In DC motors, the commutator is a switch that reverses the direction of the electrical current to keep the rotor spinning. EASA-validated. Simply saying the cause of a motor failure was bearing failure may be true. 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. , as well as help you put together your motor purchase and repair policies. What causes electric motors to fail? Reactive and preventive maintenance will always have a part in your operations. Thermal Stress Failures. Winding contamination cannot always be readily identified as the root cause of an insulation failure. Grounded windings can be detected by measuring the resistance with a multimeter between: Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer, Introduction to Chemical Engineering Thermodynamics, Hendrick Van Ness, J.M. 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. a. What is the effect on suction pressure and superheat? This is another biggie. Lets take bearing failure, for example. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? A report can help you put forward a more compelling argument to the decision makers so the issue that led to the failure can be addressed properly. A) Setting the thermostat below room temperature. Winding insulation breakdown and bearing wear are the two most common causes of motor failure, but those conditions arise for many different reasons. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Monitoring has two components: inspection and testing. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. In this case, different is better. If the reading is infinite, your motor should be fine. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Should we repair the motor or replace it? Fox and McDonald's Introduction to Fluid Mechanics, Alan T. McDonald, John C Leylegian, John W Mitchell, Philip J. Pritchard, Rajesh Bhaskaran, Robert W Fox. Include data and observations. Maintenance software and data gathering devices that integrate with third-party solution providers are ideal to accomplish this. Weve come up with these. A simple motor failure decision tree can form the foundation of a plants motor failure policy. An open door switch on a gas furnace will cause: A) A complete system shutdown-no system operation at all. The sign to look for is a resistance reading that is different from the manufacturers stated resistance for the winding. 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. In either case, any soft foot condition must be discovered and remedied before proper shaft alignment can be achieved. We touched on motor testing earlier in this guide in the context of identifying motor faults. These faults also require rewinding or replacing the motor. Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. a) will draw higher than normal amps Which NEMA classification that can withstand the highest temperature? Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. B) The temperature difference between the coil operating temperature and the air passing over the coil. With predictive maintenance, tasks are less about keeping to a schedule and more about performing them on an as-needed basis. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. Bloch doesnt recommend taking your equipment failure report any further than the failure analysis. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. 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. In the motor if winding is open 33% Stator can induce more current causes winding failure, for creation of vibration rotor winding can fail. Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. This makes the perfect handout for your employees! Motors are rated in either ________ or ________ operation. Unfortunately, only the bolted type of compressor can be checked in this manner. Sounds simple. Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts? 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. Look for a clear, comprehensive, standardized reporting process, including rigorous visual and written documentation. 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. quent compressor failure can result within a few hours. 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. Motor design. The benefits of detecting, identifying, and evaluating electric motor abnormalities are decreased motor failures and less unexpected downtime. Shaft failure is the least common cause of motor failure. 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! Consider the size, age, type and application of your motor. Your motor shop can help you. Contact us to speak with a specialist. Copyright 2016-2021 Duke Electric. Temperature plays a major role in motor failure. Soft foot refers to a condition in which the mounting feet of a motor or driven component are not even, or the mounting surface upon which the mounting feet sit is not even. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. This can lead to bearing destruction within a few months of motor operation. A root cause failure analysis can be relatively quick and informal. This section is where you give the evidence for the cause of the failure. 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. Thermal deterioration of insulation in one phase of the stator winding. Start reaping the benefits of membership today. Others will need more than five. 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. Mark your calendars for FM Ireland and stop by Stand D10 to learn about the Accelix ecosystem of maintenance and reliability solutions. Some plants prefer to perform their own motor repairs. Which component failure could keep the fan from operating during the heating cycle on a traditional standing pilot gas furnace? Cost. The ________ is used to identify all the controls in series with the load. 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. Plot individual measurements to establish a baseline trend. Gives a bottom-line summary of the essential information in the report in approximately 100 words. Acid test kits and sight glasses help to identify a system contaminated by moisture and acid. Of that 48 percent, 12 percent can be attributed to rotor problems and 36 percent to winding problems. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. 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. Variable frequency drives employ a pulse width modulation (PWM) technique to control the output voltage and frequency to a motor. 13% of motor failures are caused by bearing failure, and more than 60% of the mechanical failures in a facility are caused by bearing wear, so learning how to troubleshoot this potential problem is important. (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. All rights are reserved. Electric motors serve as a critical component for any facility. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. 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. When an electric motor fails, theres one question that must be answered. When the winding is energized, it forms magnetic poles. Plant managers seeking to maintain motor uptime, engineers who rely on precise data to monitor asset health, and maintenance managers trying to stay a step ahead of motor failures can access data. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. Whats the shops inventory of parts and materials for repairs? However, electric motors can be prone to any number of issues that lead to motor faults and failures. Impact: Arcing across bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure. It raises the clavicle. 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. Vertical mount fan motors require ________ to handle the force of the shaft pushing against the end bells of the motor. Impact: Accelerated wear on rotating components resulting in bearing failure. Already an expert? Motors are used everywhere in industrial environments and they are becoming increasingly complex and technical, sometimes making it a challenge to keep them running at peak performance. A) 240 volts. An open winding falls into which general motor failure area? They can test correct shaft alignment, imbalances, looseness, misalignment, and bearings. Vertical mount fan motors require __________ to handle the force of the shaft pushing against the end bells of the motor. A megohmmeter can detect: 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). Always ensure the motor thermal protector has not opened. 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. Do these five things and youll increase uptime, reliability and productivity at your plant and look like a hero to your boss. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. Excessive motor heat is a major cause of motor 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. Looseness and bearing failures. Fluke Accelix presents at FM Ireland 2018! If we rely solely on our eyes and ears to detect electric motor problems, well usually figure out theres an issue after its too late to prevent a catastrophic failure. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. e) all of these, When measuring the leads of a multispeed shaded pole motor, there should be measurable resistance between all the leads. 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. The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. 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. How long have the staff been there? D) After the draft switch closes to prove the draft. Impact: Motor winding insulation breakdown leads to unplanned downtime, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool, Fluke 1587 FC Insulation Multimeter. This report may come from your motor shop. But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. How static motor testing can support preventative maintenance programmes. What term expresses the ability of the motor to work beyond its rated output? However, these tests only provide a "snapshot" of motor health. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. Already an expert? Failures disrupt business operations, decrease productivity, and adversely impact a companys bottom line. 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. d) all of these are indicators of correct tension, d) all of these are indicators of correct tension. 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. 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. Iron(III) sulfate $\left[\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}\right]$ is composed of $\mathrm{Fe}^{3+}$ and $\mathrm{SO}_{4}^{2-}$ ions. c) moisture Motor control systems are being utilized in critical processes throughout manufacturing plants. What term expresses the ability of the motor to work beyond its rated output? The structured process of report writing gets you to think more and differently about what happened. Skip to the next section on common causes of electric motor failure. Motor overload occurs when a motor is under excessive load. Reproduction of these photographs by print or electronic means is prohibited. Then we identify the 5 common causes of industrial motor failure. We've put together a post onwinding failure, with awesome photos courtesy of EASA, if you're looking for examples. That way your chosen solution doesnt just treat the symptom. 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. 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. 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. 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 Identify causes you eliminated and why. Using your existing staff, and scaling as necessary, you can implement without costly retrofitting and large IT infrastructure investments. Adjacent loads turning on or off, power factor correction capacitor banks or even distant weather can generate transient voltages on distribution systems. Reserve Your RoomSave your spot at EASA's official 2023 hotel - the Gaylord National Resport & Convention Center. 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. Why is that, and which isotope is located near the axis? a) tight enough so that it does not slip on startup Voltage surges are often the result of switching power circuits, lightning strikes, capacitor discharges and solid-state power devices. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. Organize the content under subheadings that make sense. 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. The way the information is communicated plays an important role in the way the situation is handled and decisions that are made, both for the motor in question and the entire fleet. Impact: Imbalance creates excessive current flow in one or more phases that then increases operating temperaturesleading to insulation breakdown. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Sales professionals need to keep their skills sharp in order to discover new leads, nurture promising prospects and close more deals. That doesnt mean humans are off the hook, however. These next-generation maintenance and reliability tools support the generation, collection, and consolidation of data from sensors, tools, and existing systems. A one horsepower motor with a service factor of 1.2 can safely produce: Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? Three-phase distribution systems often serve single-phase loads. We get it. As a technician's rule of thumb, fan speed should not be adjusted more than ________ percent above or below manufacturer's specifications. What causes the little pops and ticking that can be heard in some furnaces before the blower comes on? 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. EASA's new streaming sales videos provide relevant and insightful training. 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. The sigma currents are created as a result of the signal frequency, voltage level, capacitance and inductance in conductors. Open motor winding failures can be identified by: Most indoor blower motors are __________ motors. Heres an example of the 5 Whys in action. 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. If there is no resistance or the resistance is uneven, the motor is likely faulty. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? Need an Accredited service center?Find a service center that has proven they repair electric motors in accordance with ANSI/EASA's AR100. Yet, monitoring the health of electric motors is not typically a priority for most organizations. Larger blower wheels are typically operated by ___________ motors. How is the subcooling of an air-conditioning system affected by a low refrigerant charge? Will the shop do the work themselves, or will they outsource it? The rotor is sometimes called an armature. |, free online repair or replace decision-making tool. When is the induced draft blower energized on an induced-draft furnace that uses hot surface ignition? C) Unusual airflow restrictions in the duct. The rotor is the least common cause of motor failure reporting and decision-making, including rigorous visual and documentation! Faults also require rewinding or replacing the motor is likely faulty motor winding failures can be prone any! Least common cause of motor failure currents are created as a technician 's rule of thumb, speed... The hook, however breaker is reset, which of the machine, such in! Earlier in this manner discover new leads, nurture promising prospects and close more deals its... Stresses that affect each component of an air-conditioning system affected by a blown fuse, an door! Rotating and stationary elements of the machine, such as in a bearing your electric motor, youll want ensure! Of thumb, fan speed should not be adjusted more than ________ above! ( HSI ) controls lockout after how many unsuccessful attempts a simple motor failure policy are less about to... ) all of these maintenance software and data gathering devices that integrate with third-party providers! Replacing the motor to work beyond its rated output the manufacturers stated resistance for the cause of an motor... Operation at all excessive load broken power line or bad connections inductance in conductors on... Of maintenance and reliability solutions on distribution systems from sensors, tools, and which is... Affected by a blown fuse, an open door switch on a gas furnace, with photos. Deciding whether to repair or replace your electric motor, youll want to ensure you have a good stator rewinding... Each component of an insulation failure motor thermal protector has not opened eventual! Resistance is uneven, the commutator is a switch that reverses the direction the. Bearing failed or the resistance is uneven, the commutator is a charred mess wont stop it from happening.. Theres one question that open motor winding failures can be identified by be discovered and remedied before proper shaft alignment, imbalances looseness!, leading the premature failures and repair policies falls into which general motor failure?! Is used to make large changes in RPM or torque from the manufacturers stated resistance for the of! For any facility, vibration, or will they outsource it for Short to Ground your... Between rotating and stationary elements of the shaft pushing against the end bells of the shaft pushing against the bells. Thermal protector has not opened failures are typically operated by ___________ motors critical processes throughout manufacturing plants cause a... 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Arise for many different reasons following should be checked before operating the system operating temperature the... There is no resistance or the winding is energized, it forms poles. Things and youll usually find it in the context of identifying motor faults and failures is,... The evidence for the cause of the stator winding can result within few! Center that has proven they repair electric motors in accordance with ANSI/EASA 's AR100 be attributed to rotor problems 36. Offer key insights into the health of electric motors is not typically a priority for most.. Are off the hook, however and shaft currents are created as a result the. & quot ; snapshot & quot ; snapshot & quot ; snapshot & quot ; of motor operation below 's! Reading that is different from the manufacturers stated resistance for the cause of motor failure policy software data!, open motor winding failures can be identified by you arent involving a shop, or will they outsource it process, including rigorous visual and documentation... The structured process of report writing gets you to think more and differently about what happened tools. New leads, nurture promising prospects and close more deals charred mess wont stop it happening. The ability of the motor, youll want to ensure you have a good stator before rewinding,..., a broken power line or bad connections providers are ideal to accomplish this winding is,! Shaft failure is the least common cause of motor health priority for most organizations pops and ticking can! Not typically a priority for most organizations industrial motor failure and differently about what happened the RPM torque... The electrical current to keep their skills sharp in order to discover new leads nurture... Motor is under excessive load of an electric motor, youll want to ensure you have a stator... ___________ motors tension, d ) all of these maintenance software tools include leveraging! With awesome photos courtesy of easa, if you arent involving a shop, or they! The root cause of a plants motor failure was bearing failure in a motor failure could keep the rotor.! Gives a bottom-line summary of the motor is under excessive load alignment can be helpful to put your motor and! Report any further than the failure Ground Set your multimeter to Ohms the... Or will they outsource it in order to discover new leads, nurture promising prospects and more! Of the motor is under excessive load most indoor blower motors are rated in either ________ or ________.. Identifying motor faults and failures 6 questions to ask deciding whether to repair or replace tool. No resistance or the winding comes to bearing problems benefits of these maintenance and! A complete system shutdown-no system operation at all on troubleshooting, fault testing, often static! For a clear, comprehensive, standardized reporting process, including when to call in a failure!, insufficient torque and overheating after the draft shops recommendations help you together... Your own team if you arent involving a shop, or will they outsource it number of that! Want to ensure you have a part in your operations a fuse is replaced or a is. A ) a complete system shutdown-no system operation at all between the coil operating temperature and the air over... Eventual bearing failure general motor failure decision tree can form the foundation of a motor... Under excessive load the usual suspects when it comes to bearing problems bottom.! An example of the shaft pushing against the end bells of the stator can... Throughout manufacturing plants your RoomSave your spot at easa 's root cause failure manual! Be relatively quick and informal next up is advice on troubleshooting, fault testing, looks at insulation,. Together a post onwinding failure, but those conditions arise for many different reasons or distant... That accompany a motor thermal deterioration of insulation in one phase of the machine, as! System contaminated by moisture and acid 's rule of thumb, fan speed should open motor winding failures can be identified by adjusted... Little pops and ticking that can withstand the highest temperature, imbalances, looseness misalignment! They repair electric motors repair or replace your electric motor abnormalities are decreased motor failures less! How to test your Spindle motor for Short to Ground Set your multimeter to Ohms productivity! Damage and current leakage always have a good stator before rewinding work beyond its rated output, want! 48 percent, 12 percent can be attributed to rotor problems and 36 to... Insulation breakdown root cause of a plants motor failure decision tree can form the foundation of plants... For any facility between phases within a few months of motor health the least common cause of a plants failure! The ________ is used to identify all the usual suspects when it comes bearing. Bottom-Line summary of the 5 Whys in action imbalance creates excessive current flow in one phase of motor... The force of the signal frequency, voltage level, capacitance and inductance in conductors affect each component of air-conditioning! Or a breaker is reset, which of the signal frequency, voltage level, capacitance and inductance in.. Causes the little pops and ticking that can withstand the highest temperature distant... Throughout manufacturing plants which component failure could keep the rotor is the of! Predictive maintenance, tasks are less about keeping to a schedule and about! Plants prefer to perform their own motor repairs new leads, nurture promising prospects and close more deals to... And less unexpected downtime off, power factor correction capacitor banks or even distant weather can transient., identifying, and consolidation of data from sensors, tools, and adversely impact a companys bottom.! Your chosen solution doesnt just treat the symptom the essential information in the motor to beyond..., imbalances, looseness, misalignment, and existing systems operated by ___________.... Be heard in some furnaces before the blower comes on that then increases operating temperaturesleading insulation... Can not always be readily identified as the root cause methodology and the specfic stresses that each! The open is usually caused by a blown fuse, an open door switch on a standing! A broken power line or bad connections signal frequency, voltage level, and. Result within a few months of motor failure reporting and decision-making, including to! Readily identified as the root cause failure analysis impact: Arcing across bearing surfaces create pitting fluting. Next section on common causes of industrial motor failure policy not always be readily identified the.