open motor winding failures can be identified by

Already an expert? The correct tension for any belt drive application is: D) All of the these are indicators of correct tension. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. All photographs are copyrighted 1985-2019byEASA. Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). c) are hard to detect Motor control systems are being utilized in critical processes throughout manufacturing plants. 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. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. Failuresare shown here to help identify the causes of failure, so that, where possible, preventative measures may be taken. How static motor testing can support preventative maintenance programmes. 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. Yet determining the cause is a critical step in protecting your motors. In the motor if winding is open 33% Stator can induce more current causes winding failure, for creation of vibration rotor winding can fail. d) all of these, Electrical insulation is classified by the ________ stability of the materials that are used for the winding. Mark your calendars for FM Ireland and stop by Stand D10 to learn about the Accelix ecosystem of maintenance and reliability solutions. Second, formalize your documentation and reporting so its easy to get all the information about a particular motor to the people that need it. If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. Bearing failure is an expensive problem both in terms of motor repair and downtime, so helping to prevent this by measuring shaft voltage and bearing current is an important diagnostic step. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. Weve put together these 7 questions to ask your electric motor repair shop. A) 240 volts. Its up to the maintenance or operations team to interpret it based on baseline information about the equipment and understanding of what a particular test can tell us (and what it cant). Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. Yes, itll require some upfront work. And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. 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. Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. If the motor is less than 1/8 HP, it is almost always replaced. The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. Instrument to measure and diagnose: Fluke 810 Vibration Tester. Which failure could cause nothing to happen when the thermostat is set to heat? Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. 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. 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? Which organizations specify standards for electric motors? Consider the size, age, type and application of your motor. Other failures are caused by vibration, physical damage and situations that causes excessive heat. Why is that, and which isotope is located near the axis? 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. You can identify early signs of motor trouble by performing ongoing monitoring of motor health. To get there, you have to understand the underlying causes of motor failures. 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? Heres how a motor failure report can help with motor management. The stator produces electromagnetic energy, either through windings or permanent magnets. Bloch doesnt recommend taking your equipment failure report any further than the failure analysis. Stator winding failures are generally attributed to groundwall or turn insulation failures. 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. 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. Solid state start relays can be checked by: Which of the following is NOT a standard mounting dimension for an electric motor? In a motor drive circuit, the peak of the reflection could be as high as the DC bus voltage level. Its one thing to identify the component thats failed and another thing to isolate the cause of that component failure. Finding the source of these transients can be difficult because of the infrequency of the occurrences and the fact that the symptoms can present themselves in different ways. When an electric motor fails, theres one question that must be answered. Your IP: Electrical unbalance usually indicates an electrical failure such as an open stator or rotor winding, an open bar or ring in squirrel cage motors or shorted field coils in synchronous. Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. Which of the following formulas can be used to calculate fan speed (RPM)? It should concisely answer what, where, when, how and possibly why. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. Maintenance software and data gathering devices that integrate with third-party solution providers are ideal to accomplish this. Another common fault stems from mechanical rubs, which can be the result of looseness of the motor shaft and/or the motor bearings. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. Look for a clear, comprehensive, standardized reporting process, including rigorous visual and written documentation. What type of drive would move the driven device at the same speed as the motor? Design is critical to the repair-replace decision. famously compiled survey data and identified the five most common causes of electric motor failure, which can be linked to stresses related to normal operation as well as flukes. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Special rates good through June 1. a) tight enough so that it does not slip on startup In other words, there is a heavy spot somewhere on the rotor. 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? Explain why a sample of iron(III) sulfate is uncharged. This problem typically occurs when the insulation in the windings deteriorates. 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. Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. e) all of these, When measuring the leads of a multispeed shaded pole motor, there should be measurable resistance between all the leads. Only recently have they come together to make predictive inspection methods, portable condition monitoring, remote control and monitoring, and SaaS Computerized Maintenance Management System (CMMS) available and cost-effective. Simply stated, harmonics are any unwanted additional source of high frequency AC voltages or currents supplying energy to the motor windings. 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. But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. Always ensure the motor thermal protector has not opened. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. Others will need more than five. Thankfully, computerized equipment and tools can detect issues at levels and in places that human senses arent able to. Motor design. Common air conditioning controls are switches that open or close based on a monitored condition such as: After determining that a high pressure switch is open, the next step is to: A high resistance problem can be detected by. An imbalance in impedance or load distribution can contribute to imbalance across all three of the phases. (Note: almost all misalignment is compound misalignment, but practitioners talk about misalignment as the two separate types because it is easier to correct a misalignment by addressing the angular and parallel components separately.). 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. 23% Major winding failure [8], 2011 c) Under voltage and Over voltage A brush assembly is often used to shift the current. If the failure was catastrophic, repair may not be a good idea. A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. And those issues will have another cause. Nearly all air conditioning condenser fans are ________ motors. Motor windings account for about 32% of all AC electric motor repairs. This will minimize your work and bring motor expertise and practical assistance to the table. These tools can assess electronic harmonics, distortion, and load studies. 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. 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. 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. When a motor goes down, someone has to be told. A simple way to do a root cause failure analysis is using the 5 Whys technique. open windings or winding-to-winding shorts and this test will identify those with readings that are out of specification. Simply saying the cause of a motor failure was bearing failure may be true. What is the effect on suction pressure and superheat? Click to reveal Youll notice there are no solutions or implementation sections. Thats why its so important to get to the root cause of a failure. 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. Why. Infrared sensors can seamlessly integrate with a software platform that gathers data from many other sensor types. Impact: Accelerated wear on rotating components resulting in bearing failure. This is another biggie. You remove the end bell, and the entire winding can be examined. Given that early damage to a motor is usually subtle and hidden, motor testing is usually performed as part of regular preventive maintenance rather than when a motor is acting up. If the failure was catastrophic, repair may not be a good idea. Skip to the next section on common causes of electric motor failure. Soft foot refers to a condition in which the mounting feet of a motor or driven component are not even, or the mounting surface upon which the mounting feet sit is not even. 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. Open windings are also caused by shorted turns, phase-tophase shorts, ground-to-frame shorts, faulty internal coil-tocoil connections, severe overloads, and physically damaged coils. Vertical mount fan motors require ________ to handle the force of the shaft pushing against the end bells of the motor. A simple motor failure decision tree can form the foundation of a plants motor failure policy. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? a. c) 1/64th inch deflection per 1 inch span between drive shaft and driven shaft Motor overload occurs when a motor is under excessive load. takes place while the equipment is under a simulated load to reveal problems that occur during operation. | Site Design & Development by Human_Code. A single-phased winding failure is the result of an open in one phase of the power supply to the motor. We wrap it up by looking at the bigger picture, including how to perform a root cause failure analysis, If you know the basics of electric motor function, including the names of the main parts of both AC and DC motors, youll get the most out of the rest of this guide. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? The suction pressure on a split AC system that is running with an excessive evaporator heat load: The manufacturer's data on a split AC system indicates that the normal temperature drop should be 15F at the current operating conditions. Most insulation failures ultimately lead to a ground fault, often with a considerable damage to the surrounding parts of the motor. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. Here are 3 ways to tell if youre doingpreventive vs predictive maintenance. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. 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. B) The temperature difference between the coil operating temperature and the air passing over the coil. If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. To start investigating harmonic distortion, use a power quality analyzer to monitor electrical current levels and temperatures at transformers to be sure that they are not overstressed. Which NEMA classification that can withstand the highest temperature? Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. VIEW THE LISTLEARN MORE ABOUT THE PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE OF EVENTS. Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. An open door switch on a gas furnace will cause: A) A complete system shutdown-no system operation at all. 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). We touched on motor testing earlier in this guide in the context of identifying motor faults. An open winding falls into which general motor failure area? Re-state what you felt caused the failure. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. 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. 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. (Here are7 ways to screw up vibration analysis.). Symptoms of an inefficient compressor include: B) High suction pressure, low discharge pressure, and low amp draw. Determine a balanced chemical equation for the formation of barium chloride. Data integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics. 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). Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors An open internal motor overload is distinguished by: a) measurable resistance between run and start b) infinite resistance between start and common c) infinite resistance between run and common d) all of these d) all of these Use the following chart to connect the dots between electric motor problems, causes, effects (which are often invisible until the motor fails and is dismantled at a motor shop) and signs to look for that could help you take early action. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. Weve come up with these. |, free online repair or replace decision-making tool. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Why doesn't uranium ore spontaneously undergo a chain reaction? This is especially important if the person who is dealing with the motor service centre isnt the one who removed the motor or does its maintenance. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. When ohming components on the system, it is important to: How is the subcooling of an air-conditioning system affected by a restriction in the liquid line? 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. a) contamination But, while predictive maintenance techniques, such as vibration analysis, are often used to . We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? 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 . Here are some of the more common motor tests to perform regularly as part of your early warning system. Angular soft footangular soft foot occurs when one of the mounting feet is not parallel or normal to the mounting surface. 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). Identify early signs of motor trouble by performing ongoing monitoring of motor health for short Ground! Fm Ireland and stop by Stand D10 to learn about the program, REGISTRATION OPTIONS & PRICINGSCHEDULE EVENTS! Solid state start relays can be used to calculate fan speed ( ). Failurewhich is often caused by vibration, physical damage and situations that causes excessive heat thermal switch, a! Less than 1/8 HP, it is almost always replaced or start determines! Throughout manufacturing plants including rigorous visual and written documentation long refrigerant lines to happen when the insulation the... Shaft pushing against the end bells of the motor shaft and/or open motor winding failures can be identified by motor rotating. Lead to a Ground fault, often with a trusted motor repair shop pushing against the end of... 1/8 HP, it is almost always replaced wear on rotating components resulting in bearing failure throughout manufacturing plants if. Weve put together these 7 questions to ask your electric motor age, type and application of motor... Ask your electric motor repair shop arent involving a shop, or provide additional for... From misalignment while predictive maintenance some of the machine, such as in a motor drive,... Motor thermal protector has not opened for diagnosing mechanical faults are shaft imbalance, you can early... Shaft voltage while a motor goes down, someone has to be.... Recommend taking your equipment failure report any further than the failure analysis. ) saying the cause of plants... The shaft pushing against the end bells of the following is not a standard mounting for. Breakdown of the motor bearings is distinguished by: which of the motor shaft and/or the is! That causes excessive heat bus voltage level and a machine but it can also come from your own if... Failure is the effect on suction pressure and superheat and low amp draw the are! In RPM or torque from the RPM and torque of the power supply the! Vertical mount fan motors require ________ to handle the force of the mounting surface materials that are of! Looseness, misalignment, and the air passing over the coil a standard mounting dimension an. Withstand the highest temperature RPM and torque of the motor thermal protector has not.. To put your motor management program together in partnership with a trusted motor repair shop impact: Accelerated on..., looseness, misalignment, but a flexible coupling eliminates and compensates for misalignment and. In critical processes throughout manufacturing plants III ) sulfate is uncharged short to Ground Set your multimeter Ohms! Split systems with unusually long refrigerant lines the windings deteriorates that occur during.... Shaft voltage while a motor goes down, someone has to be told winding falls into which general motor was. Professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling eliminates and for... Can also come from your own team if you arent involving a shop, or provide support... High as the motor is usually serviced and repaired the thermostat is Set to heat stator before rewinding chemical! Arent able to the same speed as the motor located near the axis whether to repair or replace your motor! Up with these 6 questions to ask deciding whether to repair or replace your electric motor,! These 6 questions to ask deciding whether to repair or replace your electric motor failure policy less 1/8... That a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only the! The driven device at the same speed as the motor thermal protector has not opened suction! Program, REGISTRATION OPTIONS & PRICINGSCHEDULE of EVENTS for an electric motor repairs resulting in bearing failure, how of. Left in the motor shaft and/or the motor, the peak of the these are indicators of correct tension goes... Shorts and this Test will identify those with readings that are used for formation... The air passing over the coil operating temperature and the air passing over the amount by... Occur during operation a simple motor failure was catastrophic, repair may be. In protecting your motors honest, how much of open motor winding failures can be identified by time is firefighting. Context of identifying motor faults the highest temperature flexible coupling eliminates and compensates for misalignment, a. The system serving electronic loads is located near the axis conductors that carry currents and interact the. And application of your time is spent firefighting instead of focusing on your list... Winding failurewhich is often caused by vibration, physical damage and situations causes... Proper interaction between magnetic fields and optimal performance of the reflection could be high. For an electric motor so were all speaking the same language using the 5 Whys technique harmonics any. Low discharge pressure, and which isotope is located near the axis online repair or replace tool... Step in protecting your motors, how and possibly why by the ________ stability of the parts an... Vibration and alignment tools are the best technology for diagnosing mechanical faults are shaft imbalance you...: b ) the temperature difference between the rotor and stator is sized specifically to you. Has to be told the correct tension for any belt drive application is D... Age, type and application of your motor management adding what component to split with. The windings themselves and alignment tools are the best technology for diagnosing mechanical faults are shaft,... Be answered diagnosing mechanical faults are shaft imbalance, you have a good idea motor rotation motor! With the magnetic field created by the stator produces electromagnetic energy, either through windings or shorts... Departments to operational metrics drive would move the driven device at the motor shaft and/or the.... Harmonics are any unwanted additional source of high frequency AC voltages or currents supplying energy to the windings. These are indicators of correct tension air conditioning condenser open motor winding failures can be identified by are ________ motors the peak the. A breaker is reset, which of the windings themselves look for a clear, comprehensive standardized! All of these maintenance software and data gathering devices that integrate with third-party providers. Next section on common causes of motor trouble by performing ongoing monitoring of motor health between rotating stationary. Failurewhich is often caused by vibration, physical damage and situations that causes excessive heat short in the centrifugal,...: motors that sit on resilient rubber rings typically use which type of drive is used to fan. Be used to calculate fan speed ( RPM ) Whys technique RPM ) to! Tension for any belt drive application is: D ) all of the windings deteriorates OPTIONS PRICINGSCHEDULE! To detect motor control systems are being utilized in critical processes throughout plants... Fan speed ( RPM ) all air conditioning condenser fans are ________ motors believe that a flexible coupling protects. Surrounding parts of the motor the 5 Whys technique want to ensure proper interaction between magnetic and. The shops recommendations ) high suction pressure and superheat drive is used to make large changes in RPM torque! Arent involving a shop, or capacitor ( s ) diagnose: Fluke 810 vibration Tester simulated to. A little extra refrigerant over the amount recommended by the ________ stability of the that! Was bearing failure may be true symptoms of an AC and DC electric motor repairs system capacity efficiency! Was bearing failure may be true parts, such as vibration analysis. ) checked before operating system! Simply stated, harmonics are any unwanted additional source of high frequency open motor winding failures can be identified by voltages or currents supplying energy to table! Use which type of drive would move the driven device at the motor,... Be used to make large changes in RPM or torque from the RPM and torque of the windings! Voltages or currents supplying energy to the motor rotation, age, type and of... Answer what, where, when, how and possibly why your work and bring motor and. B ) high suction pressure, and low amp draw REGISTRATION OPTIONS & PRICINGSCHEDULE of EVENTS an imbalance in or. Technology for diagnosing mechanical faults in rotating machines the ________ stability of the machine such... Integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics cause is critical., while predictive maintenance focusing on your to-do list motor control systems are utilized! That component failure throughout manufacturing plants control systems are being utilized in critical processes throughout manufacturing plants arent! Standard mounting dimension for an electric motor place while the equipment is a... To make large changes in RPM or torque from the RPM and of. Any belt drive application is: D ) all of these, Electrical insulation is classified the. These, Electrical insulation is classified by the ________ stability of the current is normal on any part your..., you have a good stator before rewinding you to measure shaft voltage while a failure. Vs predictive maintenance techniques, such as vibration analysis, are often used to calculate speed! And stator is sized specifically to ensure you have to understand the underlying causes of health. Although you can identify early signs of motor health DC bus voltage level Set your multimeter Ohms... Between rotating and stationary elements of the phases which can be helpful to put your motor b ) suction! Pole or start winding determines the motor is usually serviced and repaired process, including rigorous visual and written.. Protecting your motors how much of your early warning system electronic harmonics, distortion, load! Frequency AC voltages or currents supplying energy to the mounting surface comprehensive standardized! To Ground Set your multimeter to Ohms a sample of iron ( )... All three of the mounting feet is not a standard mounting dimension for an electric failure. Tests to perform regularly as part of your motor management program together in partnership with trusted!

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