We've put together a post onwinding failure, with awesome photos courtesy of EASA, if you're looking for examples. For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. As a technician's rule of thumb, fan speed should not be adjusted more than ________ percent above or below manufacturer's specifications. quent compressor failure can result within a few hours. Infrared imagers are the best technology for finding electrical hot spots in switchgear and motor controllers, for the screening process and mechanical assets. This is the first installment of a five-part series on common motor failures that will go on to cover motor windings, rotor bars, external conditions, and shaft couplings. 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). To learn more about testing tools and techniques, check out Motor Testing 101. 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 is the logical outcome, given what youve written in the rest of the report. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. 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. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. Yes, itll require some upfront work. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. 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. That way your chosen solution doesnt just treat the symptom. To get there, you have to understand the underlying causes of motor failures. You can email the site owner to let them know you were blocked. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. 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. Describe how energy changes as a ball is thrown in the air. Plant owners, operators, and managers can benefit from both integrated data and maintenance management with a single system. Get thebearing failure checklist. Things to look for during an inspection of your motor include: Signs of corrosion, dirt or debris on components, including fins, windings, contacts and relay, A burning smell that may indicate overheating, Signs of wear on the commutator and brush assembly, Anything unusual with the motor mount, stator, rotor and belts, Dirt buildup, inadequate lubrication and signs of wear on bearings, A bearing housing thats hot to the touch, Loose connections, including in the starter switch and fuses\. These transients, which vary in amplitude and frequency, can erode or cause insulation breakdown in motor windings. Include data and observations. Butdont screw it up. Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. 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. Explain why a sample of iron(III) sulfate is uncharged. An open winding falls into which general motor failure area? This can lead to bearing destruction within a few months of motor operation. Is it well suited for the application, or is it time to spec a new motor that can better accomplish what your process demands? When troubleshooting split air conditioning systems be sure to check voltage to: Which of these methods used to determine which component in a circuit is not working properly? If they can't, lubricate them. Check the bearings to make sure they can spin freely. EASA's new streaming sales videos provide relevant and insightful training. 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. 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. 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. Bearing failure is an expensive problem both in terms of motor repair and downtime, so helping to prevent this by measuring shaft voltage and bearing current is an important diagnostic step. Start by completely disconnecting the spindle motor from all power sources. The first signs of this problem will be noise and overheating as the bearings begin to lose their original shape and metal fragments mix with the grease and increase bearing friction. Other failures are caused by vibration, physical damage and situations that causes excessive heat. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. 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. Winding Failures. Chances are, you arent the final decision maker on larger operational and capital expenditures. 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. 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. Nearly half (48 percent) of all motor failures are due to electrical issues, according to a survey by the Electric Power Research Institute (EPRI). Start reaping the benefits of membership today. 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. Bearings are the culprit in more than half of motor failure cases. 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. When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. Impact: Arcing across bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure. b) the minimum tension required to keep the belt from slipping at its maximum torque Shaft failure is the least common cause of motor failure. They can test correct shaft alignment, imbalances, looseness, misalignment, and bearings. 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. These next-generation maintenance and reliability tools support the generation, collection, and consolidation of data from sensors, tools, and existing systems. The winding failures illustrated here are typical of what can happen is such circumstances. 1 in 10 failures are mysterious. Some plants have complex, detailed motor failure reporting processes, with hundreds of confusing failure codes. 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. Electric motors serve as a critical component for any facility. Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. Failures disrupt business operations, decrease productivity, and adversely impact a companys bottom line. If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. Using your existing staff, and scaling as necessary, you can implement without costly retrofitting and large IT infrastructure investments. Why is that, and which isotope is located near the axis? Imbalance is a condition of a rotating part where the center of mass does not lie on the axis of rotation. Reserve Your RoomSave your spot at EASA's official 2023 hotel - the Gaylord National Resport & Convention Center. 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. 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. Click to reveal That doesnt mean humans are off the hook, however. 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. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. To keep operations running smoothly, implementing preventive maintenance programs leads to a predictive and prescriptive maintenance future. For this reason, it makes sense to begin your troubleshooting by checking for motor overload. (If youve had small children in your life, youll also have flashbacks.) The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. The key is to dive deeper into understanding why the component failed. The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. 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. All photographs are copyrighted 1985-2019byEASA. That way, action can be taken before its too late. e) all of these, When measuring the leads of a multispeed shaded pole motor, there should be measurable resistance between all the leads. Everyone is busy. Use a multimeter or an ohmmeter to test the voltage of the electric motor. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. 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. Before diagnosing the problem as a failed compressor, always allow the motor protector time to reset, usually until the upper housing is within 5F of ambient temperature (this can vary by unit); 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. Variable frequency drives employ a pulse width modulation (PWM) technique to control the output voltage and frequency to a motor. (Here are7 ways to screw up vibration analysis.). How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. 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. Located between the stator and rotor, bearings are used to keep the rotor centred and shrink the air gap. 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. There could also be thermal deterioration in all phases of the stator winding typically due to load demands exceeding the rating of the motor or by very high currents in the stator winding due to a locked rotor. And so on. If there is no resistance or the resistance is uneven, the motor is likely faulty. Extent of failure. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. 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. The benefits of detecting, identifying, and evaluating electric motor abnormalities are decreased motor failures and less unexpected downtime. Adjacent loads turning on or off, power factor correction capacitor banks or even distant weather can generate transient voltages on distribution systems. Cost. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Thermal Stress Failures. 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. It can also detect the presence of dirt or moisture. 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. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. What is the most likely cause of flames that are lifting off the burner? 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. This is another biggie. 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. Open windings are also caused by shorted turns, phase-to-phase shorts, ground-to-frame shorts, faulty internal coil-to-coil connections, severe overloads, and physically damaged coils. Transient voltages can come from several sources either inside or outside of the plant. Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures. By completely disconnecting the spindle motor from all power sources more about testing tools and techniques, check motor. 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