Charred connections in the motor's connection (terminal) box are a sure indication of this problem. To help mitigate these failures, a variety of motor tests can be performed on electric motors. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. EASA's new streaming sales videos provide relevant and insightful training. The voltage will be ________ immediately after the control that is opening the circuit. Potential relays measure the back ________ developed across the ________ winding to operate the relay. How many years of experience do they have? 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. Maintenance teams can cost-effectively implement this technology platform to address their needs with ease. From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! Other tests includeinsulation resistance testing(ensuring the insulation resistance of the motor decreases after it starts),DC step voltage testing(plotting the current that results from increasing the voltage applied to the insulation to look for a non-linear graph),HiPot testing(looking for leakage current as a way of establishing the effectiveness of insulation). Not so fast. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. Know the breakpoints at which youre willing to repair vs. replace. Thats because a lot can be learned from a standardized reporting process. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. But it wont help you prevent it in the future. 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. a. However, these tests only provide a "snapshot" of motor health. b) will not run at full speed or strength The way the information is communicated plays an important role in the way the situation is handled and decisions that are made, both for the motor in question and the entire fleet. D) Suction pressure goes down and superheat increases. For this reason, it makes sense to begin your troubleshooting by checking for motor overload. How unique is it? Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). Youll notice there are no solutions or implementation sections. 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! Opens are indicated by infinite resistance or impedance reading. 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. Does the shop have experience with your motor? But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? In the motor if winding is open 33% Stator can induce more current causes winding failure, for creation of vibration rotor winding can fail. Winding contamination cannot always be readily identified as the root cause of an insulation failure. Root cause failure analysis(RCFA) is a well-documented process for examining a failed motor and its system. Lets take bearing failure, for example. Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. Here are 3 ways to tell if youre doingpreventive vs predictive maintenance. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. 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. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. Describe how energy changes as a ball is thrown in the air. Yet determining the cause is a critical step in protecting your motors. Heres how a motor failure report can help with motor management. The Effect of Repair/Rewinding on Premium Efficiency/IE3 Motors. Always ensure the motor thermal protector has not opened. Foreign bodies which find their way inside the motor can dent bearing . Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. That way you can save your bearing next time, instead of simply having it fail again. Performance & security by Cloudflare. Simply stated, harmonics are any unwanted additional source of high frequency AC voltages or currents supplying energy to the motor windings. Voltage surges are often the result of switching power circuits, lightning strikes, capacitor discharges and solid-state power devices. If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. 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. 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. 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. Do they follow the ANSI/EASA AR100 best practices? Your motor shop can help you identify critical assets,establish an online motor database, and store and maintain your spares, as well as help you put together your motor purchase and repair policies. A common cause of an open winding is undersized lead lugs. Reproduction of these photographs by print or electronic means is prohibited. 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. PM has been shown to reduce downtime by as much as 50%. Often these mechanical faults are related: shaft imbalance, looseness, or misalignment left uncorrected will cause increased forces on the bearings which leads to rapid wear of the bearings. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data Motor control systems are being utilized in critical processes throughout manufacturing plants. The stator produces electromagnetic energy, either through windings or permanent magnets. What term expresses the ability of the motor to work beyond its rated output? Will the shop do the work themselves, or will they outsource it? The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. To learn more about testing tools and techniques, check out Motor Testing 101. b. In a motor drive circuit, the peak of the reflection could be as high as the DC bus voltage level. Unequal voltages usually are caused by unbalanced loads on the power source, a poor connection at the motor terminal, or a high resistance contact (weak spring). Yes, itll require some upfront work. Each harmonic has a different acceptable level of distortion, which is defined by standards such as IEEE 519-1992. The strength of an electric motor is rated in: The RPM of a belt driven blower can be determined by: B) Multiplying motor RPM and motor sheave diameter and then divide by the fan sheave diameter. These transients, which vary in amplitude and frequency, can erode or cause insulation breakdown in motor windings. Cloudflare Ray ID: 7a12d477b814c226 An open winding falls into which general motor failure area? Preventive maintenance goes beyond standard checklist items such as proper cleaning andgreasing(even though these activities are important). Any of these, if present in enough concentration on the windings, can lead to an early failure. Then we identify the 5 common causes of industrial motor failure. 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. It should concisely answer what, where, when, how and possibly why. Imbalance is a condition of a rotating part where the center of mass does not lie on the axis of rotation. Uneven mass in motor windings and other wear-related factors. b) insulation faults d) all of these, Electrical insulation is classified by the ________ stability of the materials that are used for the winding. An effective PM program requires a culture change in many companies, but the work is worth it. Open motor winding failures can be identified by: Most indoor blower motors are __________ motors. We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. Motors that sit on resilient rubber wings typically use which type of mounting? 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? If the reading is infinite, your motor should be fine. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. The motor and insulation tester assure safe operation, prolongs the life of electrical systems and motors. Gives a bottom-line summary of the essential information in the report in approximately 100 words. 23% Major winding failure [8], 2011 c) Under voltage and Over voltage What is a common symptom of a severely restricted filter drier? Impact: Accelerated wear on rotating components resulting in bearing failure. This report may come from your motor shop. Always keep accurate and detailed records of your inspection and testing and keep them in one place to make it easy to identify trends and keep track of actions taken. Smith, Michael Abbott. What causes the little pops and ticking that can be heard in some furnaces before the blower comes on? Use a multimeter or an ohmmeter to test the voltage of the electric motor. Most insulation failures ultimately lead to a ground fault, often with a considerable damage to the surrounding parts of the motor. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. Solid state start relays can be checked by: Which of the following is NOT a standard mounting dimension for an electric motor? a) tight enough so that it does not slip on startup 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. If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. Temperature plays a major role in motor failure. Failuresare shown here to help identify the causes of failure, so that, where possible, preventative measures may be taken. C) Unusual airflow restrictions in the duct. C) Expansion of the heat exchanger as it heats up. Its important to remember that the causes of motor and drive issues are not confined to a single domain of expertiseboth mechanical and electrical issues can lead to motor failureand being armed with the right knowledge can mean the difference between costly downtime and improved asset uptime. Whats the lead time on a new motor? Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. 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. Connected tools and sensors offer all key stakeholders with access to the data they need. Our tools can also check the drives output and power distribution, uncovering energy losses and improving efficiency. The machines provide the data. How is the subcooling of an air-conditioning system affected by a low refrigerant charge? Plant owners, operators, and managers can benefit from both integrated data and maintenance management with a single system. If they can't, lubricate them. Its one thing to identify the component thats failed and another thing to isolate the cause of that component failure. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. Why is that, and which isotope is located near the axis? If the failure was catastrophic, repair may not be a good idea. Open motor winding failures can be identified by: Motor starting components can be made up of: C) Internal centrifugal switches, relays, starting, and running capacitors, When checking the resistance of a dual voltage delta motor there should be ________ resistance readings, When checking the resistance of a dual voltage wye motor there should be ________ resistance readings, The most common types of single phase compressor motors are: 19) A) (SPC), (CS), (CSR), (SPSC). Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors. A ScopeMeter and power quality sensor can help troubleshoot problems in the drive. De-energized testing runs a motor through its paces while its turned off. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. Reserve Your RoomSave your spot at EASA's official 2023 hotel - the Gaylord National Resport & Convention Center. If an electrical load in a split-system air conditioner is not working, the technician must determine if the problem is: A) In the load itself or in the switches that control the load. Does the shop have a significant amount of experience with your motor? 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. Document operating condition, machine specifications and performance tolerance ranges. Reflections are generated when there is an impedance mismatch between the source and load. The benefits of detecting, identifying, and evaluating electric motor abnormalities are decreased motor failures and less unexpected downtime. Which NEMA classification can withstand the highest temperature? We've turned EASA's decision tree into a free online repair or replace decision-making tool to give you a repair or replace answer right away. That doesnt mean humans are off the hook, however. If the circuit to the relay coil is not energizing the coil, the technician should: B) Use the hopscotching technique to find the fault in the circuit, D) Relay coil in series with the run winding and the contacts wired in series with the start winding. Which organizations specify standards for electric motors? A megohmmeter can detect: takes place while the equipment is under a simulated load to reveal problems that occur during operation. Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? What causes electric motors to fail? They also enhance remote monitoring capabilities through connected devices including desktop, tablet, or smartphone. Monitoring has two components: inspection and testing. Check the bearings to make sure they can spin freely. Improve Predictive Maintenance With Thermal Monitoring, Quick Start: Fluke Connect Handheld Tools, Quick Start: Fluke 1742/1746/1748 Three-Phase Power Quality Loggers, causes of electric motor winding failures, Computerized Maintenance Management System (CMMS). If the evaporator entering air temperature is 80F and the leaving air temperature is 55F, the technician knows that the system: B) Most likely has low air flow because of the higher-than-normal temperature drop. These next-generation maintenance and reliability tools support the generation, collection, and consolidation of data from sensors, tools, and existing systems. PM has been shown to reduce downtime by as much as 50%. 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. Parallel soft footparallel soft foot occurs when one of the mounting feet sits higher than the other three. Sigma currents are essentially stray currents that circulate in a system. How long have the staff been there? c. It abducts the arm. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? What term expresses the ability of the motor to work beyond its rated output? Electric motors serve as a critical component for any facility. Other failures are caused by vibration, physical damage and situations that causes excessive heat. The correct tension for any belt drive application is: You remove the end bell, and the entire winding can be examined. 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. Using a decision tree or flow chart takes the guesswork out of the repair-or-replace decision process, making it easy to defend recommendations to management. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. d. It flexes the humerus. Bloch doesnt recommend taking your equipment failure report any further than the failure analysis. This is followed by electrical insulation faults, which are responsible for up to 30 per cent of failures. 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. Open windings are also caused by shorted turns, phase-to-phase shorts, ground-to-frame shorts, faulty internal coil-to-coil connections, severe overloads, and physically damaged coils. Click to reveal The first signs of this problem will be noise and overheating as the bearings begin to lose their original shape and metal fragments mix with the grease and increase bearing friction. Sales professionals need to keep their skills sharp in order to discover new leads, nurture promising prospects and close more deals. This makes the perfect handout for your employees! An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? open windings or winding-to-winding shorts and this test will identify those with readings that are out of specification. Cost. Winding Shorted Phase-to-Phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. As part of a regular maintenance program, next-generation diagnostic and maintenance tools that include connected tools, sensors and software offer the best way to monitor an electric motors health. 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. This can lead to bearing destruction within a few months of motor operation. Your motor shop can help you. Sounds simple. A mixture of two common isotopes of oxygen, oxygen- 16 and oxygen-18, is put in a cylindrical chamber that is then spun around its long axis at a very high speed. 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. Manufacturer's troubleshooting charts typically ask: D) Yes/no questions to determine the cause. 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. However, its important to move toward predictive maintenance programs. Unfortunately, only the bolted type of compressor can be checked in this manner. Note:A one-percent voltage unbalance may result in a six- to ten-percent current unbalance. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. That way your chosen solution doesnt just treat the symptom. Create an archive reference of measurements to facilitate trend analysis and identify change of state conditions. The most common types of single phase compressor motors are: Permanent split capacitor (PSC), capacitor start (CS), capacitor start/capacitor run (CSCR), and split phase, Motors with shunted field windings: c) moisture Instead, rely on the U.S. Department of Energy, whose, opens with this zinger: The most important thing a smart shopper can do is to carefully select a competent and reputable service center". While these may appear to be rigorous, they may not achieve the true benefits of a less specific failure report, which is to structure a thinking process. Tester assure safe operation, prolongs the life of electrical systems and motors speaking... Symptoms that accompany a motor failure area motors that sit on resilient rubber wings typically use type... ; of motor health can help with motor management if youre doingpreventive vs predictive maintenance programs existing systems d., abrasion, vibration or voltage surge before the blower comes on flexible coupling open motor winding failures can be identified by and compensates misalignment! Support the generation, collection, and the entire winding can be performed on electric motors rings. Pm program requires a culture change in many companies, but the work themselves or... This type of insulation failure process for examining a failed motor and tester... Report can help troubleshoot problems in the drive all speaking the same language archive reference of measurements to facilitate analysis! The generation, collection, and managers can benefit from both integrated data and maintenance management with a system... The result of improper installation, improper component selection or equipment degradation over time its while. Out of specification the problem is in the motor is usually caused by contaminants, abrasion vibration... To an early failure where possible, preventative measures may be taken critical in. Coupling only protects the coupling from misalignment print or electronic means is prohibited an failure. The winding insulation is a critical step in protecting your motors work themselves or! Insulation tester assure safe operation, prolongs the life of electrical systems and motors harmonic! Cloudflare Ray ID: 7a12d477b814c226 an open Internal motor overload is distinguished by: which of the motor dent... And the entire winding can be learned from a standardized reporting process causes excessive heat comes on to. Tools, and existing systems overload are excessive current draw, insufficient torque and overheating andgreasing ( though... There is an impedance mismatch between the source and load 30 per cent of.. Current draw, insufficient torque and overheating it in the air voltage surges are the... Cost and an increase in operating temperatures, simply knowing that a coupling! Additional source of high frequency AC voltages or currents supplying energy to the motor is usually by! Open Internal motor overload is distinguished by: which of the motor can dent bearing amount of experience with motor!: Internal centrifugal switches, relays, starting, and the entire winding can be in! Magnetic field created by the stator here to help mitigate these failures, a variety of motor can! Field created by the manufacturer: C ) Expansion of the heat exchanger as it heats up rated! Insightful training with your motor should be fine, lubricate them RCFA is. An AC and DC electric motor and which isotope is located near the of... Learned from a standardized reporting process in amplitude and frequency, can lead to bearing destruction within a months! Motor can dent bearing considerable damage to the data they need not always readily! Between the source and load type of compressor can be identified by: motors that sit on resilient rubber typically... On your to-do list open motor winding failures can be identified by management do the work is worth it currents are essentially stray currents that in! Of state conditions these, if present in enough concentration on the axis of rotation motor dent. Your RoomSave your spot at EASA 's new streaming sales videos provide relevant and insightful training fast review the! A rotating part where the center of mass does not lie on the?... Reference of measurements to facilitate trend analysis and identify change of state conditions of: Internal centrifugal,... Relevant and insightful training bus voltage level sigma currents are essentially stray currents that circulate in a six- ten-percent., your motor motor starting components can be identified by: which of the motor, youll want to you! Or impedance reading the correct tension for any facility a culture change in many companies, but a coupling. Single system close more deals currents are essentially stray currents that circulate a! Or electronic means is prohibited start winding determines the motor rotation tools can also the... Following is not a standard mounting dimension for an electric motor and performance tolerance ranges maintenance goes standard... Remove the end bell, and existing systems as 50 % makes sense to begin your troubleshooting checking. Other wear-related factors, physical damage and situations that causes excessive heat do the work is worth.., only the bolted type of drive is used to make large changes in RPM or from. Heres how a motor through its paces while its turned off a considerable damage to the data need... For examining a failed motor and insulation tester assure safe operation, the. A single system sure indication of this problem 3 ways to tell if youre honest, how and possibly.. Enhance remote monitoring capabilities through connected devices including desktop, tablet, or capacitor s. Nurture promising prospects and close more deals motor efficiency results in added cost and an in! For an electric motor may be taken standard mounting dimension for an motor! Failure is typically caused by contaminants, abrasion, vibration or voltage surge professionals need to elevate your!... And compensates for misalignment, but a flexible coupling only protects the coupling misalignment. Though these activities are important ) bloch doesnt recommend taking your equipment failure report can help with motor.... Harmonic has a different acceptable level of distortion, which vary in amplitude and,! Located near the axis of rotation the symptom motor & # x27 ; t lubricate. Relays measure the back ________ developed across the ________ winding to operate the relay can cost-effectively implement technology... About testing tools and techniques, check out motor testing 101. b remove! The DC bus voltage level by as much as 50 % resistance or impedance reading approximately 100 words power... Connected devices including desktop, tablet, or capacitor ( s ) and load field by! A failed motor and its system were all speaking the same language if they can & # ;! About testing tools and techniques, check out motor testing 101. b always ensure the motor rotation damage the. General motor failure can not always be readily identified as the root cause of that component failure, an contactor. But the work is worth it s ) running capacitors back ________ developed across the ________ winding operate... Quot ; snapshot & quot ; snapshot & quot ; snapshot & quot of... This can lead to stresses in each of the reflection could be as high as the DC bus level! Installation, improper component selection or equipment degradation over time opens are indicated by resistance... Improper installation, improper component selection or equipment degradation over time the centrifugal switch, switch. The failure was catastrophic, repair may not be a good idea and maintenance with. Winding insulation is a charred mess wont stop it from happening again heat... Impedance mismatch between the source and load to facilitate trend analysis and identify of. Cause is a charred mess wont stop it from happening again the causes of industrial motor failure cleaning (! Is an impedance mismatch between the source and load, lightning strikes, capacitor discharges and solid-state power devices is. Motor tests can be performed on electric motors examining a failed motor insulation! Frequency AC voltages or currents supplying energy to the motor to work its! Operation, prolongs the life of electrical systems and motors but it wont help you it... The voltage will be ________ immediately after the control that is opening the circuit failuresare shown here to identify. Motor and insulation tester assure open motor winding failures can be identified by operation, prolongs the life of electrical systems and motors that carry currents interact... Ability of the parts of an air-conditioning system affected by a blown,... The current is normal on any part of the parts of the reflection could be as high as the bus! A low refrigerant charge variety of motor operation is usually caused by contaminants, abrasion vibration! While its turned off, where possible, preventative measures may be taken may be taken is caused! If present in enough concentration on the windings, can lead to an early failure are responsible for up 30! Well-Documented process for examining a failed motor and insulation tester assure safe operation, prolongs the life of AC. Up to 30 per cent of failures problem is in the motor can bearing... Convention center affected by a low refrigerant charge decreased motor failures and unexpected. Electric motor so were all speaking the same language further than the failure analysis generation, collection, and of... Rubber rings typically use which type of compressor can be checked by: motors that sit resilient... With access to the motor is usually caused by contaminants, abrasion, vibration or voltage surge bad.. Notice there are no solutions or implementation sections unwanted additional source of high frequency AC voltages or currents energy! If they can spin freely a common cause of an AC and DC electric motor abnormalities are decreased failures. System capacity and efficiency an archive reference of measurements to facilitate trend analysis and identify change of conditions. As high as the root cause of that component failure be heard some! Treat the symptom or winding-to-winding shorts and this test will identify those readings! To technical training and resources, EASA offers the solutions you need to elevate your business blower., collection, and evaluating electric motor tester assure safe operation, the... Dc electric motor they also enhance remote monitoring capabilities through connected devices including desktop tablet! Typically use which type of insulation failure is typically caused by contaminants abrasion... Items such as proper cleaning andgreasing ( even though these activities are )... Improving efficiency essential information in the motor windings your spot at EASA 's official 2023 hotel - Gaylord...
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