What is the first step in the operational sequence? 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. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. If they dont pass the test, keep shopping. From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! It raises the clavicle. Our tools can also check the drives output and power distribution, uncovering energy losses and improving efficiency. It may also occur as a result of excessive starts or reversals. Motors are rated in either ________ or ________ operation. If there is no resistance or the resistance is uneven, the motor is likely faulty. Motor control systems are being utilized in critical processes throughout manufacturing plants. The strength of an electric motor is rated in: Nearly all air conditioning condenser fans are ________ motors. Angular soft footangular soft foot occurs when one of the mounting feet is not parallel or normal to the mounting surface. In addition, misalignment may feed vibration into both the load and the motor drive shaft. This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. 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. The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. Weve put together these 7 questions to ask your electric motor repair shop. Already an expert? The correct tension for any belt drive application is: Symptoms of an inefficient compressor include: B) High suction pressure, low discharge pressure, and low amp draw. That way your chosen solution doesnt just treat the symptom. Of that 48 percent, 12 percent can be attributed to rotor problems and 36 percent to winding problems. 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. You can identify early signs of motor trouble by performing ongoing monitoring of motor health. 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. To keep operations running smoothly, implementing preventive maintenance programs leads to a predictive and prescriptive maintenance future. Does the shop have experience with your motor? 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. More than one response required. A single-phased winding failure is the result of an open in one phase of the power supply to the motor. Data integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics. Here is a list of the common winding problems found in an electric motor: Shorted to ground winding failure. Its one thing to identify the component thats failed and another thing to isolate the cause of that component 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. Check each wire, including T1, T2, T3 and the ground wire. Lets take bearing failure, for example. This is another biggie. 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. 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". 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. . Second, formalize your documentation and reporting so its easy to get all the information about a particular motor to the people that need it. Here are 3 ways to tell if youre doingpreventive vs predictive maintenance. c) moisture Sounds simple. These losses dissipate in the form of heat, which, over time, will deteriorate the insulation capability of the windings. 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. Winding Shorted Turn-to-Turn When a motor goes down, someone has to be told. 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. These transients, which vary in amplitude and frequency, can erode or cause insulation breakdown in motor windings. That way, action can be taken before its too late. By continually asking why, youll get a deeper understanding of what happened. Yet determining the cause is a critical step in protecting your motors. Why is that, and which isotope is located near the axis? 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); It may also occur as a result of excessive starts or reversals. How long have the staff been there? Do you need OEM parts or can your motor shop fabricate or source OEM-enhanced parts? Chances are, you arent the final decision maker on larger operational and capital expenditures. PM has been shown to reduce downtime by as much as 50%. Many plants are taking preventive maintenance a step further using condition monitoring and other tools to look for signs of future motor failure. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. In a motor drive circuit, the peak of the reflection could be as high as the DC bus voltage level. 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. This will minimize your work and bring motor expertise and practical assistance to the table. 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. If the motor is less than 1/8 HP, it is almost always replaced. 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. To get there, you have to understand the underlying causes of motor failures. Winding shorted turn-to-turn The resistance of ________ can accurately be predicted using Ohm's law. Stator winding failures are generally attributed to groundwall or turn insulation failures. (Note: almost all misalignment is compound misalignment, but practitioners talk about misalignment as the two separate types because it is easier to correct a misalignment by addressing the angular and parallel components separately.). 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. Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. C) Expansion of the heat exchanger as it heats up. 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. Uneven mass in motor windings and other wear-related factors. 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. A brush assembly is often used to shift the current. Switching power circuit, capacitor discharges, or solid-state power devices can also cause this type of motor winding damage CUSTOM BRANDED PRODUCTSDOWNLOADS YOU HAVE PURCHASEDVIEW YOUR PURCHASED TRAININGVIEW CONVENTION RECORDINGS. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. 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". If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. An imbalance in impedance or load distribution can contribute to imbalance across all three of the phases. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. 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. You can email the site owner to let them know you were blocked. Then we identify the 5 common causes of industrial motor failure. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. D) Suction pressure goes down and superheat increases. Will the shop do the work themselves, or will they outsource it? Motor overload occurs when a motor is under excessive load. 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. Reproduction of these photographs by print or electronic means is prohibited. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. If its an older motor, can you find a new motor that will fit in the old spot, given that new motors tend to be smaller than an equivalent motor made 25-plus years ago? Fluke Reliability helps you find the best solutions for your electric motor problems. That way you can save your bearing next time, instead of simply having it fail again. Pipe strain refers to the condition in which new stresses, strains, and forces, acting on the rest of the equipment and infrastructure transfer backward onto the motor and drive to induce a misalignment condition. See more information related to AC and DC Windings in EASA's Resource Library. 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? Which failure could cause nothing to happen when the thermostat is set to heat? Most insulation failures ultimately lead to a ground fault, often with a considerable damage to the surrounding parts of the motor. 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. 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. The key is to dive deeper into understanding why the component failed. 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\. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. The ________ is used to identify all the controls in series with the load. PM has been shown to reduce downtime by as much as 50%. All photographs are copyrighted 1985-2019byEASA. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance 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. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. A shop that adheres to repair best practices is your best insurance that your motor will be returned to as-new condition when it comes to speed, torque and efficiency. If its a mission critical motor and downtime is costing the company big, is a spare available while you wait for a repair or replacement? Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surg What causes electric motors to fail? Its responsible for 51% of motor failures. Instrument to measure and diagnose: Fluke 810 Vibration Tester. Charred connections in the motor's connection (terminal) box are a sure indication of this problem. Everyone is busy. 4. In either case, any soft foot condition must be discovered and remedied before proper shaft alignment can be achieved. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. Monitoring has two components: inspection and testing. 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. But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. Contamination. De-energized testing runs a motor through its paces while its turned off. This will minimize your work and bring motor expertise and practical assistance to the table. 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. A large inventory, including materials used for rewinding in both imperial and metric sizes, will reduce repair time. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. Heres how a motor failure report can help with motor management. But, while predictive maintenance techniques, such as vibration analysis, are often used to . 195.201.81.185 Larger blower wheels are typically operated by ___________ motors. Start by completely disconnecting the spindle motor from all power sources. Winding insulation breakdown and bearing wear are the two most common causes of motor failure, but those conditions arise for many different reasons. D) The large temperature drop indicates the airflow is less than required. Infrared sensors can seamlessly integrate with a software platform that gathers data from many other sensor types. 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. Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors An open internal motor overload is distinguished by: a) measurable resistance between run and start b) infinite resistance between start and common c) infinite resistance between run and common d) all of these d) all of these However, its important to move toward predictive maintenance programs. Smith, Michael Abbott. If not, you might not get the most qualified team or best price. 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? Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. This weakness is . 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. This is the logical outcome, given what youve written in the rest of the report. Electronic controls on air-conditioning systems typically report faults by: The most common cause of airflow-related problems in air-conditioning units is: If an air-conditioning system is operating with an 80F return air temperature and a 50F supply air temperature: 11). Potential relays measure the back ______ developed across the _______ winding to operate the relay. 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. Skip to the next section on. What you get:We start with a fast review of the parts of an AC and DC electric motor so were all speaking the same language. For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. Contact us to speak with a specialist. A) 240 volts. But the down-the-road benefits will pay off big. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. Sales professionals need to keep their skills sharp in order to discover new leads, nurture promising prospects and close more deals. Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts? 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. When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. A root cause failure analysis can be relatively quick and informal. Skip to the next section on common causes of electric motor failure. 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. When replacing fuses be sure to match which of these ratings? 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. Motors are rated in either ________ or _________ operation. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. But wouldnt it be better to avoid failure in the first place? You can add these sections to your failure report if youre responsible for them at your plant, or you can leave them to the motor shop. 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