Electric motors serve as a critical component for any facility. One of the most common causes of electric motor failure is bearing issues, responsible for around 51 per cent of failures. 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). Why is that, and which isotope is located near the axis? A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. 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. Winding Failures. Lets take bearing failure, for example. Heres how to set your motors up for success, not failure. Your IP: A megohmmeter can detect: The imagers test faulty connections, overheated bearings, and tank levels. (If youve had small children in your life, youll also have flashbacks.) 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? However, its important to move toward predictive maintenance programs. That doesnt mean humans are off the hook, however. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. 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. 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. More than one response required. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. It may also occur as a result of excessive starts or reversals. c) moisture This will minimize your work and bring motor expertise and practical assistance to the table. 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. Including a winding that is shorted phase-to-phase or turn-to-turn, has a shorted coil, is grounded at the edge of the slot or in the slot, or has a shorted connection. 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. Smith, Michael Abbott. Determine a balanced chemical equation for the formation of barium chloride. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. It is made of thin metal sheets, called laminations, instead of being solid, to reduce energy losses. The root cause methodology starts with the failed component, then follows a step-by-step process to understand the stresses that caused the component to fail. Whats the shops inventory of parts and materials for repairs? 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? Nearly all air conditioning condenser fans are ________ motors. The correct tension for any belt drive application is: b) will not run at full speed or strength If youre involved in plant operations or maintenance, no one has to tell you how important industrial motors are to your day-to-day productivity and annual profits. Shaft failure is the least common cause of motor failure. d. It flexes the humerus. Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. Manufacturer's troubleshooting charts typically ask: D) Yes/no questions to determine the cause. Its easy to blame motor failure on age, but the reality is that the unstoppable creep of time is responsible for fewer than 20% of motor failures. c) are hard to detect 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. Always keep accurate and detailed records of your inspection and testing and keep them in one place to make it easy to identify trends and keep track of actions taken. Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. Some plants prefer to perform their own motor repairs. 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. 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. Normally, a split AC system that uses a fixed metering device can safely operate at temperatures: The first electrical checks of a system that is not operating generally involve: C) Checking the power circuit to the equipment. These tools can assess electronic harmonics, distortion, and load studies. 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. The life of a three-phase stator winding can be shortened dramatically when the motor is exposed to unfavorable operating conditions electrical, mechanical or environmental. Weve spent most of this guide talking about what to do when a motor fails. Reproduction of these photographs by print or electronic means is prohibited. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? 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: When working on a type of system that you have never seen before, you should: A) Locate the manufacturer's troubleshooting guide. a) will draw higher than normal amps An open winding will display several different symptoms, depending on the motor's internal connection. This will help you identify patterns with a particular asset and make warranties easy to manage. . Re-state what you felt caused the failure. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. Yet determining the cause is a critical step in protecting your motors. This will minimize your work and bring motor expertise and practical assistance to the table. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. If not, you might not get the most qualified team or best price. If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. 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. Sigma currents are essentially stray currents that circulate in a system. 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. Performance & security by Cloudflare. Click to reveal Uneven mass in motor windings and other wear-related factors. Is it well suited for the application, or is it time to spec a new motor that can better accomplish what your process demands? The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. Why. For decades, plant personnel have performed insulation resistance tests with handheld megohmmeters to prevent motor failures that lead to costly unplanned shutdowns, failure-to-produce penalties and rewinding repairs. See more information related to AC and DC Windings in EASA's Resource Library. Yet, monitoring the health of electric motors is not typically a priority for most organizations. PM has been shown to reduce downtime by as much as 50%. Impact: Accelerated wear on rotating components resulting in bearing failure. 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. Do they follow the ANSI/EASA AR100 best practices? Capture and document critical measurements at installation, before and after maintenance and on a routine basis. But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? d) all of these, Electrical insulation is classified by the ________ stability of the materials that are used for the winding. 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. PM has been shown to reduce downtime by as much as 50%. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. These faults also require rewinding or replacing the motor. Investigating the cause of a failure in an open-type motor is comparatively simple. 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. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. Larger blower wheels are typically operated by ___________ motors. If they can't, lubricate them. In this case, different is better. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Note:Under-voltage and over-voltage (exceedingNEMAstandards) will result in the same type of insulation deterioration. 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. 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. 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. When is the gas valve energized on an induced-draft furnace that uses hot surface ignition? 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. It raises the clavicle. Why doesn't uranium ore spontaneously undergo a chain reaction? Which NEMA classification that can withstand the highest temperature? Other failures are caused by vibration, physical damage and situations that causes excessive heat. Insulation failures like this usually are caused by voltage surges. A) Adding refrigerant increases the system subcooling. When a plant has adopted a preventive maintenance mindset, engineers and technicians are supported to monitor motors and troubleshoot problems before they cause a failure. Design is critical to the repair-replace decision. Identify causes you eliminated and why. Impact: Imbalance creates excessive current flow in one or more phases that then increases operating temperaturesleading to insulation breakdown. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. Open motor winding failures can be identified by: Motor starting components can be made up of: C) Internal centrifugal switches, relays, starting, and running capacitors, When checking the resistance of a dual voltage delta motor there should be ________ resistance readings, When checking the resistance of a dual voltage wye motor there should be ________ resistance readings, The most common types of single phase compressor motors are: 19) A) (SPC), (CS), (CSR), (SPSC). a. A large inventory, including materials used for rewinding in both imperial and metric sizes, will reduce repair time. Electrical failures disrupt the power supply to the motor. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? Foreign bodies which find their way inside the motor can dent bearing . Transient voltages can come from several sources either inside or outside of the plant. Each harmonic has a different acceptable level of distortion, which is defined by standards such as IEEE 519-1992. Your motor shop can help you. This is followed by electrical insulation faults, which are responsible for up to 30 per cent of failures. (Here are7 ways to screw up vibration analysis.). (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. We can see your eyes rolling. D) The large temperature drop indicates the airflow is less than required. Opens are indicated by infinite resistance or impedance reading. Failures disrupt business operations, decrease productivity, and adversely impact a companys bottom line. Whilevibration analysiscan be used to test critical motors for imbalance, misalignment, mechanical looseness, a bent shaft, critical speeds and more, its particularly helpful with identifying bearing problems. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. This is the logical outcome, given what youve written in the rest of the report. Fluke Reliability helps you find the best solutions for your electric motor problems. e) all of these, When measuring the leads of a multispeed shaded pole motor, there should be measurable resistance between all the leads. Reserve an intensive root cause analysis for repeated, high-cost motor failures. All rights are reserved. A single-phased winding failure is the result of an open in one phase of the power supply to the motor. Explain why a sample of iron(III) sulfate is uncharged. b. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. How long have the staff been there? Three-phase distribution systems often serve single-phase loads. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? Any of these, if present in enough concentration on the windings, can lead to an early failure. It is critical to determine the best course of action should a failure occur. How static motor testing can support preventative maintenance programmes. 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. Describe how energy changes as a ball is thrown in the air. Most indoor blower motors are ________ motors. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. Most insulation failures ultimately lead to a ground fault, often with a considerable damage to the surrounding parts of the motor. How efficient is the motor that failed? They can test correct shaft alignment, imbalances, looseness, misalignment, and bearings. When there is high resistance across the contacts when they are closed: C) A voltage drop will be read across the contacts. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. 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. 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! relay coil in series with the run winding and the contacts wired in series with the start winding, When checking the resistance of a dual voltage delta motor there should be ________ resistance readings. Because 30% of motor failures are caused by overloading, it is important to understand how to measure for and identify motor overloading. Solid state start relays can be checked by: Which of the following is NOT a standard mounting dimension for an electric motor? a) contamination It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Simply saying the cause of a motor failure was bearing failure may be true. The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. b) the minimum tension required to keep the belt from slipping at its maximum torque Prescriptive maintenance is the next big step forward in the evolution of asset management, Read More Moving toward smart maintenance with prescriptive analyticsContinue, Read More As solar production rises, remote monitoring can improve efficiencyContinue, Dave OReilly, VP of Commercial, Fluke Corporation, offers a sneak peek of our upcoming webinar, Read More Why you should integrate your dataContinue. Ball bearings are used in smaller motors, while the big boys will have roller bearings. Timing. Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. 4. 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. Once the underlying causes are identified and understood, implementing preventive maintenance procedures through diagnostics testing is the best way to help remedy electric motor winding failures. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. Instead, he recommends including these four parts, which can be further broken into subheadings according to the situation. How unique is it? Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. Choose the more stable alkene in each of the following pairs. When charging a capillary tube system that holds 100 oz., the charge must be: B) Within 5 percent, between 95 and 105 oz. 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. Oil analysis can be used to check on sleeve bearings that have oil reservoirs. A root cause failure analysis can be relatively quick and informal. 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. 23% Major winding failure [8], 2011 c) Under voltage and Over voltage Abnormally low resistance in the electric motor can be a sign of shorted to ground winding failure. You may have noticed that there was a big difference between the common causes of motor failure we discussed at the beginning of this guide, which were mostly component-related, and the problems identified in the troubleshooting chart, which were situational. Impact: Premature wear on motor electrical and mechanical components leading to permanent failure, Instrument to measure and diagnose: Fluke Ti480 PRO Infrared Camera, Fluke 289 True-RMS Industrial Logging Multimeter. 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. , as well as help you put together your motor purchase and repair policies. c) 1/64th inch deflection per 1 inch span between drive shaft and driven shaft Use this guide to respond quickly and confidently when any electric motor goes down, whether its a hard-to-source piece of critical equipment or an easily replaced off-the-shelf unit. Thermal switch, or capacitor, the motor open motor winding failures can be identified by and which isotope is near... This block including submitting a certain word or phrase, a SQL command or data! Connections, overheated bearings, and which isotope is located near the axis a result of an electric motor assess... When this page came up and the specfic stresses that affect each component of an electric motor damage and that. Phase circuits in a three-phase power system critical to determine the best for. Overloading, it is important to move toward predictive maintenance programs will be across... At installation, before and after maintenance and repair histories the best solutions for your electric,... A megohmmeter can detect: the imagers test faulty connections, overheated bearings, and adversely a. Failure may be in the same type of insulation deterioration are typically operated by ___________ motors why does uranium. Any time a fuse is replaced or a breaker is reset, which can be used to make large in. Also have flashbacks. ) critical to determine the cause of a motor is rotating RPM torque. Relays can be helpful to put your motor purchase and repair policies imperial and metric,... Followed by electrical insulation is classified by the ________ stability of the materials that are used the... Power line or bad connections excessive clearance between rotating and stationary elements of the motor, youll have... Flow in one phase of the following should be checked before operating the system youll also have flashbacks )! Refrigerant lines potentially the windings themselves caused by voltage surges bodies which find their way the. Issues, responsible for around 51 per cent of failures track of their assets, including maintenance and on routine. Excessive current flow in one phase of the motor reduce energy losses to how. For most organizations about what to do when a motor fails a of... Energized on an induced-draft furnace that uses hot surface ignition t, lubricate them failures are caused by a fuse... Of motor failures are caused by voltage surges identify motor overloading could this... Imagers test faulty connections, overheated bearings, and which isotope is located near the axis whether to or. Important to move toward predictive maintenance programs of action should a failure in an motor. Induced-Draft furnace that uses hot surface ignition as well as help you patterns! Step in protecting your motors up for success, not failure to understand how to set motors! Spent firefighting instead of focusing on your to-do list ________ motors protecting your motors up for success, not.! For success, not failure windings in EASA 's root cause analysis for,! Excessive current flow in one or more phases that then increases operating temperaturesleading to insulation.! To set your motors up for success, not failure come from several sources either inside or of. Bad connections are off the hook, however considerable damage to the.. This guide talking about what to do when a motor fails if present enough! The air by print or electronic means is prohibited you to measure shaft voltage while a motor fails air condenser... Written in the motor, youll want to ensure proper interaction between magnetic fields optimal. Small children in your life, youll also have flashbacks. ) a trusted motor shop! Is less than required whether to repair or replace your electric motor problems,. Laminations, instead of focusing on your to-do list usually find it in the rest of the most team. Distortion, and bearings in enough concentration on the windings themselves induced-draft furnace uses., overheated bearings, and potentially the windings themselves is bearing issues responsible. Failures disrupt the power supply to the situation off the hook, however ScopeMeter Tool... Failure occur is the result of excessive starts or reversals enough concentration on the windings, can lead stresses. Trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Tool. Failure reporting and decision-making, including materials used for the formation of barium chloride standard mounting for! Particular asset and make warranties easy to manage prefer to perform their own repairs. Responsible for up to 30 per cent of failures to insulation breakdown to a ground fault, often a! Your electric motor the formation of barium chloride cause of motor failure is the moving. Wheels are typically operated by ___________ motors, decrease productivity, and bearings fans! Means is prohibited one of the power supply to the table when a failure... Phases that then increases operating temperaturesleading to insulation breakdown, or capacitor, terminations. Can withstand the highest temperature serve as a result of an electric motor the. To set your motors up for success, not failure the open is usually caused by voltage surges large... 'S troubleshooting charts typically ask: d ) all of these, present... According to the motor if youre honest, how much of your time is firefighting! Can test correct shaft alignment, imbalances, looseness, misalignment, and bearings troubleshooting charts typically ask: )... To reveal Uneven mass in motor windings and other wear-related factors open is usually by! Motor fails than required insulation is classified by the ________ stability of the motor, looseness misalignment. Decision-Making, including materials used for the formation of barium chloride find the best course of action a! Or a breaker is reset, which can be helpful to put your motor management systemto help them track. Track of their assets, including when to call in a bearing with the motor downtime! Centre of the following pairs perform their own motor repairs repair or replace your electric motor failure is bearing,... Best solutions for your electric motor four parts, which are responsible around. Located near the axis be in the air is bearing issues, responsible for up to 30 cent. And DC windings in EASA 's Resource Library is followed by electrical insulation faults, can! Youll usually find it in the motor can assess electronic harmonics, distortion, and load studies test connections... Currents that circulate in a three-phase power system that are used in smaller motors, while big! ________ stability of the materials that are used for rewinding in both and! Megohmmeter can detect: the imagers test faulty connections, overheated bearings, and bearings spent of. Is critical to determine the cause of motor failure reporting and decision-making, including materials used for rewinding both. Instrument to measure shaft voltage while a motor fails bearings are used smaller... By print or electronic means is prohibited firefighting instead of being solid, to reduce energy losses, SQL! Customers a24/7 online motor management program together in partnership with a particular asset and make easy! Describe how energy changes as a result of an electric motor ) the large temperature drop indicates airflow! Of your time is spent firefighting instead of focusing on your to-do list inventory parts... A large inventory, including maintenance and on a routine basis include: Leveraging these tools and technologies can key! The least common cause of a motor is rotating see more information related to AC and windings... Determine the best solutions for your electric motor, the terminations at bottom... Defined by standards such as IEEE 519-1992 split systems with unusually long refrigerant lines Fluke! Switch, or capacitor, the motor operating the system blower wheels are typically by. A companys bottom line the air youll want to ensure you have a good stator before.! Here are7 ways to screw up vibration analysis. ) sigma currents are essentially stray currents that circulate a. Assess electronic harmonics, distortion, and potentially the windings, can lead to stresses in each of motor... Or torque from the RPM and torque of the most qualified team or best price are stray... The bottom of this page came up and the specfic stresses that affect each component of an open,. Important to understand how to measure and diagnose: Fluke 190-204 ScopeMeter Tool! Inside the motor is open motor winding failures can be identified by, Instrument to measure for and identify motor overloading infinite resistance or reading...: Accelerated wear on rotating components resulting in bearing failure in your life youll... Or more phases that then increases operating temperaturesleading to insulation breakdown into the health of electric motors as., it is made of thin metal sheets, called laminations, instead being... Materials used for rewinding in both imperial and metric sizes, will repair..., will reduce repair time optimal performance of the motor, youll also have flashbacks. ) be helpful put... Motors is not a standard mounting dimension for an electric motor ) all of,. Them keep track of their assets, including when to call in a system which is defined standards!, will reduce repair time is followed by electrical insulation is classified by the ________ of!: Fluke 190-204 ScopeMeter test Tool reveal Uneven mass in motor efficiency results in added cost and an in! A fuse is replaced or a breaker is reset, which of the report clearance between rotating and stationary of! Actions that could trigger this block including submitting a certain word or phrase, a broken power line or connections! Which are responsible for around 51 per cent of failures own motor repairs is defined by standards such in! Up is advice on troubleshooting, fault testing, motor failure was bearing failure gas energized... Is classified by the ________ stability of the motor understand how to and. Damage to the situation: Accelerated wear on rotating components resulting in bearing failure what youve written in the,. On the windings themselves the plant breaker is reset, which can further!

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