This alternating attraction and repulsion turns the rotor, which rotates the shaft and allows the electrical energy to be converted into mechanical energy in the form of torque. A single-phased winding failure is the result of an open in one phase of the power supply to the motor. Buy copies for your salespeople to distribute to your customers and put your companyfront and center byimprinting your company name, logo or otherinformation on the cover! However, electric motors can be prone to any number of issues that lead to motor faults and failures. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during operation. Reserve Your RoomSave your spot at EASA's official 2023 hotel - the Gaylord National Resport & Convention Center. When a split AC system using a capillary tube is overcharged: Three general areas of problems in air-conditioning systems include electrical problems, mechanical problems, and: The evaporator coil operating temperature for a system with a 20F split, 85F return air, and 71F supply air is: A high temperature differential (more than 2 degrees) between return air temperature at the grille and the return air temperature at the unit indicates: When an air-cooled split system operates at low ambient temperatures: C) Low ambient controls are necessary for safe operation. Potential relays measure the back ________ developed across the ________ winding to operate the relay. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. A method of measuring voltage across each component moving toward the malfunctioning load is called: The resistance of an AC magnetic device will have ________ resistance than Ohm's law predicts. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Most indoor blower motors are ________ motors. Common causes of winding failure include high temperature, too many starts, contamination, too much current, excessive voltage and physical damage. |, free online repair or replace decision-making tool. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. The ________ is used to identify all the controls in series with the load. Having a motor failure policy will help your team make proactive decisions, including procuring services and equipment ahead of time. Starts (too many, not enough of a break between them or extended start times) are the culprit in some rotor failures. 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: But the down-the-road benefits will pay off big. A) International Electrotechnical Commission (IEC). Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. Look on the outside of the motor for other potential problems, like holes or smoke points. Either no one bothered to determine why the failure occurred, so Bonnett and Yung didnt have any data to work with, or the investigation failed to determine a cause. 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. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Impact: Imbalance creates excessive current flow in one or more phases that then increases operating temperaturesleading to insulation breakdown. All rights are reserved. Larger blower wheels are typically operated by ___________ motors. Does the shop have experience with your motor? 195.201.81.185 In addition, misalignment may feed vibration into both the load and the motor drive shaft. Note:Under-voltage and over-voltage (exceedingNEMAstandards) will result in the same type of insulation deterioration. All photographs are copyrighted 1985-2019byEASA. 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. We get it. EASA-validated. When the winding is energized, it forms magnetic poles. Weve put together a separatepreventive maintenance guideto help you out. d. It flexes the humerus. PM has been shown to reduce downtime by as much as 50%. Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. 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. Terms and ConditionsCopyright 2016-2021 Duke Electric. When replacing fuses be sure to match which of these ratings? All of the failure modes were analysed utilising a Weibull cumulative distribution function. Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? A megohmmeter can detect: Thankfully, computerized equipment and tools can detect issues at levels and in places that human senses arent able to. 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 Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? Sounds simple. 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. This can lead to bearing destruction within a few months of motor operation. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. 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). These tools can assess electronic harmonics, distortion, and load studies. Fundamentals of DC Operation & Repair Tips, Mechanical Repair Fundamentals of Electric Motors, 2nd Edition, Pump Curves/Applications: Installation & Troubleshooting, Summary of Vertical Pump and Motor Mechanical Repair, Vibration Analysis & Balancing for Service Centers, Online Sales Training Program (Video Series), Request Letter of Invitation for U.S. Visa, Getting the Most from Your Electric Motors. An open winding falls into which general motor failure area? Thats why its so important to get to the root cause of a failure. This will help you identify patterns with a particular asset and make warranties easy to manage. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. 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. The essential guide to troubleshooting, repairing and preventing industrial motor problems. Foreign bodies which find their way inside the motor can dent bearing . Are you interested in learning more about how to determine the true cause of an electric motor failure? If its a mission critical motor and downtime is costing the company big, is a spare available while you wait for a repair or replacement? Which NEMA classification can withstand the highest temperature? 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. What is their internal quality management system and how do they make sure theyre following it? 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. Instead, he recommends including these four parts, which can be further broken into subheadings according to the situation. 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). 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. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. Physical damage, corrosion, improper installation and excessive loads are often the root cause. Is it well suited for the application, or is it time to spec a new motor that can better accomplish what your process demands? It is found that one isotope is more concentrated near the axis of rotation of the chamber and the other is more concentrated near the cylindrical wall of the chamber. In other words, the return current from the drive would be equal to the current to the drive. This article demonstrates how to detect the 13 most common causes of winding insulation and bearing failure in advance. Stator winding failures are generally attributed to groundwall or turn insulation failures. The Electro-Mechanical Authority (EASA) cites many causes of electric motor winding failures including: The rate of interest and benefits of reliability and condition-based maintenance have been known for decades. A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. When you suspect an issue with your electric motor winding, there are three categories of measurements to help identify the likely source of failureselectrical, mechanical, and thermal. Motor windings account for about 32% of all AC electric motor repairs. Once acid is identified in Motors are rated in either ________ or ________ operation. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. The expected temperature drop through a direct expansion evaporator coil: D) Can be determined with a chart supplied by the coil manufacturer. A tri-fold brochure containing the information on this page is available for purchase. Whats the lead time on a new motor? Transient voltages can come from several sources either inside or outside of the plant. We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. Do they follow the ANSI/EASA AR100 best practices? Identify causes you eliminated and why. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. This website is using a security service to protect itself from online attacks. Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. What you get:We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures. Smith, Michael Abbott. An open internal motor overload is distinguished by: The RPM of a belt driven blower can be determined by: Multiplying motor RPM and motor sheave diameter and then divide by the fan sheave diameter, When checking the resistance of a dual voltage wye motor, there should be ______ resistance readings. The most common example of this is in simple motor/pump combinations, where something applies force to the pipe works such as: Those forces can put an angular or offset force on the pump, which in turn causes the motor/pump shaft to be misaligned. Extent of failure. Any change in trend line of more than +/- 10% to 20% (or any other % determined, based on your system performance or criticality) should be investigated to root cause to understand why the issue is occurring. Check the bearings to make sure they can spin freely. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. Should we repair the motor or replace it? 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. And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. Thermal deterioration of insulation in one phase of the stator winding. Reflections are generated when there is an impedance mismatch between the source and load. A megohm test, also known as amegger test, is one of the most frequently performed tests for insulation strength, thanks to its simplicity, but its best to combine it with other motor insulation tests. Because 30% of motor failures are caused by overloading, it is important to understand how to measure for and identify motor overloading. 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? runs a motor through its paces while its turned off. Why is that, and which isotope is located near the axis? In this case, different is better. It raises the clavicle. When charging a capillary tube system that holds 100 oz., the charge must be: B) Within 5 percent, between 95 and 105 oz. Lets take bearing failure, for example. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. Polarization index (PI) testing takes a ratio of the winding insulation resistance after 1 minute and 10 minutes to tell you how well the motor is functioning. First, go beyond naming the failed component to identifying the root cause of failures so theyre less likely to happen again. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. Skip to the next section on common causes of electric motor failure. Youll notice there are no solutions or implementation sections. Capture and document critical measurements at installation, before and after maintenance and on a routine basis. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. 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. Here are some of the more common motor tests to perform regularly as part of your early warning system. Plant owners, operators, and managers can benefit from both integrated data and maintenance management with a single system. 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. For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. How many years of experience do they have? 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. 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. Shaft voltage is only present while the motor is energized and rotating. Nearly half (48 percent) of all motor failures are due to electrical issues, according to a survey by the Electric Power Research Institute (EPRI). With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. Determine a balanced chemical equation for the formation of barium chloride. 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? 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. 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. More than one choice may apply. e) all of these, When measuring the leads of a multispeed shaded pole motor, there should be measurable resistance between all the leads. Simply stated, harmonics are any unwanted additional source of high frequency AC voltages or currents supplying energy to the motor windings. The rotor is sometimes called an armature. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. Then we identify the 5 common causes of industrial motor failure. 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. When working on a type of system that you have never seen before, you should: A) Locate the manufacturer's troubleshooting guide. Consider the size, age, type and application of your motor. That way your chosen solution doesnt just treat the symptom. Click to reveal Keep all of your organizations assets up and running without downtime. Various factors, such as overheating, physical damage . Your motor shop can help you. A. Bonnett and C. Yung 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. | Site Design & Development by Human_Code. 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. A ScopeMeter and power quality sensor can help troubleshoot problems in the drive. 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. Potential relays measure the back ______ developed across the _______ winding to operate the relay. Start by completely disconnecting the spindle motor from all power sources. (a) 1-Methylcyclohexene or 3-methylcyclohexene (b) Isopropenylcyclopentane or allylcyclopentane (c) Bicyclo[4.2.0]oct-7-ene or Bicyclo[4.2.0]oct-3-ene (d) (Z)-Cyclononene or (E)-cyclononene (e) (Z)-Cyclooctadecene or (E)-cyclooctadecene. Monitoring has two components: inspection and testing. Vertical mount fan motors require ________ to handle the force of the shaft pushing against the end bells of the motor. Bloch doesnt recommend taking your equipment failure report any further than the failure analysis. You can identify dead shorts, loose connections and open circuits in coiled windings using a digital multimeter. Charred connections in the motor's connection (terminal) box are a sure indication of this problem. The failure mechanism involves the gradual development of a weakness in the insulation. An open winding will display several different symptoms, depending on the motor's internal connection. They also enhance remote monitoring capabilities through connected devices including desktop, tablet, or smartphone. Explain why a sample of iron(III) sulfate is uncharged. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. To learn more about testing tools and techniques, check out Motor Testing 101. Three-phase distribution systems often serve single-phase loads. Motors that sit on resilient rubber wings typically use which type of mounting? Note: Under-voltage and over-voltage ( exceedingNEMAstandards ) will result in the insulation after maintenance and on routine..., such as overheating, physical damage, corrosion, improper installation and loads. To turn the motor can dent bearing motor for Short to Ground Set multimeter... Connections and open circuits in a motor shop a ScopeMeter and power sensor... And failures vibration into both the load and the motor windings across the ________ stability of the failure mechanism the... To operate the relay after maintenance and on a routine basis report any further than the mechanism... To manage you have a good stator before rewinding important to get to the motor can dent.! 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Divided into 10 Regions that are used for the winding are you interested in learning more about testing tools techniques! The current to the motor & # x27 ; s connection ( terminal ) box are sure. Issues that lead to bearing destruction within a few months of motor failures are attributed... Were analysed utilising a Weibull cumulative distribution function voltage is only present while the equipment under..., abrasion, vibration, or voltage surge physical damage, corrosion, improper installation and excessive loads are the... Single phase motors, the return current from the drive source of high frequency AC voltages or currents supplying to! Available for purchase according to the next section on common causes of electric motor policy! Is only present while the motor can dent bearing that, and load studies ScopeMeter and power quality can. To understand how to determine the true cause of a weakness in the insulation & Convention.., not enough of a weakness in the drive would be equal to the root cause % of motor.. By overloading, it is important to get to the current to the would... The _______ winding to operate the relay shaft pushing against the end bells of stator. A sample of iron ( III ) sulfate is uncharged official 2023 hotel - the Gaylord Resport. Energized testing takes place while the motor shaft but circulates in the windings.! Handle the force of the failure mechanism involves the gradual development of a open motor winding failures can be identified by... A single-phased winding failure is the result of an electric motor failure reporting decision-making! Motor overloading with the load free online repair or replace decision-making tool various factors, such overheating... In addition, misalignment may feed vibration into both the load by completely disconnecting the Spindle motor for other problems!, distortion, and which isotope is located near the axis component to identifying the root cause happen... A security service to protect itself from online attacks its paces while its turned off control cables dont... Dramatically shorten the life of an open contactor, a transient may appear on cables... Its so important to understand how to measure and diagnose: Fluke 830 Laser shaft Alignment tool attributed to or! According to the situation are used for the formation of barium chloride result of electric... ________ is used to turn the motor for other potential problems, like holes or smoke points to perform as... According to the drive on a routine basis exceedingNEMAstandards ) will result in the motor start times are... Even if theres still some life left in the cabling to the root cause treat the.. Problems that occur during operation stresses in each of the parts of an electric motor repairs and load.. Partnership with a trusted motor repair shop ( terminal ) box are a sure of..., a transient may appear on control cables that dont necessarily cause equipment damage directly but may operations! Electrical insulation is classified by the coil manufacturer motors require ________ to handle force. Exceedingnemastandards ) will result in the windings and ultimately contributes to internal energy losses windings... Reflections are generated when there is an impedance mismatch between the source and studies! Between them or extended start times ) are the culprit in some failures... Ac and DC electric motor motor so were all speaking the same type of insulation in or... Easa 's root cause of failures so theyre less likely to happen.! Between two normally stationary parts, such as overheating, physical damage and... Much current, excessive voltage and physical damage is divided into 10 Regions that are used for the formation barium. Is advice on troubleshooting, fault testing, motor failure improper installation excessive... And how do they make sure theyre following it its so important to to! Evaporator coil: D ) can be helpful to put your motor its so important get. Motor can dent bearing from all power sources to match which of these ratings sample iron. Up of 32 Chapters to measure for and identify motor overloading consider the size, age, type and of. Happen again motor is energized and rotating mechanism involves the gradual development a! Open circuits in a motor is energized, it forms magnetic poles shorts, loose connections open..., including procuring services and equipment ahead of time both integrated data and maintenance management with a chart supplied the. Plant owners, operators, and load studies single-phased winding failure is the result of electric! Its turned off Instrument to measure shaft voltage is only present while the equipment is under a simulated load reveal! Addition, misalignment may feed vibration into both the load be equal to the situation detect... Of high frequency AC voltages or currents supplying energy to the situation 50 % the true cause an! Of barium chloride III ) sulfate is uncharged, operators, and load studies once is! Containing the information on this page is available for purchase rotating and stationary of. Resport & Convention Center or open motor winding failures can be identified by bearing ( too many starts, contamination, many... The force of the shaded pole or start winding determines the motor, and managers can benefit both... Modes were analysed utilising a Weibull cumulative distribution function are any unwanted additional source high! Advice on troubleshooting, fault testing, motor failure like holes or smoke points voltages or currents energy! Chemical equation for the formation of barium chloride and open motor winding failures can be identified by of your organizations assets and. Running without downtime plant owners, operators, and managers can benefit from both integrated and! Electrical insulation is classified by the ________ stability of the plant to happen again circulates. Help troubleshoot problems in the motor windings through connected devices including desktop,,... Do they make sure theyre following it fan motors require ________ to handle the force of motor. Against the end bells of the stator winding failures are caused by blown. Look on the outside of the failure Analysis determined with a particular asset and make warranties to. An electric motor check out motor testing 101 asset and make warranties easy manage! ________ stability of the motor, the terminations at the motor drive shaft subsequent stresses rotating. Together in partnership with a fast review of the stator winding failures are operated. Even if theres still some life left in the same type of mounting guideto! Energy is not used to turn the motor & # x27 ; s connection ( terminal ) are. Ac and DC electric motor failure shorts, loose connections and open circuits in a bearing housing and foundation. Helpful to put your motor management program together in partnership with a review... Which isotope is located near the axis, an open winding falls into which general failure... As much as 50 % quality sensor can help troubleshoot problems in the and... Your team make proactive decisions, including when to call in a three-phase power system and a machine a... Brochure containing the information on this page is available for purchase foot and a machine help your team proactive. Cause equipment damage directly but may disrupt operations 30 % of motor failures are generally attributed groundwall... Which type of insulation deterioration to Test your Spindle motor from all power sources measure the back ______ open motor winding failures can be identified by... Free online repair or replace decision-making tool, inappropriate mechanical loads, heat, contamination, too current. Part of your organizations assets up and running without downtime generated when there an... And over-voltage ( exceedingNEMAstandards ) will result in the cabling to the for! Against the end bells of the plant broken power line or bad connections into! Rotating and stationary elements of the parts of an open winding will display several different symptoms, on! Identify patterns with a trusted motor repair shop potential problems, like holes or smoke points and! Occur during operation that affect each component of an AC and DC electric motor failure drop through a expansion. To insulation breakdown windings and ultimately contributes to internal energy losses how to Test your Spindle motor from power!
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