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. 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. VIEW THE LISTLEARN MORE ABOUT THE PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE OF EVENTS. Preventive maintenance goes beyond standard checklist items such as proper cleaning andgreasing(even though these activities are important). Maintenance software and data gathering devices that integrate with third-party solution providers are ideal to accomplish this. Heinz Bloch, an international expert who has written 23 books on machinery maintenance and reliability, says that a failure report doesnt need to be rigidly formatted to help you understand what really happened. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. 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. Open motor winding failures can be identified by: Most indoor blower motors are __________ motors. It should concisely answer what, where, when, how and possibly why. 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. Root cause failure analysis(RCFA) is a well-documented process for examining a failed motor and its system. 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. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. This is another biggie. Things to look for during an inspection of your motor include: Signs of corrosion, dirt or debris on components, including fins, windings, contacts and relay, A burning smell that may indicate overheating, Signs of wear on the commutator and brush assembly, Anything unusual with the motor mount, stator, rotor and belts, Dirt buildup, inadequate lubrication and signs of wear on bearings, A bearing housing thats hot to the touch, Loose connections, including in the starter switch and fuses\. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during operation. 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? An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Check each wire, including T1, T2, T3 and the ground wire. 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. Abnormally low resistance in the electric motor can be a sign of shorted to ground winding failure. Are you interested in learning more about how to determine the true cause of an electric motor failure? Timing. What is the most likely cause of flames that are lifting off the burner? Adjacent loads turning on or off, power factor correction capacitor banks or even distant weather can generate transient voltages on distribution systems. The resistance of ________ can accurately be predicted using Ohm's law. These transients, which vary in amplitude and frequency, can erode or cause insulation breakdown in motor windings. 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). A single-phased winding failure is the result of an open in one phase of the power supply to the motor. 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. Impact: Accelerated wear on rotating components resulting in bearing failure. 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. Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. 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. Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. 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. Winding shorted turn-to-turn Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. D) The large temperature drop indicates the airflow is less than required. A one horsepower motor with a service factor of 1.2 can safely produce: On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. Your motor shop can help you. However, electric motors can be prone to any number of issues that lead to motor faults and failures. The winding failures illustrated here are typical of what can happen is such circumstances. 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. These circulating currents can find their way through protective earth systems causing nuisance tripping or in some cases excess heat in windings. If the failure was catastrophic, repair may not be a good idea. Which NEMA classification can withstand the highest temperature? A) motors, When hopscotch troubleshooting, follow the schematic and move the meter lead on the control side of the circuit from one control to the next, checking the voltage in and out of the control. Are the techs CSA-certified? Insulation failures like this usually are caused by voltage surges. 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. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. Which of the following formulas can be used to calculate fan speed (RPM)? It adducts the humerus. Contamination from dust, dirt and chemicals is one of the leading causes of motor failure. Capture and document critical measurements at installation, before and after maintenance and on a routine basis. But wouldnt it be better to avoid failure in the first place? A newly installed valve or another component, An object striking, bending, or simply pressing on a pipe, Broken or lack-of pipe hangers or wall-mounting hardware. How long have the staff been there? Document operating condition, machine specifications and performance tolerance ranges. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. Motors are rated in either ________ or ________ operation. 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). 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. 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. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. A simple way to do a root cause failure analysis is using the 5 Whys technique. 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. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. Stator winding failures are generally attributed to groundwall or turn insulation failures. Motor control systems are being utilized in critical processes throughout manufacturing plants. This will help you identify patterns with a particular asset and make warranties easy to manage. Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. 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. There could also be thermal deterioration in all phases of the stator winding typically due to load demands exceeding the rating of the motor or by very high currents in the stator winding due to a locked rotor. When charging a capillary tube system that holds 100 oz., the charge must be: B) Within 5 percent, between 95 and 105 oz. Sales professionals need to keep their skills sharp in order to discover new leads, nurture promising prospects and close more deals. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. Instead of answering a bunch of questions from the motor shopwhich may require digging up information or recalling events from days or weeks agoyou hand the guys a report. These tools can assess electronic harmonics, distortion, and load studies. Should we repair the motor or replace it? 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. Check the bearings to make sure they can spin freely. However, if the motor is more than 10 years old and less than 1 HP, the motor is usually replaced. Note:Under-voltage and over-voltage (exceedingNEMAstandards) will result in the same type of insulation deterioration. 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. 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. A large inventory, including materials used for rewinding in both imperial and metric sizes, will reduce repair time. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. In DC motors, the commutator is a switch that reverses the direction of the electrical current to keep the rotor spinning. Always ensure the motor thermal protector has not opened. The questions are based on these four criteria. Mark your calendars for FM Ireland and stop by Stand D10 to learn about the Accelix ecosystem of maintenance and reliability solutions. 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 Severe thermal deterioration of the insulation in all phases of the motor normally is caused by very high currents in the stator winding due to a locked rotor condition. 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. Lets take bearing failure, for example. Skip to the next section on common causes of electric motor failure. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. However, these tests only provide a "snapshot" of motor health. You can email the site owner to let them know you were blocked. How many years of experience do they have? This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. b. a) will draw higher than normal amps The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. 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 offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. How static motor testing can support preventative maintenance programmes. This is another biggie. The purpose of this section is to give information to those who might not be familiar with your particular equipment or processes, including management and the motor shop. There are two kinds of soft foot: In both cases, soft foot can be caused either by an irregularity in the machine mounting feet, or in the mounting foundation upon which the feet rest. And those issues will have another cause. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. But, while predictive maintenance techniques, such as vibration analysis, are often used to . All rights are reserved. Is it well suited for the application, or is it time to spec a new motor that can better accomplish what your process demands? All of the failure modes were analysed utilising a Weibull cumulative distribution function. This makes the perfect handout for your employees! When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. The machines provide the data. Weve spent most of this guide talking about what to do when a motor fails. 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). Which NEMA classification that can withstand the highest temperature? 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. Start by completely disconnecting the spindle motor from all power sources. Some motor failures will require asking fewer than five whys. runs a motor through its paces while its turned off. How unique is it? Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors. 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. Does the shop have a significant amount of experience with your 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. To get there, you have to understand the underlying causes of motor failures. Thankfully, computerized equipment and tools can detect issues at levels and in places that human senses arent able to. The sigma currents are created as a result of the signal frequency, voltage level, capacitance and inductance in conductors. Which failure could cause nothing to happen when the thermostat is set to heat? The rotor is sometimes called an armature. 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? Heres how to set your motors up for success, not failure. Chances are, you arent the final decision maker on larger operational and capital expenditures. It treats the underlying condition that created the situation in the first place. Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. b) will not run at full speed or strength 4. The questions are based on these four criteria. The best way to diagnose an ECM motor is to: Turn off power to the unit, remove the control harness, and connect a test controller. We get it. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. An open winding falls into which general motor failure area? 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". A common cause of an open winding is undersized lead lugs. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. These next-generation maintenance and reliability tools support the generation, collection, and consolidation of data from sensors, tools, and existing systems. Sounds simple. The essential guide to troubleshooting, repairing and preventing industrial motor problems. 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). 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. Monitoring has two components: inspection and testing. But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? Iron(III) sulfate $\left[\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}\right]$ is composed of $\mathrm{Fe}^{3+}$ and $\mathrm{SO}_{4}^{2-}$ ions. A) Fan RPM = Motor RPM Motor Sheave Diameter Fan Sheave Diameter. C) Expansion of the heat exchanger as it heats up. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Already an expert? Do you need OEM parts or can your motor shop fabricate or source OEM-enhanced parts? The ________ is used to identify all the controls in series with the load. Symptoms of an inefficient compressor include: B) High suction pressure, low discharge pressure, and low amp draw. 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. What type of drive would move the driven device at the same speed as the motor? In the motor if winding is open 33% Stator can induce more current causes winding failure, for creation of vibration rotor winding can fail. Motor windings account for about 32% of all AC electric motor repairs. In addition, misalignment may feed vibration into both the load and the motor drive shaft. In a motor drive circuit, the peak of the reflection could be as high as the DC bus voltage level. Third, make your motor repair and replace decisions using an industry-accepted decision tree oronline decision toolto standardize and speed up your process. This is the first installment of a five-part series on common motor failures that will go on to cover motor windings, rotor bars, external conditions, and shaft couplings. To get a complete picture, evaluate the likely failure modes and match the right maintenance technologies with the most likely failure mode. 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: Why is that, and which isotope is located near the axis? Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. Create an archive reference of measurements to facilitate trend analysis and identify change of state conditions. Maintenance teams can cost-effectively implement this technology platform to address their needs with ease. Find out in less than 2 minutes. Investigating the cause of a failure in an open-type motor is comparatively simple. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Because 30% of motor failures are caused by overloading, it is important to understand how to measure for and identify motor overloading. Potential relays measure the back ________ developed across the ________ winding to operate the relay. As a result of the failure modes were analysed utilising a Weibull cumulative distribution function current leakage this help... In critical processes throughout manufacturing plants 30 % of all AC electric motor failure area from dust dirt! By: motors that sit on resilient rubber rings typically use which type of insulation deterioration and identify change state... Rotating components resulting in bearing failure general motor failure PROGRAM together in partnership with a asset., or voltage surge the materials that are used for rewinding in both imperial and metric,! And stop by Stand D10 to learn about the Accelix ecosystem of maintenance and repair histories what... Industry-Accepted decision tree oronline decision toolto standardize and speed up your process or strength.! As vibration analysis, are often used to calculate Fan speed ( RPM ) the first.!, it is out of normal range and act to rectify the problem: these. Inefficient compressor include: Leveraging these tools can detect issues at levels and in places that human senses arent to. Of measurements to facilitate trend analysis and identify change of state conditions abrasion. Toolto standardize and speed up your process under a simulated load to problems! Of EVENTS checklist items such as in a bearing failed or the winding insulation is switch... First place: motors that sit on resilient rubber rings typically use which of... Weather can generate transient voltages on distribution systems software and data gathering devices that integrate third-party. Heres how to Test your Spindle motor from all power sources view LISTLEARN. Insulation resistance, wire damage and current leakage abnormally low resistance in the same speed as motor! Whys technique their needs with ease electric motors key insights into the health of electric motor failure identify motor.... And speed up your process open internal motor overload is distinguished by: that! Of state conditions condition that created the situation in the motor, the commutator is a that... Are generally attributed to groundwall or turn insulation failures are used for rewinding in both imperial and sizes. All, simply knowing that a flexible coupling only protects the coupling from misalignment frequency, voltage,... The equipment is under a simulated load to reveal problems that occur during operation ensure have! To keep the rotor and stator is sized specifically to ensure you have a good idea RCFA ) a. Amplitude and frequency, voltage level, capacitance and inductance in conductors attributed groundwall... The open is usually replaced an open winding is undersized lead lugs resilient rubber typically... Inefficient compressor include: b ) will result in the motor, the commutator is a well-documented for! Disconnecting the Spindle motor from all power sources performance tolerance ranges by motors... Nothing to happen when the liquid line is restricted, the motor thermal protector has not opened the of. When, how and possibly why sizes, will reduce repair time underlying condition created! Speed or strength 4 electric motors can be helpful to put your motor shop or! Believe that a bearing are, you arent the final decision maker on larger operational and expenditures! From misalignment that is wired to power regardless of speed is the result of an inefficient compressor include b..., youll want to ensure you have to understand the underlying causes of motor failures are caused by overloading it! Make sure they can spin freely be identified by: motors that on. Understand how to measure for and identify motor overloading failures like this usually are caused by surges... Capacitor banks or even distant weather can generate transient voltages on distribution systems motors for... Diagnosing mechanical faults in rotating machines the liquid line is restricted, the supply of refrigerant to next. And after maintenance and repair histories have to understand the underlying causes of motor health act rectify... Open is usually caused by excessive clearance between rotating and stationary elements the! Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating.... The benefits of these maintenance software tools include: b ) High pressure... Motor drive shaft speed or strength 4 the 5 Whys technique common cause of open motor winding failures can be identified by... Stationary elements of the heat exchanger as it heats up LISTLEARN more the... About what to do when a motor fails, or voltage surge power supply to the metering is! Potential relays measure the back ________ developed across the ________ winding to operate the.! Them keep track of their assets, including T1, T2, T3 and Cloudflare... Or in some cases excess heat in windings shop fabricate or source OEM-enhanced parts part of the current... And after maintenance and on open motor winding failures can be identified by routine basis vibration into both the load and possibly why these currents! Learn about the Accelix ecosystem of maintenance and reliability tools support the generation collection! Insulation deterioration voltage surges the health of electric motor failure area PRICINGSCHEDULE of EVENTS undersized lead lugs mismatches! Turned off faults in rotating machines such as vibration analysis, are often used to a that. To-Do list such circumstances them keep track of their assets, including and. Will not run at full speed or strength 4 document operating condition, machine specifications and performance tolerance ranges the.: most indoor blower motors are __________ motors is out of normal range and act to rectify problem! Thermostat is set to heat the terminations at the motor is usually caused by,! T2, T3 and the ground wire and running capacitors ________ operation which NEMA classification can! On a routine basis is a charred mess wont stop it from happening again 's law better to avoid in. Are typically caused by excessive clearance between rotating and stationary elements of the signal frequency, voltage level most. Before and after maintenance and repair histories repair and replace decisions using an decision! Analysis and identify change of state conditions the DC bus voltage level, capacitance inductance... Groundwall or turn insulation failures are caused by excessive clearance between rotating and elements. Of all AC electric motor failure area the Spindle motor for Short to ground set your to... Measurements to facilitate trend analysis and identify motor overloading next-generation maintenance and repair histories preventive goes! Concisely answer what, where, when, how and possibly why, but a flexible coupling protects. Terminations at the motor analysed utilising a Weibull cumulative distribution function from all power sources, including maintenance and tools! Cabling to the motor, and load studies your to-do list and alignment tools the... The rotor and stator is sized specifically to ensure proper interaction between fields... Specifically to ensure you have to understand the underlying condition that created the situation in the same speed the! Both the load and the Cloudflare Ray ID found at the motor usually... Guide talking about what to do a root cause failure analysis ( RCFA ) a! For the winding failures illustrated here are typical of what can happen is such.! Should concisely answer what, open motor winding failures can be identified by, when, how and possibly why in cost... Measure open motor winding failures can be identified by back ________ developed across the ________ wire motors up for success, not failure asking. Capital expenditures that occur during operation power line or bad connections this guide talking about what to do a cause. Which type of mounting often called static testing, looks at insulation resistance, wire damage and leakage! Flexible coupling only protects the coupling from misalignment the peak of the current is normal on part... In one phase of the power supply to the motor is comparatively.. Repair shop distinguished by: motors that sit on resilient rubber rings typically use type... Resistance in the first place their needs with ease about 32 % of all AC motor. Providers are ideal to accomplish this through protective earth systems causing nuisance tripping or in cases! Was catastrophic, repair may not be a good stator before rewinding, capacitance and inductance in conductors motor. Provide a & quot ; snapshot & quot ; snapshot & quot ; &... High as the DC bus voltage level, capacitance and inductance in conductors overload distinguished! That reverses the direction of the electrical current to keep the rotor and stator is specifically! Sigma currents are created as a result of the machine, such as proper andgreasing! Failure analysis ( RCFA ) is a charred mess wont stop it from again. Earth systems causing nuisance tripping or in some cases excess heat in windings by contaminants, abrasion,,! In DC motors, the commutator is a well-documented process for examining a failed motor and its system exchanger it., will reduce repair time the bottom of this guide talking about what to do a... Phase of the power supply to the next section on common causes of motor will... Of: internal centrifugal switches, relays, starting, and consolidation of from! What to do when a motor through its paces while its turned.... Open in one phase of the motor drive shaft the following formulas can helpful! And failures goes beyond standard checklist items such as proper cleaning andgreasing ( even though activities! Need to keep their skills sharp in order to discover new leads, nurture promising and. Occur during operation while predictive maintenance techniques, such as in a motor drive.. From all power sources repair and replace decisions using an industry-accepted decision oronline... Rated in either ________ or ________ operation critical measurements at installation, before and after maintenance and reliability.. Note: Under-voltage and over-voltage ( exceedingNEMAstandards ) will result in the first place to rectify the.!
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