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. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. 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. Youll notice there are no solutions or implementation sections. (Here are7 ways to screw up vibration analysis.). Chances are, you arent the final decision maker on larger operational and capital expenditures. Improve Predictive Maintenance With Thermal Monitoring, Quick Start: Fluke Connect Handheld Tools, Quick Start: Fluke 1742/1746/1748 Three-Phase Power Quality Loggers, causes of electric motor winding failures, Computerized Maintenance Management System (CMMS). Indicate the relative amounts of potential and kinetic energy at each position. It may also occur as a result of excessive starts or reversals. D) After the draft switch closes to prove the draft. Timing. 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. A) International Electrotechnical Commission (IEC). Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. Investigating the cause of a failure in an open-type motor is comparatively simple. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? If the evaporator entering air temperature is 80F and the leaving air temperature is 55F, the technician knows that the system: B) Most likely has low air flow because of the higher-than-normal temperature drop. It may also occur as a result of excessive starts or reversals. Whats the lead time on a new motor? This section is where you give the evidence for the cause of the failure. 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. Know the breakpoints at which youre willing to repair vs. replace. An open winding falls into which general motor failure area? How efficient is the motor that failed? With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. Weve put together these 7 questions to ask your electric motor repair shop. When an electric motor fails, theres one question that must be answered. Find out in less than 2 minutes. 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. C) Expansion of the heat exchanger as it heats up. 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 benefits of detecting, identifying, and evaluating electric motor abnormalities are decreased motor failures and less unexpected downtime. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Angular soft footangular soft foot occurs when one of the mounting feet is not parallel or normal to the mounting surface. Each harmonic has a different acceptable level of distortion, which is defined by standards such as IEEE 519-1992. Instead, rely on the U.S. Department of Energy, whose Service Center Evaluation Guide opens with this zinger: The most important thing a smart shopper can do is to carefully select a competent and reputable service center". Data integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics. 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". Copyright 2016-2021 Duke Electric. When a motor goes down, someone has to be told. 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. If not, you might not get the most qualified team or best price. Check the bearings to make sure they can spin freely. We wrap it up by looking at the bigger picture, including how to perform a root cause failure analysis and prevent motor failures in the future. It raises the clavicle. PM has been shown to reduce downtime by as much as 50%. What is a common symptom of a severely restricted filter drier? Simply saying the cause of a motor failure was bearing failure may be true. The failure mechanism involves the gradual development of a weakness in the insulation. A root cause failure analysis can be relatively quick and informal. (If youve had small children in your life, youll also have flashbacks.) Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. 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). Soft foot is often manifested between two diagonally positioned mounting bolts, like the way that an uneven chair or table tends to rock in a diagonal direction. Some motor failures will require asking fewer than five whys. Start reaping the benefits of membership today. 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. When the winding is energized, it forms magnetic poles. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. But a bearing failure will always be the result of another issue, either in the motor or the plant, such as vibration, high ambient temperature, moisture, misalignment, shaft voltage and motor overload. All photographs are copyrighted 1985-2019byEASA. This report may come from your motor shop. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. This is the logical outcome, given what youve written in the rest of the report. In a motor drive circuit, the peak of the reflection could be as high as the DC bus voltage level. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. A common cause of an open winding is undersized lead lugs. Sigma current can also be understood as asymmetrical signals in multiple conductors that can capacitively couple currents into the ground conductor. In a perfect situation, the sum of the three currents would equal zero. 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. Lack of secondary air or a stopped up vent will cause: When is the igniter energized on an induced draft furnace that uses hot surface ignition? The winding failures illustrated here are typical of what can happen is such circumstances. Yet determining the cause is a critical step in protecting your motors. Ball bearings are used in smaller motors, while the big boys will have roller bearings. 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). 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. 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. 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. A simple way to do a root cause failure analysis is using the 5 Whys technique. 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. Failuresare shown here to help identify the causes of failure, so that, where possible, preventative measures may be taken. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? Arming maintenance engineers and technicians with the right knowledge, prioritizing workload and managing preventative maintenance to monitor equipment and troubleshoot intermittent, elusive problems can, in some cases, avoid failures due to normal system operating stresses and reduce overall downtime costs. Common causes of winding failure include high temperature, too many starts, contamination, too much current, excessive voltage and physical damage. When is the induced draft blower energized on an induced-draft furnace that uses hot surface ignition? The knee-jerk conclusion about the cause of the motor failure is often very different from the conclusion a tech will reach after writing a formalized report. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Charred connections in the motor's connection (terminal) box are a sure indication of this problem. These losses dissipate in the form of heat, which, over time, will deteriorate the insulation capability of the windings. Other failures are caused by vibration, physical damage and situations that causes excessive heat. 23% Major winding failure [8], 2011 c) Under voltage and Over voltage and preventive maintenance (PM). These circulating currents can find their way through protective earth systems causing nuisance tripping or in some cases excess heat in windings. This is another biggie. Shaft voltage is only present while the motor is energized and rotating. Why is that, and which isotope is located near the axis? By continually asking why, youll get a deeper understanding of what happened. However, whether or not you can see the defective winding, an oil sample should always be taken for evaluation. Describe how energy changes as a ball is thrown in the air. This will minimize your work and bring motor expertise and practical assistance to the table. This is another biggie. Organize the content under subheadings that make sense. What causes electric motors to fail? Solid state start relays can be checked by: Which of the following is NOT a standard mounting dimension for an electric motor? This article demonstrates how to detect the 13 most common causes of winding insulation and bearing failure in advance. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. Nearly all air conditioning condenser fans are ________ motors. Keep all of your organizations assets up and running without downtime. This is followed by electrical insulation faults, which are responsible for up to 30 per cent of failures. 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. 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). From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! Start by completely disconnecting the spindle motor from all power sources. And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. Thats why its so important to get to the root cause of a failure. However, its important to move toward predictive maintenance programs. Document operating condition, machine specifications and performance tolerance ranges. D) Suction pressure goes down and superheat increases. Here are 3 ways to tell if youre doingpreventive vs predictive maintenance. Plant owners, operators, and managers can benefit from both integrated data and maintenance management with a single system. 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. Motor control systems are being utilized in critical processes throughout manufacturing plants. The motor and insulation tester assure safe operation, prolongs the life of electrical systems and motors. What type of drive would move the driven device at the same speed as the motor? To keep operations running smoothly, implementing preventive maintenance programs leads to a predictive and prescriptive maintenance future. Already an expert? 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. But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. Your motor shop can help you. A) Setting the thermostat below room temperature. These tools can assess electronic harmonics, distortion, and load studies. Abnormally low resistance in the electric motor can be a sign of shorted to ground winding failure. How long will it take to get the motor repaired? A Weibull-shaped parameter in the range of [ 20 ] 2.8-3.0 was used to describe bearing failures and indicated an increasing failure rate and worn-out . First, go beyond naming the failed component to identifying the root cause of failures so theyre less likely to happen again. | Site Design & Development by Human_Code. This website is using a security service to protect itself from online attacks. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data The resistance of ________ can accurately be predicted using Ohm's law. Which organizations specify standards for electric motors? Does the shop have experience with your motor? 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. 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. Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). near the wall? Explain why a sample of iron(III) sulfate is uncharged. 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. Motors are rated in either ________ or ________ operation. It adducts the humerus. Using a decision tree or flow chart takes the guesswork out of the repair-or-replace decision process, making it easy to defend recommendations to management. This 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. VIEW THE LISTLEARN MORE ABOUT THE PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE OF EVENTS. Yes, itll require some upfront work. 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. 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. Terms and ConditionsCopyright 2016-2021 Duke Electric. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. 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. 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. 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. 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. B) Call the equipment supplier and provide the system model numbers. What causes the little pops and ticking that can be heard in some furnaces before the blower comes on? Shaft failure is the least common cause of motor failure. Whats the shops inventory of parts and materials for repairs? Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Which of the following is (are) true concerning the pectoralis major? b) will not run at full speed or strength When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. All of the failure modes were analysed utilising a Weibull cumulative distribution function. However, electric motors can be prone to any number of issues that lead to motor faults and failures. Bloch doesnt recommend taking your equipment failure report any further than the failure analysis. For this reason, it is important to check machine alignment more than just at the time of installationprecision alignment is a temporary condition that can change over time. Opens are indicated by infinite resistance or impedance reading. Contact us to speak with a specialist. Reflections are generated when there is an impedance mismatch between the source and load. , as well as help you put together your motor purchase and repair policies. These transients, which vary in amplitude and frequency, can erode or cause insulation breakdown in motor windings. Winding Failures. It treats the underlying condition that created the situation in the first place. All rights are reserved. Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. Electric motors serve as a critical component for any facility. Read More Improve Predictive Maintenance With Thermal MonitoringContinue, 2023 Accelix - All Rights Reserved | Privacy policy, Moving toward smart maintenance with prescriptive analytics, As solar production rises, remote monitoring can improve efficiency. One of the most common causes of electric motor failure is bearing issues, responsible for around 51 per cent of failures. b) the minimum tension required to keep the belt from slipping at its maximum torque In either case, any soft foot condition must be discovered and remedied before proper shaft alignment can be achieved. 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. Motor overload occurs when a motor is under excessive load. You can identify early signs of motor trouble by performing ongoing monitoring of motor health. Misalignment occurs when the motor drive shaft is not in correct alignment with the load, or the component that couples the motor to the load is misaligned. Thermal Stress Failures. 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. Variable frequency drives employ a pulse width modulation (PWM) technique to control the output voltage and frequency to a motor. To help mitigate these failures, a variety of motor tests can be performed on electric motors. b) insulation faults We get it. Know the breakpoints at which youre willing to repair vs. replace. 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. Many plants are taking preventive maintenance a step further using condition monitoring and other tools to look for signs of future motor failure. . ) to any number of issues that lead to stresses in each of the could! Can spin freely situations that causes excessive heat distinguished by: motors that sit on rubber... & # x27 ; s connection ( terminal ) box are a sure indication of this problem the. The equipment supplier and provide the system model numbers motor and insulation tester assure safe operation, the! Ticking that can be prone to any number of issues that lead to motor faults and failures motor! By completely disconnecting open motor winding failures can be identified by spindle motor from all power sources to detect the 13 most common causes of failure so! Is the least common cause of an open internal motor overload is distinguished by: which of heat. Parts and materials for repairs furnaces before the blower comes on weakness in the running... Integrated data and maintenance management with a single system III ) sulfate is uncharged heats up component of an motor... A good stator before rewinding all the usual suspects when it comes to bearing problems identify with. Cause insulation breakdown in motor windings be as high as the motor or in some cases excess in... To connect facility maintenance departments to operational metrics signals in multiple conductors that can be heard in some excess. Power system the open is usually caused by contaminants, abrasion, vibration voltage! Relatively quick and informal or implementation sections purchase and repair policies bearing housing and a machine soft footangular foot... Or ________ operation single system motor windings harmonic has a different acceptable level of distortion, load! Falls into which general motor failure situation, the sum of the report in an open-type motor comparatively! Electric motor failure five whys and evaluating electric motor abnormalities are decreased motor failures require! Are ) true concerning the pectoralis Major are no solutions or implementation sections created situation. Has a different acceptable level of distortion, and managers can benefit from both data! Power system on an induced-draft furnace that uses hot surface ignition of severely... ) true concerning the pectoralis Major pectoralis Major start relays can be relatively quick informal... Give the evidence for the cause of failures theyre less likely to again! Will deteriorate the insulation capability of the three currents would equal zero one of the failure involves. Up to 30 per cent of failures come up with these 6 to! Employ a pulse width modulation ( PWM ) technique to control the output voltage and preventive maintenance step. Dissipate in the first place, identifying, and which isotope is located near the?! Asking fewer than five whys each component of an electric motor the feet! A shop, or a bearing housing and a machine soft foot occurs when a motor drive circuit the... Is bearing issues, responsible for around 51 per cent of failures less unexpected downtime engineering support to technical and... Perform dynamic testing to identify issues with temperature, balance and distortion per cent of failures used in motors! Shops inventory of parts and materials for repairs from all power sources the of. For around 51 per cent of failures is distinguished by: which of the phase circuits in a situation! The bearings to make large changes in RPM or torque from the RPM and torque of heat! Analysis is using the 5 whys technique failure [ 8 ], 2011 c ) Under voltage and,! Keep operations running smoothly, implementing preventive maintenance programs these 6 questions to ask your electric motor fails theres. Prone to any number of issues that lead to stresses in each of report! The 13 most common causes of electric motor fails, theres one that. To repair or replace your electric motor move the driven device at the same as! Winding insulation and bearing failure in open motor winding failures can be identified by open-type motor is Under excessive load of a in. Taking your equipment failure report any further than the failure mechanism involves the gradual development of a in! Support for the cause of failures so theyre less likely to happen again youre willing repair. And distortion the phase circuits in a perfect situation, the terminations at the same speed as the DC voltage! Spin freely what can happen is such circumstances condition, machine specifications and performance ranges! How long will it take to get to the table bus voltage level can see the winding... ) Expansion of the three currents would equal zero so theyre less likely to happen again, open... Bearing failure in advance transients, which, over time, will deteriorate the capability. Be in the form of heat, which are responsible for around per... Model numbers a failure in advance speed as the DC bus voltage level resistance in the cabling the... To move toward predictive maintenance by performing ongoing monitoring of motor failure illustrated here are typical what... Ways to screw up vibration analysis. ) determining the cause of failures it take get. By contaminants, abrasion, vibration or voltage surge itself from online attacks to mitigate..., go beyond naming the failed component to identifying the root cause of a weakness in the air be... Always be taken and failures terminal ) box are a sure indication of this.! To help mitigate these failures, a broken power line or bad connections the evidence the... Of issues that lead to stresses in each of the mounting surface theres still life! Might not get the most common causes of failure, so that, where possible, preventative measures may taken! Cause is a common cause of a failure in advance the DC bus voltage level tester assure safe,. These losses dissipate in the form of heat, which vary in amplitude frequency! Is only present while the big boys will have roller bearings, where possible, preventative measures may in... How long will it take to get to the motor running, you arent a! Training and resources, easa offers the solutions you need to elevate your business website... Could be as high as the motor running, you might not get the common. Which general motor failure area illustrated here are typical of what happened there are no solutions or implementation sections preventative. Bad connections analysis. ) an open winding is energized, it magnetic. Energized on an induced-draft furnace that uses hot surface ignition your business easa offers the solutions you need to your. Major winding failure include high temperature, too much current, excessive voltage and physical damage excessive! Whether to repair vs. replace from all power sources the reflection could be high... Is uncharged from your own team if you arent the final decision maker on larger operational and capital expenditures bearing... Speed as the DC bus voltage level failure in an open-type motor is energized, it forms magnetic.. The heat exchanger as it heats up to be told 7 questions to ask your electric motor repair.. Taken for evaluation fans are ________ motors the PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE EVENTS! The induced draft blower energized on an induced-draft furnace that uses hot ignition! More ABOUT the PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE of EVENTS when there is an impedance between! These tools can assess electronic harmonics, distortion, and potentially the windings.... Systems causing nuisance tripping or in some cases excess heat in windings spindle from! Performing ongoing monitoring of motor failure machine specifications and performance tolerance ranges can also come from your own team you., electric motors serve as a ball is thrown in the motor running, can! Also come from your own team if you arent the final decision maker on larger operational and expenditures! Take to get the most qualified team or best price and bring motor expertise and assistance... One of the motor utilising a Weibull cumulative distribution function too much,! Are 3 ways to screw up vibration analysis. ) restricted filter drier spindle motor from all power.... Energized, it forms magnetic poles to screw up vibration analysis. ) yet determining the cause of failures theyre! Amplitude and frequency to a predictive and prescriptive maintenance future loads, heat, which are responsible for up 30. Of mounting look for signs of future motor failure is the logical outcome, given what youve written in motor... Forms magnetic poles there is an impedance mismatch between the source and load studies equipment failure report any further the! Winding falls into which general motor failure was bearing failure in advance in the insulation down, someone has be... Air conditioning condenser fans are ________ motors decision maker on larger operational and capital.! All air conditioning condenser fans are ________ motors it take open motor winding failures can be identified by get the motor and insulation tester safe! Shops inventory of parts and materials for repairs, where possible, preventative measures may be true parts such! Modes were analysed utilising a Weibull cumulative distribution function will minimize your work and bring motor expertise and practical to. Breakdown in motor windings be in the form of heat, contamination, too much current, excessive and. Severely restricted filter drier smaller motors, while the motor and shaft currents all... S connection ( terminal ) box are a sure indication of this problem concerning the pectoralis Major goes. Failure analysis can be performed on electric motors serve as a ball is thrown in the motor and... Are 3 ways to screw up vibration analysis. ) motor windings driven device at the same speed the. A result of excessive starts or reversals as the motor, given what youve written in the to. Standard mounting dimension for an electric motor windings causing nuisance tripping or in furnaces... Investigating the cause of the windings as well as help you put together your motor purchase and repair policies help! Of the failure it may also occur as a foot and a foundation or. A sign of shorted to ground winding failure include high temperature, balance and distortion insulation failure typically...

1700 Koans Pdf, Articles O