But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. 4. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. The stator is the stationary part of the motor. However, electric motors can be prone to any number of issues that lead to motor faults and failures. Various factors, such as overheating, physical damage . Its responsible for 51% of motor failures. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? D) Suction pressure goes down and superheat increases. The action you just performed triggered the security solution. When you suspect an issue with your electric motor winding, there are three categories of measurements to help identify the likely source of failureselectrical, mechanical, and thermal. The ________ is used to identify all the controls in series with the load. Third, make your motor repair and replace decisions using an industry-accepted decision tree oronline decision toolto standardize and speed up your process. Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. You can identify dead shorts, loose connections and open circuits in coiled windings using a digital multimeter. 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. Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during operation. These faults also require rewinding or replacing the motor. Start by completely disconnecting the spindle motor from all power sources. Always ensure the motor thermal protector has not opened. Severe thermal deterioration of the insulation in all phases of the motor normally is caused by very high currents in the stator winding due to a locked rotor condition. Which of the following formulas can be used to calculate fan speed (RPM)? This section is where you give the evidence for the cause of the failure. Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. Document operating condition, machine specifications and performance tolerance ranges. 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 . On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. It can also detect the presence of dirt or moisture. 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. Electrical unbalance usually indicates an electrical failure such as an open stator or rotor winding, an open bar or ring in squirrel cage motors or shorted field coils in synchronous. Shaft failure is the least common cause of motor failure. In other words, the return current from the drive would be equal to the current to the drive. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. The best way to diagnose an ECM motor is to: D) Turn off power to the unit, remove the control harness, and connect a test controller, Larger blower wheels are typically operated by ________ motors. Are the techs CSA-certified? Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. CUSTOM BRANDED PRODUCTSDOWNLOADS YOU HAVE PURCHASEDVIEW YOUR PURCHASED TRAININGVIEW CONVENTION RECORDINGS. 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. Your motor shop can help you. 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. We've put together a post onwinding failure, with awesome photos courtesy of EASA, if you're looking for examples. This will minimize your work and bring motor expertise and practical assistance to the table. The structured process of report writing gets you to think more and differently about what happened. Vertical mount fan motors require ________ to handle the force of the shaft pushing against the end bells of the motor. One of the most common causes of electric motor failure is bearing issues, responsible for around 51 per cent of failures. The root cause methodology starts with the failed component, then follows a step-by-step process to understand the stresses that caused the component to fail. Your IP: The motor and insulation tester assure safe operation, prolongs the life of electrical systems and motors. 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. 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. Others will need more than five. 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. 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. Keep all of your organizations assets up and running without downtime. Impact: Arcing across bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure. Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. Simply stated, harmonics are any unwanted additional source of high frequency AC voltages or currents supplying energy to the motor windings. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Located between the stator and rotor, bearings are used to keep the rotor centred and shrink the air gap. A common cause of an open winding is undersized lead lugs. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. The strength of an electric motor is rated in: Nearly all air conditioning condenser fans are ________ motors. If there is no resistance or the resistance is uneven, the motor is likely faulty. Lets take bearing failure, for example. We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. This article demonstrates how to detect the 13 most common causes of winding insulation and bearing failure in advance. When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. How unique is it? 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. c) 1/64th inch deflection per 1 inch span between drive shaft and driven shaft open windings or winding-to-winding shorts and this test will identify those with readings that are out of specification. Data integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics. 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. C) Expansion of the heat exchanger as it heats up. If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. This will help you identify patterns with a particular asset and make warranties easy to manage. quent compressor failure can result within a few hours. Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. Choose the more stable alkene in each of the following pairs. Thermal Stress Failures. Impact: Accelerated wear on rotating components resulting in bearing failure. 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 . 1 in 10 failures are mysterious. near the wall? A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. A) 240 volts. Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? Looseness and bearing failures. 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. 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. It is critical to determine the best course of action should a failure occur. Cost. It may also occur as a result of excessive starts or reversals. The voltage will be ________ immediately after the control that is opening the circuit. 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. Which component failure could keep the fan from operating during the heating cycle on a traditional standing pilot gas furnace? To learn more about testing tools and techniques, check out Motor Testing 101. We get it. Because 30% of motor failures are caused by overloading, it is important to understand how to measure for and identify motor overloading. [12], 2012 b) Reverse Phase sequence fault In three phases when two phases of supply line reverses. Is it well suited for the application, or is it time to spec a new motor that can better accomplish what your process demands? Motor design. Create an archive reference of measurements to facilitate trend analysis and identify change of state conditions. To keep operations running smoothly, implementing preventive maintenance programs leads to a predictive and prescriptive maintenance future. 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. A quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating machine. Should we repair the motor or replace it? Motor failure doesnt have to be a fact of life if you take this guides five key messages to heart. The machines provide the data. Does the shop have a significant amount of experience with your motor? 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. 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. It should concisely answer what, where, when, how and possibly why. Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. The rotor is sometimes called an armature. 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 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. Unequal voltages usually are caused by unbalanced loads on the power source, a poor connection at the motor terminal, or a high resistance contact (weak spring). Reserve an intensive root cause analysis for repeated, high-cost motor failures. c. It abducts the arm. Stator winding failures are generally attributed to groundwall or turn insulation failures. EASA's new streaming sales videos provide relevant and insightful training. Your motor shop can help you identify critical assets,establish an online motor database, and store and maintain your spares, as well as help you put together your motor purchase and repair policies. Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. Foreign bodies which find their way inside the motor can dent bearing . Motors are rated in either ________ or ________ operation. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. 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. Motor control systems are being utilized in critical processes throughout manufacturing plants. Problems that occur during operation take this guides five key messages to heart, connections! Protective earth current flow, Instrument to measure and diagnose: Fluke 830 Laser shaft Alignment Tool machine specifications performance. Three phases when two phases of supply line reverses Nearly all air conditioning condenser fans are ________ motors,!, or capacitor, the motor thermal protector has not opened with awesome photos of! Were all speaking the same language out motor testing 101 loose connections open... Dead shorts, loose connections and open circuits in coiled windings using a digital.... 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