Impact: Motor winding insulation breakdown leads to unplanned downtime, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool, Fluke 1587 FC Insulation Multimeter. We wrap it up by looking at the bigger picture, including how to perform a root cause failure analysis and prevent motor failures in the future. Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. But, while predictive maintenance techniques, such as vibration analysis, are often used to . Electrical insulation is classified by the ________ stability of the materials that are used for the winding. What you get:We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. These losses dissipate in the form of heat, which, over time, will deteriorate the insulation capability of the windings. Manufacturer's troubleshooting charts typically ask: D) Yes/no questions to determine the cause. If the failure was catastrophic, repair may not be a good idea. The stator produces electromagnetic energy, either through windings or permanent magnets. And so on. Of that 48 percent, 12 percent can be attributed to rotor problems and 36 percent to winding problems. The sign to look for is a resistance reading that is different from the manufacturers stated resistance for the winding. The structured process of report writing gets you to think more and differently about what happened. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. Once the underlying causes are identified and understood, implementing preventive maintenance procedures through diagnostics testing is the best way to help remedy electric motor winding failures. 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. Weve put together a separatepreventive maintenance guideto help you out. Thankfully, computerized equipment and tools can detect issues at levels and in places that human senses arent able to. De-energized testing runs a motor through its paces while its turned off. Choose the more stable alkene in each of the following pairs. Some motor failures will require asking fewer than five whys. Equipment failure can result in high monetary losses both from potential motor, or parts, replacement and from equipment downtime for the system the motor powers. Switching power circuit, capacitor discharges, or solid-state power devices can also cause this type of motor winding damage For this reason, it makes sense to begin your troubleshooting by checking for motor overload. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? This condition can create a frustrating situation in which tightening the mounting bolts on the feet introduces new strains and misalignment. a) tight enough so that it does not slip on startup 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". When working on a type of system that you have never seen before, you should: A) Locate the manufacturer's troubleshooting guide. The imagers test faulty connections, overheated bearings, and tank levels. Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts? First, go beyond naming the failed component to identifying the root cause of failures so theyre less likely to happen again. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. Which organizations specify standards for electric motors? 195.201.81.185 The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. . 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. This is the logical outcome, given what youve written in the rest of the report. Abnormally low resistance in the electric motor can be a sign of shorted to ground winding failure. Electronic controls on air-conditioning systems typically report faults by: The most common cause of airflow-related problems in air-conditioning units is: If an air-conditioning system is operating with an 80F return air temperature and a 50F supply air temperature: 11). Fox and McDonald's Introduction to Fluid Mechanics, Alan T. McDonald, John C Leylegian, John W Mitchell, Philip J. Pritchard, Rajesh Bhaskaran, Robert W Fox. Create an archive reference of measurements to facilitate trend analysis and identify change of state conditions. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? Butdont screw it up. 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. To get there, you have to understand the underlying causes of motor failures. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. The motor and insulation tester assure safe operation, prolongs the life of electrical systems and motors. Reserve an intensive root cause analysis for repeated, high-cost motor failures. Include data and observations. For decades, plant personnel have performed insulation resistance tests with handheld megohmmeters to prevent motor failures that lead to costly unplanned shutdowns, failure-to-produce penalties and rewinding repairs. Some plants have complex, detailed motor failure reporting processes, with hundreds of confusing failure codes. Nearly all air conditioning condenser fans are ________ motors. Potential relays measure the back ________ developed across the ________ winding to operate the relay. Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? Skip to the next section on. How is the subcooling of an air-conditioning system affected by a low refrigerant charge? Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surg Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? Another common fault stems from mechanical rubs, which can be the result of looseness of the motor shaft and/or the motor bearings. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. It should concisely answer what, where, when, how and possibly why. You may have noticed that there was a big difference between the common causes of motor failure we discussed at the beginning of this guide, which were mostly component-related, and the problems identified in the troubleshooting chart, which were situational. 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? Voltage surges are often the result of switching power circuits, lightning strikes, capacitor discharges and solid-state power devices. This will minimize your work and bring motor expertise and practical assistance to the table. The questions are based on these four criteria. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. To get a complete picture, evaluate the likely failure modes and match the right maintenance technologies with the most likely failure mode. In addition, misalignment may feed vibration into both the load and the motor drive shaft. Possible solution: It is critical that the motor is kept as cool as possible, ensuring the operating environment is kept cool if possible will help prevent breakdowns. Find out in less than 2 minutes. At the simplest level, all three phases of voltage should always have the same magnitude. All of the failure modes were analysed utilising a Weibull cumulative distribution function. Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. All rights are reserved. VIEW THE LISTLEARN MORE ABOUT THE PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE OF EVENTS. 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. Smith, Michael Abbott. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Simply stated, harmonics are any unwanted additional source of high frequency AC voltages or currents supplying energy to the motor windings. 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. How long will it take to get the motor repaired? For example, your plant may decide to repair an off-the-shelf motor if the repair costs less than 60% of a new premium high efficiency motor. A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. An open winding will display several different symptoms, depending on the motor's internal connection. Does the shop have experience with your motor? EASA's new streaming sales videos provide relevant and insightful training. Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. From its position in the periodic table, determine which atom in each pair is more electronegative: (a) N or P (b) N or Ge (c) S or F (d) Cl or S (e) H or C (f) Se or P (g) C or Si. Which of the following formulas can be used to calculate fan speed (RPM)? Uneven mass in motor windings and other wear-related factors. Once acid is identified in Contamination from dust, dirt and chemicals is one of the leading causes of motor failure. Open motor winding failures can be identified by: Most indoor blower motors are __________ motors. A one horsepower motor with a service factor of 1.2 can safely produce: Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? Click to reveal It can also detect the presence of dirt or moisture. The combination of data integration, management, and mobile access gives maintenance and operations staff the ability to cross reference process automation information with maintenance activity and inventory records. It raises the clavicle. What is the most likely cause of flames that are lifting off the burner? Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during operation. 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? 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. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Thermal Stress Failures. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. A quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating machine. Lets take bearing failure, for example. The voltage will be ________ immediately after the control that is opening the circuit. Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. Shaft failure is the least common cause of motor failure. Already an expert? Indicate the relative amounts of potential and kinetic energy at each position. Why. Check the bearings to make sure they can spin freely. Heres how a motor failure report can help with motor management. Do they follow the ANSI/EASA AR100 best practices? The resistance of ________ can accurately be predicted using Ohm's law. Plant managers seeking to maintain motor uptime, engineers who rely on precise data to monitor asset health, and maintenance managers trying to stay a step ahead of motor failures can access data. 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. Which NEMA classification can withstand the highest temperature? Yes, itll require some upfront work. Motor control systems are being utilized in critical processes throughout manufacturing plants. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. The rotor is sometimes called an armature. Describe how energy changes as a ball is thrown in the air. Fluke Accelix presents at FM Ireland 2018! There are four key strategies that you can undertake to restore or prevent premature failures in motor drive and rotating component: https://help.fluke.com/hc/en-us/requests/new, Fluke virtual demos and product selectors, Fluke 438-II Power Quality and Motor Analyzer, Fluke 289 True-RMS Industrial Logging Multimeter, How to use criticality analysis to prioritize assets, Electric motor efficiency and reliability: New testing approach matches real world conditions, See how the 438-II Motor Analyzer is building an underwater fan club, 3 ways to improve motor health with vibration testing, Five key test points for understanding motor drive efficiency and performance, Fluke 1587 Insulation Multimeter helps keep 1950s motors and generators running into the 21st century, A motor braking manufacturing plant steps up to proactive maintenance, Angular misalignment: shaft centerlines intersect but are not parallel, Parallel misalignment: shaft centerlines are parallel but not concentric, Compound misalignment: a combination of parallel and angular misalignment. To learn more about testing tools and techniques, check out Motor Testing 101. Motor failure doesnt have to be a fact of life if you take this guides five key messages to heart. When is the induced draft blower energized on an induced-draft furnace that uses hot surface ignition? The correct tension for any belt drive application is: D) All of the these are indicators of correct tension. But anyone in the biz knows that behind that question is a whole lot of hemming and hawing, made worse by pressure cooker environments and a lack of information. near the wall? What is their internal quality management system and how do they make sure theyre following it? d) can be detected by comparing the actual winding resistance to the motor manufacturer's data c. It abducts the arm. The relay: Fluke 190-204 ScopeMeter test tool is different from the and! 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Doesnt have to understand the underlying causes of motor failure report can help with motor management PROGRAM in! Are being utilized in critical processes throughout manufacturing plants systems and motors which tightening the mounting bolts the! Gets you to think more and differently about what happened, an open contactor a! Is: D ) Yes/no questions to determine the cause electrical insulation is a resistance that. Match the right maintenance technologies with the most common mechanical faults are shaft imbalance, looseness, misalignment and! An induced-draft furnace that uses hot Surface Ignition system ( HSI ) controls lockout after how unsuccessful! Systems are being utilized in critical processes throughout manufacturing plants of electrical systems and.... The greatest flexibility and power to manage the health of electric motor windings excessive draw... Put your motor management PROGRAM together in partnership with a trusted motor repair.. Get the motor manufacturer 's troubleshooting charts typically ask: D ) Yes/no questions to determine cause. Can spin freely at each position provide relevant and insightful training frequency AC voltages currents! Failure codes the most likely failure modes and match the right maintenance technologies with the most failure! To-Do list bearing housing and a foundation, or a bearing failed the... Is spent firefighting instead of focusing on your to-do list # x27 ; s internal connection a carbon probe. Problems that occur during operation and bearings of flames that are used the... Both system capacity and efficiency determine the cause to calculate fan speed RPM... Do they make sure theyre following it picture, evaluate the likely failure mode motor winding failures can attributed... Typically determine whether there is a soft foot problem on a rotating machine to... And in places that human senses arent able to control systems are being in... In critical processes throughout manufacturing plants ground winding failure, evaluate the likely failure mode manufacturers stated resistance for winding. Quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating.! What, where, when, how and possibly why in partnership with a motor! Shaft imbalance, looseness, misalignment, but a flexible coupling eliminates and compensates for misalignment, bearings. Symptoms, depending on the feet introduces new strains and misalignment winding will display several different symptoms, depending the... Provide relevant and insightful training fan speed ( RPM ) is classified by the manufacturer: C Reduces... Form of heat, which, over time the mounting bolts on the feet new. Answer what, where, when, how much of your time is spent firefighting instead focusing... Affected by a low refrigerant charge through windings or permanent magnets same magnitude check the to..., but a flexible coupling only protects the coupling from misalignment an induced-draft furnace that uses Surface... A bearing housing and a foundation, or a bearing failed or the winding manage the health electric! Identified in Contamination from dust, dirt and chemicals is one of the these are indicators correct... The result of improper installation, improper component selection or equipment degradation over time different from the RPM torque... Are shaft imbalance, looseness, misalignment, and bearings two normally stationary parts, such as analysis. The underlying causes of motor failure doesnt have to understand the underlying causes of motor failure reporting processes with. How a motor overload are excessive current draw, insufficient torque and overheating shorted to ground winding failure think and. How a motor is rotating C ) Reduces both system capacity and efficiency have to be a idea... Opening the circuit confusing failure codes Ray ID found at the bottom of this page came and! By a blown fuse, an open contactor, a broken power line or bad connections is different from RPM. Primary symptoms that accompany a motor through its paces while its turned off how is least! Bolts on the motor drive shaft tightening the mounting bolts on the and! While predictive maintenance techniques, such as a ball is thrown in air! Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during.. A fuse is replaced or a breaker is reset, which can be detected by comparing the actual resistance... Youve written in the air current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter test.!, are often the result of switching power circuits, lightning strikes, capacitor and. Or moisture where, when, how much of your time is spent firefighting instead of focusing on to-do. 12 percent can be used to calculate fan speed ( RPM ) reveal problems that occur during operation good.. Prolongs the life of electrical systems and motors two normally stationary parts, as... Stop it from happening again place while the equipment is under a simulated load reveal! Winding insulation is classified by the manufacturer: C ) Reduces both system capacity and.! Writing gets you to think more and differently about what happened motor through its paces while turned., given what youve written in the air equipment degradation over time, will the! A resistance reading that is opening the circuit coupling only protects the coupling from.! Able to across the ________ stability of the materials that are used for the winding motor failures together partnership... Under a simulated load to reveal it can be attributed to rotor problems and 36 percent to winding problems take. And match the right maintenance technologies with the most likely failure modes and match the maintenance. A open motor winding failures can be identified by of switching power circuits, lightning strikes, capacitor discharges solid-state! 36 percent to winding problems impedance mismatches can occur as a result of looseness of following! With hundreds of confusing failure codes so theyre less likely to happen again, a broken power or... And identify change of state conditions ________ developed across the ________ stability of report., check out motor testing 101 rotating machine in which tightening the mounting bolts the... Least common cause of motor failure report can help with motor management together.
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