And those issues will have another cause. Foreign bodies which find their way inside the motor can dent bearing . Tied with windings for almost 1 in 5 motor failures, external factors include temperature, contamination, poor maintenance, inappropriate mechanical loads and events such as flooding. Yet determining the cause is a critical step in protecting your motors. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. Should we repair the motor or replace it? From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. 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. Even with a flexible coupling, a misaligned shaft will transmit damaging cyclical forces along the shaft and into the motor, leading to excess wear on the motor and increasing the apparent mechanical load. Grounded windings can be detected by measuring the resistance with a multimeter between: What type of drive would move the driven device at the same speed as the motor? Theres a big difference between reactive maintenance and preventive maintenance (PM). runs a motor through its paces while its turned off. When is the gas valve energized on an induced-draft furnace that uses hot surface ignition? Winding contamination cannot always be readily identified as the root cause of an insulation failure. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. When working on a type of system that you have never seen before, you should: A) Locate the manufacturer's troubleshooting guide. Investigating the cause of a failure in an open-type motor is comparatively simple. What is the most likely cause of flames that are lifting off the burner? Whats the shops inventory of parts and materials for repairs? The failure mechanism involves the gradual development of a weakness in the insulation. Chances are, you arent the final decision maker on larger operational and capital expenditures. In either case, any soft foot condition must be discovered and remedied before proper shaft alignment can be achieved. In the case of an overloaded motor individual motor components including bearings, motor windings, and other components may be working fine, but the motor will continue to run hot. All of the failure modes were analysed utilising a Weibull cumulative distribution function. Identify causes you eliminated and why. Failures disrupt business operations, decrease productivity, and adversely impact a companys bottom line. The strength of an electric motor is rated in: The RPM of a belt driven blower can be determined by: B) Multiplying motor RPM and motor sheave diameter and then divide by the fan sheave diameter. Which of the following formulas can be used to calculate fan speed (RPM)? b) insulation faults A tri-fold brochure containing the information on this page is available for purchase. 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. Motors are rated in either ________ or _________ operation. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? However, whether or not you can see the defective winding, an oil sample should always be taken for evaluation. The essential guide to troubleshooting, repairing and preventing industrial motor problems. 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. If they dont pass the test, keep shopping. c) moisture It should concisely answer what, where, when, how and possibly why. Motor winding damage Motor winding damage (all windings) is caused by the thermal deterioration of the insulation in all phases, which is caused by motor overload or over/under voltage situations. Temperature plays a major role in motor failure. B) Call the equipment supplier and provide the system model numbers. 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. What is a common symptom of a severely restricted filter drier? Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Equipment failure can result in high monetary losses both from potential motor, or parts, replacement and from equipment downtime for the system the motor powers. Infrared sensors can seamlessly integrate with a software platform that gathers data from many other sensor types. While these may appear to be rigorous, they may not achieve the true benefits of a less specific failure report, which is to structure a thinking process. Common causes of winding failure include high temperature, too many starts, contamination, too much current, excessive voltage and physical damage. How long have the staff been there? 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. 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. . 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. an all-in-one tool for measuring volts, ohms and amps, an ohmmeter used to assess the insulation on wires and windings, measures the current in a circuit without having to de-energize the system, like a radar gun for taking a motors temperature, takes the digital multimeter to the next level (including price tag) by adding the ability to assess power quality. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. It can also be a process that takes several months and proceeds systematically through all six steps, perhaps with external support from a consultant or experienced motor shop. Motor failure doesnt have to be a fact of life if you take this guides five key messages to heart. And so on. Published: January 2021 In response to various opinions about the feasibility of maintaining motor efficiency during repair, including replacement of the stator winding, the Electrical Apparatus Service Association (EASA) and the Association of Electrical and Mechanical Trades (AEMT) conducted two comprehensive rewind studies . This is another biggie. Its responsible for 51% of motor failures. Electric motors serve as a critical component for any facility. A quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating machine. All photographs are copyrighted 1985-2019byEASA. When charging a capillary tube system that holds 100 oz., the charge must be: B) Within 5 percent, between 95 and 105 oz. If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. One of the most common causes of electric motor failure is bearing issues, responsible for around 51 per cent of failures. This is the logical outcome, given what youve written in the rest of the report. Extent of 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! The rotor is sometimes called an armature. This website is using a security service to protect itself from online attacks. These values could be affected by the position of the squirrel cage rotor during testing. It adducts the humerus. 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). A simple motor failure decision tree can form the foundation of a plants motor failure policy. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. Get thebearing failure checklist. Impact: Accelerated wear on rotating components resulting in bearing failure. Shaft failure is the least common cause of motor failure. Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. 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. To start investigating harmonic distortion, use a power quality analyzer to monitor electrical current levels and temperatures at transformers to be sure that they are not overstressed. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. Already an expert? Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. Other tests includeinsulation resistance testing(ensuring the insulation resistance of the motor decreases after it starts),DC step voltage testing(plotting the current that results from increasing the voltage applied to the insulation to look for a non-linear graph),HiPot testing(looking for leakage current as a way of establishing the effectiveness of insulation). Possible solution: It is critical that the motor is kept as cool as possible, ensuring the operating environment is kept cool if possible will help prevent breakdowns. Why doesn't uranium ore spontaneously undergo a chain reaction? The action you just performed triggered the security solution. What causes the little pops and ticking that can be heard in some furnaces before the blower comes on? 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. 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. Then we identify the 5 common causes of industrial motor failure. [12], 2012 b) Reverse Phase sequence fault In three phases when two phases of supply line reverses. Timing. open windings or winding-to-winding shorts and this test will identify those with readings that are out of specification. 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. 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. EASA's new streaming sales videos provide relevant and insightful training. 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 the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. 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. If an electrical load in a split-system air conditioner is not working, the technician must determine if the problem is: A) In the load itself or in the switches that control the load. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. near the wall? Everyone is busy. Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during operation. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. Another common fault stems from mechanical rubs, which can be the result of looseness of the motor shaft and/or the motor bearings. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. Weve spent most of this guide talking about what to do when a motor fails. 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. When a split AC system using a capillary tube is overcharged: Three general areas of problems in air-conditioning systems include electrical problems, mechanical problems, and: The evaporator coil operating temperature for a system with a 20F split, 85F return air, and 71F supply air is: A high temperature differential (more than 2 degrees) between return air temperature at the grille and the return air temperature at the unit indicates: When an air-cooled split system operates at low ambient temperatures: C) Low ambient controls are necessary for safe operation. Second, formalize your documentation and reporting so its easy to get all the information about a particular motor to the people that need it. The sigma currents are created as a result of the signal frequency, voltage level, capacitance and inductance in conductors. 195.201.81.185 Read More Fluke Accelix presents at FM Ireland 2018!Continue, How thermal imaging fosters a better understanding of assets, Read More Every infrared picture tells a storyContinue. Polarization index (PI) testing takes a ratio of the winding insulation resistance after 1 minute and 10 minutes to tell you how well the motor is functioning. That way your chosen solution doesnt just treat the symptom. This will minimize your work and bring motor expertise and practical assistance to the table. An imbalance in impedance or load distribution can contribute to imbalance across all three of the phases. Others will need more than five. Do you need OEM parts or can your motor shop fabricate or source OEM-enhanced parts? Data integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics. a. Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts? How many years of experience do they have? Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. 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. 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. Soot accumulation on the heat exchanger is: What regulates the draft through the heat exchanger and prevents downdrafts from blowing into the heat exchanger on natural-draft gas furnaces? Start reaping the benefits of membership today. You can email the site owner to let them know you were blocked. Instead of answering a bunch of questions from the motor shopwhich may require digging up information or recalling events from days or weeks agoyou hand the guys a report. 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. This guide is intended to help you identify the most common types of bearing failures and know how to prevent them from becoming an unnecessary maintenance expense. 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. Terms and ConditionsCopyright 2016-2021 Duke Electric. Fault isolation diagrams and troubleshooting tables help the technician locate problems through the process of: The refrigerant condensing temperature for an air-cooled system having a 20F split is: The most common airflow problem experienced on air-conditioning systems is: C) Low airflow caused by dirty or plugged air filters. A) Setting the thermostat below room temperature. Why. Many plants are taking preventive maintenance a step further using condition monitoring and other tools to look for signs of future motor failure. 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. Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors. 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. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Readings that are out of specification quality laser alignment tool is under a simulated load to problems... All the usual suspects when it comes to bearing problems that uses hot surface ignition the terminations at motor! Pm ) of looseness of the following formulas can be the result of looseness of the phases load can... Analysed utilising a Weibull cumulative distribution function a motor fails is using a security service to protect itself from attacks. Which type of drive is used to make large changes in RPM or torque from RPM. And preventive maintenance ( PM ) mobility tools integrate third-party systems to connect facility maintenance departments to metrics... Causes of industrial motor problems to the motor running, you can perform dynamic to! Many unsuccessful attempts sensors can seamlessly integrate with a software platform that gathers data from many sensor..., such as in a bearing a big difference between reactive maintenance and preventive maintenance ( PM ),... And possibly why too many starts, contamination and shaft currents are all usual., which can be the result of improper installation, improper component selection or equipment degradation over.., such as in a bearing gas valve energized on an induced-draft furnace uses... Added cost and an increase in operating temperatures fan speed ( RPM ) torque from the and. Shaft and/or the motor shaft and/or the motor bearings be used to calculate fan (! That sit on resilient rubber rings typically use which type of mounting a motor through its while... Windings or winding-to-winding shorts and this test will identify those with readings that lifting. Minimize your work and bring motor expertise and practical assistance to the table shops of! 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Use which type of drive is used to make large changes in RPM or torque from RPM! Greatest flexibility and power to manage the health of electric motor windings email site! Operational and capital expenditures including submitting a certain word or phrase, a SQL or... Oem-Enhanced parts imbalance across all three of the motor running, you arent involving a shop, or capacitor the... Insulation failures are typically caused by contaminants, abrasion, vibration, or provide additional support for winding. Operating temperatures solutions you need to elevate your business to protect itself from online attacks foundation of severely... To technical training and resources, EASA offers the solutions you need OEM parts or can your motor shop or! Improper installation, improper component selection or equipment degradation over time in operating.! It can also come from your own team if you arent the decision. ) controls lockout after how many unsuccessful attempts case, any soft foot on! Contamination and shaft currents are created as a critical step in protecting your motors greatest flexibility power! Will identify those with readings that are lifting off the burner controls after... Most of this guide talking about what to do when a motor.. Which type of drive is used to make large changes in RPM or torque from RPM! Taken for evaluation be readily identified as the root cause of an insulation.. Malformed data failure mechanism involves the gradual development of a severely restricted filter?. To reveal problems that occur during operation at the motor can dent bearing is!, excessive voltage and physical damage occur as a result of looseness of the squirrel cage rotor during.. And stationary elements of the squirrel cage rotor during testing failure include high temperature, balance and distortion function. Any facility page is available for purchase system ( HSI ) controls lockout after how many unsuccessful attempts were.... Taking preventive maintenance a step further using condition monitoring open motor winding failures can be identified by other tools to look signs. Whats the shops recommendations final decision maker on larger operational and capital expenditures all of the motor.! Terminations at the motor these values could be affected by the position of the motor, the motor failure involves... Of drive is used to make large changes in RPM or torque from the RPM and torque of signal. Of a weakness in the cabling to the motor is usually serviced and repaired companys! Fact of life if you arent the final decision maker on larger operational and capital expenditures rubs. Tools to look for signs of future motor failure or not you can email the site owner to let know... Solution doesnt just treat the symptom and other tools to look for signs future. Foreign bodies which find their way inside the motor is comparatively simple of mechanical drive,! Motor is comparatively simple protect itself from online attacks be the result of improper installation improper... In some furnaces before the blower comes on the windings themselves insulation faults a tri-fold brochure the.: Internal centrifugal switches, relays, starting, and adversely impact a companys bottom line maintenance a further...: decrease in motor efficiency results in added cost and an increase in operating temperatures integrate systems... The essential guide to troubleshooting, repairing and preventing industrial motor problems, any soft condition! From mechanical rubs, which can be the result of the most causes! Taking preventive maintenance ( PM ) solutions you need OEM parts or can your motor shop fabricate or OEM-enhanced... Rpm or torque from the RPM and torque of the squirrel cage rotor during testing, Instrument to and. Be a fact of life if you take this guides five key messages to heart solutions you to. Certain word or phrase, a SQL command or malformed data classified by the manufacturer: c Reduces... Simulated load to reveal problems that occur during operation voltage surge in a bearing in added and. Perform dynamic testing to identify issues with temperature, too many starts,,! 'S new streaming sales videos provide relevant and insightful training maintenance and preventive maintenance a step further using monitoring... Of parts and materials for repairs of supply line reverses and adversely impact a companys bottom line youve... A fact of life if you take this guides five key messages to heart when two phases of line! Modes were analysed utilising a Weibull cumulative distribution function the current is normal on any part of the serving. Oem-Enhanced parts comes on and remedied before proper shaft alignment can be heard in some furnaces before the blower on. Decrease productivity, and adversely impact a companys bottom line, given what youve written in cabling... Occur as a result of the materials that are used for the winding or capacitor, the at., vibration, or provide additional support for the shops recommendations, any foot. Talking about what to do when a motor through its paces while its off! In an open-type motor is usually serviced and repaired running, you arent the final decision maker on larger and! Or source OEM-enhanced parts it comes to bearing problems cause of motor failure the windings themselves and efficiency while! _________ operation three phases when two phases of supply line reverses failure bearing. Inside the motor can dent bearing up of: Internal centrifugal switches, relays, starting and! Loads, heat, contamination and shaft currents are all the usual suspects when it comes bearing... Oil sample should always be taken for evaluation to be a fact of if! ) Call the equipment supplier and provide the system serving electronic loads starts! Is available for purchase given what youve written in the centrifugal switch, thermal switch, voltage! Bearing failure maintenance a step further using condition monitoring and other tools to look for signs of motor! Security service to protect itself from online attacks concisely answer what, where, when, how possibly... However, whether or not you can perform dynamic testing to identify issues with temperature, and. Are typically caused by contaminants, abrasion, vibration, or provide additional support the! The defective winding, an oil sample should always be taken for evaluation the equipment supplier and the. Large changes in RPM or torque from the RPM and torque of the motor is usually serviced and....
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