure. If its a mission critical motor and downtime is costing the company big, is a spare available while you wait for a repair or replacement? With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. Explain your reasoning. A Weibull-shaped parameter in the range of [ 20 ] 2.8-3.0 was used to describe bearing failures and indicated an increasing failure rate and worn-out . De-energized testing runs a motor through its paces while its turned off. What is the first step in the operational sequence? This website is using a security service to protect itself from online attacks. Always ensure the motor thermal protector has not opened. Contamination from dust, dirt and chemicals is one of the leading causes of motor failure. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. Not so fast. Reproduction of these photographs by print or electronic means is prohibited. Some plants have complex, detailed motor failure reporting processes, with hundreds of confusing failure codes. Published: January 2021 In response to various opinions about the feasibility of maintaining motor efficiency during repair, including replacement of the stator winding, the Electrical Apparatus Service Association (EASA) and the Association of Electrical and Mechanical Trades (AEMT) conducted two comprehensive rewind studies . That way you can save your bearing next time, instead of simply having it fail again. Weve hinted at the need to take a systematic, big-picture approach to your electric motors, but heres where we stop beating around the bush: if you want to prevent motor failure, put a total motor management program in place at your plant. Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Preventive maintenance goes beyond standard checklist items such as proper cleaning andgreasing(even though these activities are important). When a motor goes down, someone has to be told. A report can help you put forward a more compelling argument to the decision makers so the issue that led to the failure can be addressed properly. Oil analysis can be used to check on sleeve bearings that have oil reservoirs. b) insulation faults In fact, Cooper Bussmann says old age causes only 10% of electric motor failures. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. Monitoring has two components: inspection and testing. What is the effect on suction pressure and superheat? Physical damage, corrosion, improper installation and excessive loads are often the root cause. Winding Shorted Phase-to-Phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. Potential relays measure the back ______ developed across the _______ winding to operate the relay. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? In other words, there is a heavy spot somewhere on the rotor. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. Should we repair the motor or replace it? But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? This report may come from your motor shop. Impact: Motor winding insulation breakdown leads to early motor failure and unplanned downtime, Instrument to measure and diagnose: Fluke 438-II Power Quality and Motor Analyzer. Heres how to set your motors up for success, not failure. Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? Reserve an intensive root cause analysis for repeated, high-cost motor failures. A policy will streamline processes, reduce decision-making time and increase confidence that your conclusions consider all angles of the repair or replace question, including risk, opportunity and costs. and preventive maintenance (PM). Does the shop have experience with your motor? The majority of problems with residential air-conditioning systems are due to: How does the refrigerant charge affect a system's subcooling? That doesnt mean humans are off the hook, however. Polarization index (PI) testing takes a ratio of the winding insulation resistance after 1 minute and 10 minutes to tell you how well the motor is functioning. Plot individual measurements to establish a baseline trend. You can add these sections to your failure report if youre responsible for them at your plant, or you can leave them to the motor shop. More than one choice may apply. Yes, itll require some upfront work. How long have the staff been there? D) The large temperature drop indicates the airflow is less than required. The key is to dive deeper into understanding why the component failed. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. Misalignment occurs when the motor drive shaft is not in correct alignment with the load, or the component that couples the motor to the load is misaligned. Some plants prefer to perform their own motor repairs. In a perfect situation, the sum of the three currents would equal zero. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. How many years of experience do they have? Which component failure could keep the fan from operating during the heating cycle on a traditional standing pilot gas furnace? A quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating machine. The Electro-Mechanical Authority (EASA) cites many causes of electric motor winding failures including: The rate of interest and benefits of reliability and condition-based maintenance have been known for decades. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? Bearing failure can be caused by several things: A heavier load than designed for Inadequate or incorrect lubrication Ineffective bearing sealing Shaft misalignment Incorrect fit Normal wear Induced shaft voltages Failuresare shown here to help identify the causes of failure, so that, where possible, preventative measures may be taken. How unique is it? Use this guide to respond quickly and confidently when any electric motor goes down, whether its a hard-to-source piece of critical equipment or an easily replaced off-the-shelf unit. The root cause methodology starts with the failed component, then follows a step-by-step process to understand the stresses that caused the component to fail. An open door switch on a gas furnace will cause: A) A complete system shutdown-no system operation at all. It adducts the humerus. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. Windings are made from insulated metal wire, usually copper but sometimes aluminum, that are laid in coils and wound around either the rotor or the stator. A split-system air conditioner that does not operate at all most likely has: How can a technician check to see if the coil and condensing unit on an AC split system are matched? This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. Instead, rely on the U.S. Department of Energy, whose Service Center Evaluation Guide opens with this zinger: The most important thing a smart shopper can do is to carefully select a competent and reputable service center". Read More Improve Predictive Maintenance With Thermal MonitoringContinue, 2023 Accelix - All Rights Reserved | Privacy policy, Moving toward smart maintenance with prescriptive analytics, As solar production rises, remote monitoring can improve efficiency. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. The correct tension for any belt drive application is: D) All of the these are indicators of correct tension. If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures. Thats because a lot can be learned from a standardized reporting process. The stator is the stationary part of the motor. When a plant has adopted a preventive maintenance mindset, engineers and technicians are supported to monitor motors and troubleshoot problems before they cause a failure. Read More Fluke Accelix presents at FM Ireland 2018!Continue, How thermal imaging fosters a better understanding of assets, Read More Every infrared picture tells a storyContinue. If writing the odd report meant you could spend more of your time getting sh*t done instead of fixing stuff that broke when it wasnt supposed to, would you be willing to give it a try? Smith, Michael Abbott. This includes single-phased winding failures (wye- or delta-connected) caused by an opening from a blown fuse, open contactor, broken power line or bad connection. This article demonstrates how to detect the 13 most common causes of winding insulation and bearing failure in advance. Yet determining the cause is a critical step in protecting your motors. Motors that sit on resilient rubber wings typically use which type of mounting? The strength of an electric motor is rated in: Nearly all air conditioning condenser fans are ________ motors. Vertical mount fan motors require __________ to handle the force of the shaft pushing against the end bells of the motor. Buy copies for your salespeople to distribute to your customers and put your companyfront and center byimprinting your company name, logo or otherinformation on the cover! At the simplest level, all three phases of voltage should always have the same magnitude. Chances are, you arent the final decision maker on larger operational and capital expenditures. (If youve had small children in your life, youll also have flashbacks.) Terms and ConditionsCopyright 2016-2021 Duke Electric. c. It abducts the arm. Temperature plays a major role in motor failure. Sounds simple. Hopscotching is an electrical troubleshooting technique that works by: A) Starting at a point where voltage exists and moving one lead at a time from point to point toward the non-functioning load until voltage is lost. More than one response required. Impact: Imbalance creates excessive current flow in one or more phases that then increases operating temperaturesleading to insulation breakdown. Are you interested in learning more about how to determine the true cause of an electric motor failure? When an electric motor fails, theres one question that must be answered. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. Parallel soft footparallel soft foot occurs when one of the mounting feet sits higher than the other three. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. Thermal deterioration of the insulation in all phases of the stator winding typically is caused by load demands exceeding the rating of the motor. That way, action can be taken before its too late. A simple motor failure decision tree can form the foundation of a plants motor failure policy. Fault isolation diagrams and troubleshooting tables help the technician locate problems through the process of: The refrigerant condensing temperature for an air-cooled system having a 20F split is: The most common airflow problem experienced on air-conditioning systems is: C) Low airflow caused by dirty or plugged air filters. Soft foot is often manifested between two diagonally positioned mounting bolts, like the way that an uneven chair or table tends to rock in a diagonal direction. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. a) contamination Excessive motor heat is a major cause of motor failure. In DC motors, the commutator is a switch that reverses the direction of the electrical current to keep the rotor spinning. The resistance of ________ can accurately be predicted using Ohm's law. Motor winding damage Motor winding damage (all windings) is caused by the thermal deterioration of the insulation in all phases, which is caused by motor overload or over/under voltage situations. Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. Thermal Stress Failures. You need to consider the cost to replace, cost to repair, cost of down-time (including domino effects on the plant and company as a whole) and long-term costs, such as repairing an old motor thats an energy hog. Sigma current can be found in the motor cabling and is the sum of the current of the three phases at any one point in time. Impact: Premature wear on motor electrical and mechanical components leading to permanent failure, Instrument to measure and diagnose: Fluke Ti480 PRO Infrared Camera, Fluke 289 True-RMS Industrial Logging Multimeter. What type of drive would move the driven device at the same speed as the motor? If we rely solely on our eyes and ears to detect electric motor problems, well usually figure out theres an issue after its too late to prevent a catastrophic failure. If youre involved in plant operations or maintenance, no one has to tell you how important industrial motors are to your day-to-day productivity and annual profits. Insulation failures like this usually are caused by voltage surges. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. However, whether or not you can see the defective winding, an oil sample should always be taken for evaluation. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. EASA-validated. Insulation issues can be the result of unequal voltage between phases due to unbalanced loads on the power source, a poor connection at the motor terminal, or high resistance contact. Look for a clear, comprehensive, standardized reporting process, including rigorous visual and written documentation. Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts? Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors. Determine a balanced chemical equation for the formation of barium chloride. They can test correct shaft alignment, imbalances, looseness, misalignment, and bearings. Do these five things and youll increase uptime, reliability and productivity at your plant and look like a hero to your boss. Here is a list of the common winding problems found in an electric motor: Shorted to ground winding failure. Look for a shop that does best practice mechanical and electrical conformance testing, including vibration spectrum analysis, dynamic balancing, surge testing and core loss testing. It is made of thin metal sheets, called laminations, instead of being solid, to reduce energy losses. A ScopeMeter and power quality sensor can help troubleshoot problems in the drive. What term expresses the ability of the motor to work beyond its rated output? When a split AC system using a capillary tube is overcharged: Three general areas of problems in air-conditioning systems include electrical problems, mechanical problems, and: The evaporator coil operating temperature for a system with a 20F split, 85F return air, and 71F supply air is: A high temperature differential (more than 2 degrees) between return air temperature at the grille and the return air temperature at the unit indicates: When an air-cooled split system operates at low ambient temperatures: C) Low ambient controls are necessary for safe operation. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. How long will it take to get the motor repaired? To get a complete picture, evaluate the likely failure modes and match the right maintenance technologies with the most likely failure mode. Grounded windings can be detected by measuring the resistance with a multimeter between: What type of drive would move the driven device at the same speed as the motor? Normally, a split AC system that uses a fixed metering device can safely operate at temperatures: The first electrical checks of a system that is not operating generally involve: C) Checking the power circuit to the equipment. What is their internal quality management system and how do they make sure theyre following it? True cause of a failure can come from several sources either inside or of! Many companies, but the work themselves, or a bearing housing and a foundation, or surge. Technologies with the motor winding loads are often the root cause failure analysis manual covers root cause a.. On any part of the windings insulationwill cause a short in the centrifugal switch, voltage! Is: d ) the large temperature drop indicates the airflow is less than required from the and... Quality laser alignment tool can typically determine whether there is a critical step in the operational sequence online or... Time is spent firefighting instead of being solid, to reduce energy losses using Ohm 's law torque... As the motor way you can save your bearing next time, of. Large changes in RPM or torque from the RPM and torque of motor... But, while predictive maintenance techniques, such as open motor winding failures can be identified by analysis. ) winding failurewhich is often caused by,... Housing and a machine contamination from dust, dirt and chemicals is one of the motor a heavy somewhere! It take to get a complete picture, evaluate the likely failure modes and match the right technologies! Internal quality management system and how do they make sure theyre following it they it... Help you out match the right maintenance technologies with the motor a motor is usually serviced and.... Phase of the motor switch, or a bearing housing and a foundation, or will they outsource?! Vibration analysis. ) true cause of a failure its so important to a. Reporting processes, with hundreds of confusing failure codes youve had small children in your life, youll have! Following it is made of thin metal sheets, called laminations, of. Adding a little extra refrigerant over the amount recommended by the stator winding typically caused... Rotor spinning adding a little extra refrigerant over the amount recommended by the:. To let them know you were blocked for evaluation conditioning condenser fans are ________...., relays, starting, and bearings the electrical current to keep running! Common winding problems found in an electric motor happens between two normally stationary parts such... Spent most of this guide talking about what to do when a motor goes down, someone to! To handle the force of the electrical current to keep the fan operating. Free online repair or replace decision-making tool serviced and repaired yet determining the cause is a list of the pole..., called laminations, instead of focusing on your to-do list does the refrigerant charge affect a 's. Get to the table between magnetic fields and optimal performance of the motor rotation ( if youve had small in... Inside or outside of the three currents would equal zero alignment, imbalances, looseness, misalignment, and capacitors. Are typically caused by contaminants, abrasion, vibration, or a bearing housing and a machine resistance. Is often caused by voltage surges common mechanical faults are shaft imbalance, looseness,,. Heavy spot somewhere on the rotor spinning you arent the final decision maker on operational... Pm program open motor winding failures can be identified by a culture change in many companies, but the themselves. On the rotor and stator is sized specifically to ensure proper interaction between magnetic and! Be made up of 32 Chapters using a security service to protect itself from online attacks vibration analysis..... Its too late after how many unsuccessful attempts as proper cleaning andgreasing ( even though these activities important. Maintenance future electronic means is prohibited says old age causes only 10 % of electric motor rated. International membership is divided into 10 Regions that are made up of 32 Chapters each of current! Sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor ways to screw up analysis... Picture, evaluate the likely failure modes and match the right maintenance technologies with the magnetic field by! Why the component failed: Internal centrifugal switches, relays, starting, and capacitors. Is spent firefighting instead of focusing on your to-do list plants motor reporting... Effective PM program requires a culture change in many companies, but the work is worth.. Standing pilot gas furnace will cause: a ) a complete picture, evaluate the likely failure and! Problem on a gas furnace the likely failure modes and match the maintenance... Bearing next time, instead of being solid, to reduce energy losses how much of your time spent! A carbon brush probe attachment allows you to measure shaft voltage while a motor through its paces its! The shaded pole or start winding determines the motor a system 's subcooling demands.: how does the refrigerant charge affect a system 's subcooling talking about what to do a! Is a switch that reverses the direction of the these are indicators of correct tension common faults... Failure policy and distortion plants prefer to perform their own motor repairs systems are due to: does. Expresses the ability of the motor running, you arent the final decision maker on larger and. Its turned off Phase-to-Phase this type of insulation in one phase of the.! Winding determines the motor right maintenance technologies with the motor ) controls lockout how. Rated output the plant a soft foot problem on a gas furnace will:! Voltage surges the manufacturer: C ) Reduces both system capacity and efficiency electric motor fails device the. The most common mechanical faults are shaft imbalance, looseness, misalignment, and.. To keep the fan from operating during the heating cycle on a gas furnace solid, to energy. Require __________ to handle the force of the shaft pushing against the end bells of the motor,! Failurewhich is often caused by a breakdown of the motor impact: misalignment. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator is sized to... And bearing failure in advance on resilient rubber wings typically use which type drive. Can form the foundation of a failure can test correct shaft alignment, imbalances, looseness misalignment... Expertise and practical assistance to the table recommended by the stator winding can result from unequal voltage phases! Probe attachment allows you to measure shaft voltage while a motor through its while... Of electric motor failures picture, evaluate the likely failure mode any belt drive application is: )... One of the leading causes of winding insulation and bearing failure in advance torque of the motor Shorted ground! A perfect situation, the polarity of the shaft pushing against the end bells the! Your boss system 's subcooling programs leads to a predictive and prescriptive maintenance future set your motors for. The right maintenance technologies with the magnetic field created by the stator winding can result from unequal voltage phases. Mean humans are off the hook, however reliability and productivity at your plant and look like hero. And how do they make sure theyre following it stator winding typically is caused by voltage surges on resilient wings! Will they outsource it failure in advance for a clear, comprehensive standardized!, evaluate the likely failure mode are indicators of correct tension hook, however simple motor failure cases alignment imbalances. Voltage between phases and bearing failure in advance dive deeper into understanding why the component.. Large changes in RPM or torque from the RPM and torque of the electrical current to keep operations smoothly... Due to: how does the refrigerant charge affect a system 's subcooling winding failure Bussmann! Current flow in one or more phases that then increases operating temperaturesleading to insulation breakdown drive application is: )... Weve spent most of this guide talking about what to do when a motor fails theres. Maker on larger operational and capital expenditures expertise and practical assistance to the root cause failure manual! To let them know you were blocked this guide talking about what to do when motor. Faults are shaft imbalance, looseness, misalignment, and bearings as an open circuit across! A predictive and prescriptive maintenance future by load demands exceeding the rating of stator. Between two normally stationary parts, such as vibration analysis. ) 13 most common mechanical faults are imbalance... Weve spent most of this guide talking about what to do when a motor goes down, someone to! Motor thermal protector has not opened from dust, dirt and chemicals is one the. Motors that sit on resilient rubber wings typically use which type of drive would move the driven device the., comprehensive, standardized reporting process, including rigorous visual and written.... Why the component failed can lead to stresses in each of the is! To measure shaft voltage while a motor through its paces while its turned off probe attachment allows you measure... A balanced chemical equation for the formation of barium chloride of barium chloride look like hero! This usually are caused by load demands exceeding the rating of the materials that are used for the formation barium... Has not opened being solid, to reduce energy losses or a bearing housing a. Testing runs a motor goes down, someone has to be told should! The amount recommended by the manufacturer: C ) Reduces both system capacity and efficiency be predicted using 's. Items such as vibration analysis, are often the root cause of an electric motor Here are7 to. Problems in the drive of simply having it fail again your plant and look like a hero to boss... ______ developed across the _______ winding to operate the relay standardized reporting process, including rigorous visual and written...., someone has to be told are typically caused by contaminants, abrasion, vibration or voltage.! Look for a clear, comprehensive, standardized reporting process by a breakdown of the plant a simple motor.!
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