open motor winding failures can be identified by

Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. 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. Always ensure the motor thermal protector has not opened. Acid test kits and sight glasses help to identify a system contaminated by moisture and acid. Starts (too many, not enough of a break between them or extended start times) are the culprit in some rotor failures. A simple motor failure decision tree can form the foundation of a plants motor failure policy. When replacing fuses be sure to match which of these ratings? However, electric motors can be prone to any number of issues that lead to motor faults and failures. A) 240 volts. VIEW THE LISTLEARN MORE ABOUT THE PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE OF EVENTS. b) the minimum tension required to keep the belt from slipping at its maximum torque Document operating condition, machine specifications and performance tolerance ranges. Switching power circuit, capacitor discharges, or solid-state power devices can also cause this type of motor winding damage That doesnt mean humans are off the hook, however. Motors are rated in either ________ or ________ operation. But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? Why. Instead, he recommends including these four parts, which can be further broken into subheadings according to the situation. D) Suction pressure goes down and superheat increases. The action you just performed triggered the security solution. And so on. It treats the underlying condition that created the situation in the first place. EASA's new streaming sales videos provide relevant and insightful training. You remove the end bell, and the entire winding can be examined. 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. Once acid is identified in 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. 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. Copyright 2016-2021 Duke Electric. When ohming components on the system, it is important to: How is the subcooling of an air-conditioning system affected by a restriction in the liquid line? 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. The voltage will be ________ immediately after the control that is opening the circuit. 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. Shaft failure is the least common cause of motor failure. Know the breakpoints at which youre willing to repair vs. replace. What is a common symptom of a severely restricted filter drier? Uneven mass in motor windings and other wear-related factors. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. Impact: Arcing across bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure. Reserve an intensive root cause analysis for repeated, high-cost motor failures. Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. 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. They also enhance remote monitoring capabilities through connected devices including desktop, tablet, or smartphone. 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. These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. Impact: Imbalance creates excessive current flow in one or more phases that then increases operating temperaturesleading to insulation breakdown. You can identify early signs of motor trouble by performing ongoing monitoring of motor health. Whats the lead time on a new motor? B) The temperature difference between the coil operating temperature and the air passing over the coil. Thankfully, computerized equipment and tools can detect issues at levels and in places that human senses arent able to. What is their internal quality management system and how do they make sure theyre following it? Weve put together a separatepreventive maintenance guideto help you out. A tri-fold brochure containing the information on this page is available for purchase. Which component failure could keep the fan from operating during the heating cycle on a traditional standing pilot gas furnace? 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? These circulating currents can find their way through protective earth systems causing nuisance tripping or in some cases excess heat in windings. 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. 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. 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. Using your existing staff, and scaling as necessary, you can implement without costly retrofitting and large IT infrastructure investments. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. To diagnose a problem, there are three steps within each category to help quickly and efficiently manage the repair workflow: Before returning the machine to service, perform a quick screening to ensure the repairs are completed. But wouldnt it be better to avoid failure in the first place? Plot individual measurements to establish a baseline trend. 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? Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? This is another biggie. Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. Motor windings account for about 32% of all AC electric motor repairs. 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. However, if the motor is more than 10 years old and less than 1 HP, the motor is usually replaced. (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.). Ball bearings are used in smaller motors, while the big boys will have roller bearings. Whats the shops inventory of parts and materials for repairs? takes place while the equipment is under a simulated load to reveal problems that occur during operation. It adducts the humerus. A) motors, When hopscotch troubleshooting, follow the schematic and move the meter lead on the control side of the circuit from one control to the next, checking the voltage in and out of the control. What is the effect on suction pressure and superheat? Should we repair the motor or replace it? 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. An imbalance in impedance or load distribution can contribute to imbalance across all three of the phases. a) tight enough so that it does not slip on startup d) all of these are indicators of correct tension, d) all of these are indicators of correct tension. Third, make your motor repair and replace decisions using an industry-accepted decision tree oronline decision toolto standardize and speed up your process. The failure mechanism involves the gradual development of a weakness in the insulation. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. Start by completely disconnecting the spindle motor from all power sources. A) Adding refrigerant increases the system subcooling. Charred connections in the motor's connection (terminal) box are a sure indication of this problem. An open winding falls into which general motor failure area? When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. Opens are indicated by infinite resistance or impedance reading. Its important to remember that the causes of motor and drive issues are not confined to a single domain of expertiseboth mechanical and electrical issues can lead to motor failureand being armed with the right knowledge can mean the difference between costly downtime and improved asset uptime. Yes, itll require some upfront work. 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. Which NEMA classification can withstand the highest temperature? This section is where you give the evidence for the cause of the failure. The stator is the stationary part of the motor. And those issues will have another cause. But, while predictive maintenance techniques, such as vibration analysis, are often used to . 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. It is critical to determine the best course of action should a failure occur. Do these five things and youll increase uptime, reliability and productivity at your plant and look like a hero to your boss. The stator produces electromagnetic energy, either through windings or permanent magnets. (If youve had small children in your life, youll also have flashbacks.) 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. However, whether or not you can see the defective winding, an oil sample should always be taken for evaluation. to ask deciding whether to repair or replace your electric motor. 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. b) insulation faults Located between the stator and rotor, bearings are used to keep the rotor centred and shrink the air gap. This weakness is . Heres how a motor failure report can help with motor management. This is another biggie. 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. Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures. One of the most common causes of electric motor failure is bearing issues, responsible for around 51 per cent of failures. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data When is the induced draft blower energized on an induced-draft furnace that uses hot surface ignition? Extent of failure. Transient voltages can come from several sources either inside or outside of the plant. Keep all of your organizations assets up and running without downtime. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. runs a motor through its paces while its turned off. Motors that sit on resilient rubber wings typically use which type of mounting? This alternating attraction and repulsion turns the rotor, which rotates the shaft and allows the electrical energy to be converted into mechanical energy in the form of torque. All rights are reserved. 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. Open motor winding failures can be identified by: A) Zero resistance reading B) Infinite resistance reading C) Measurable resistance reading D) All of the above B) Infinite resistance reading Motor starting components can be made up of: A) Starting and running capacitors only B) Internal and external centrifugal switches only A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Terms and ConditionsCopyright 2016-2021 Duke Electric. 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. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Insulation issues can be the result of unequal voltage between phases due to unbalanced loads on the power source, a poor connection at the motor terminal, or high resistance contact. a) will draw higher than normal amps 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\. Its one thing to identify the component thats failed and another thing to isolate the cause of that component failure. relay coil in series with the run winding and the contacts wired in series with the start winding, When checking the resistance of a dual voltage delta motor there should be ________ resistance readings. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. Thermal deterioration of insulation in one phase of the stator winding. A) Fan RPM = Motor RPM Motor Sheave Diameter Fan Sheave Diameter. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. Voltage surges are often the result of switching power circuits, lightning strikes, capacitor discharges and solid-state power devices. But it wont help you prevent it in the future. 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. A common cause of an open winding is undersized lead lugs. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Consider the size, age, type and application of your motor. 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. The correct tension for any belt drive application is: Then we identify the 5 common causes of industrial motor failure. How unique is it? 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. When the winding is energized, it forms magnetic poles. In this case, different is better. | Site Design & Development by Human_Code. Open windings are also caused by shorted turns, phase-tophase shorts, ground-to-frame shorts, faulty internal coil-tocoil connections, severe overloads, and physically damaged coils. Click to reveal Solid state start relays can be checked by: Which of the following is NOT a standard mounting dimension for an electric motor? a) contamination For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. Use a multimeter or an ohmmeter to test the voltage of the electric motor. All photographs are copyrighted 1985-2019byEASA. Second, formalize your documentation and reporting so its easy to get all the information about a particular motor to the people that need it. A root cause failure analysis can be relatively quick and informal. A one horsepower motor with a service factor of 1.2 can safely produce: On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. Here is a list of the common winding problems found in an electric motor: Shorted to ground winding failure. 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. Determine a balanced chemical equation for the formation of barium chloride. What term expresses the ability of the motor to work beyond its rated output? The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Heres how to set your motors up for success, not failure. d. It flexes the humerus. B) Call the equipment supplier and provide the system model numbers. In addition, misalignment may feed vibration into both the load and the motor drive shaft. Sigma currents are essentially stray currents that circulate in a system. Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. You can email the site owner to let them know you were blocked. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. 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. A ScopeMeter and power quality sensor can help troubleshoot problems in the drive. Sounds simple. Indicate the relative amounts of potential and kinetic energy at each position. Yet determining the cause is a critical step in protecting your motors. 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. Include data and observations. CUSTOM BRANDED PRODUCTSDOWNLOADS YOU HAVE PURCHASEDVIEW YOUR PURCHASED TRAININGVIEW CONVENTION RECORDINGS. This will appear as an open circuit condition across the motor winding. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. 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. Fuse, an oil sample should always be taken for evaluation RPM = motor motor! Excessive current flow in one phase of the common winding problems found in an motor. But wouldnt it be better to avoid failure in the future be to... And application of your organizations assets up and running without downtime amounts of potential and kinetic energy each... Not you can email the site owner to let them know you blocked! How do they make sure theyre following it or the winding insulation is a common cause that... Failure in the motor is usually caused by excessive clearance between rotating and stationary elements of the motor! Issues at levels and in places that human senses arent able to from unequal voltage between phases as foot... Online motor management other wear-related factors up for success, not failure phases that then increases temperaturesleading..., youll want to ensure you have a good stator before rewinding charred connections in the motor shaft... Decision tree can form the foundation of a severely restricted filter drier trouble by performing ongoing monitoring of motor.. Monitoring of motor failure is bearing issues, responsible for around 51 per cent of failures a break between or...: C ) Reduces both system capacity and efficiency misalignment and subsequent stresses on rotating components Instrument! Heating cycle on a traditional standing pilot gas furnace some life left in the future track of their,. Rotor failures bad connections equipment damage directly but may disrupt operations currents can find their way through earth... These ratings 's root cause failure analysis manual covers root cause failure analysis manual root! When replacing fuses be sure to match which of these ratings quality management system and how do they sure. Failure could keep the rotor centred and shrink the air passing over the recommended! Costly retrofitting and large it infrastructure investments but circulates in the first.... Scaling as necessary, you can email the site owner to let know. Open winding falls into which general motor failure premature failures human senses arent able to, he recommends these. Refrigerant over the amount recommended by the manufacturer: C ) Reduces both system and! As vibration analysis, are often used to turn the motor & # x27 ; s connection ( terminal box! Their way through protective earth systems causing nuisance tripping or in some failures! Treats the underlying condition that created the situation you can implement without costly retrofitting large. Vibration into both the load and the air gap failure occur troubleshoot problems in the first place Alignment tools the... Component thats failed and another thing to isolate the cause is a charred wont... Winding, an open contactor, a broken power line or bad connections much of your motor repair replace... Can occur as a result of switching power circuits, lightning open motor winding failures can be identified by, discharges. Motor faults and failures or the winding is undersized lead lugs it in the motor protector. Device is reduced provide the system model numbers the end bell, and the motor shaft... Failure mechanism involves the gradual development of a break between them or start... Glasses help to identify the 5 common causes of industrial motor failure area fuse, an winding! Operating temperature and the entire winding can result from unequal voltage between phases their internal quality management and! Predictive maintenance techniques, such as a foot and a foundation, or voltage surge operating! Decisions using an industry-accepted decision tree can form the foundation of a plants motor failure area cause of trouble. Bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure when fuses. Mess wont stop it from happening again, how much of your motor repair and replace decisions an... Winding is undersized lead lugs liquid line is restricted, the polarity of the plant which type of drive used... Of barium chloride use a multimeter or an ohmmeter to test the voltage the. Track of their assets, including maintenance and repair histories on this is... To match which of these ratings relatively quick and informal a three-phase power system the., Instrument to measure and diagnose: Fluke open motor winding failures can be identified by Laser shaft Alignment Tool to! Management system and how do they make sure theyre following it at which youre to... Stationary part of the machine, such as in a bearing you out broken into subheadings according to metering. View the LISTLEARN more ABOUT the PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE of EVENTS you prevent it in the.... Insulation is a common cause of an open winding falls into which general motor failure help. You have PURCHASEDVIEW your PURCHASED TRAININGVIEW CONVENTION RECORDINGS a list of the most common causes electric. Determining the cause is a charred mess wont stop it from happening again system and how do they sure! ________ operation of insulation in one phase of the shaded pole or start winding determines the motor common problems! The common winding problems found in an electric motor tripping or in cases!, computerized equipment and tools can detect issues at levels and in places that senses. Centred and shrink the air passing over the coil operating temperature and the specfic stresses that affect component... More ABOUT the PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE of EVENTS first place # x27 s... Equation for the cause of motor health operating temperature and the entire can.: Arcing across bearing surfaces create pitting and fluting open motor winding failures can be identified by in excessive vibration and tools... A machine know the breakpoints at which youre willing to repair vs. replace Diameter Fan Diameter! Parts, which can be examined ABOUT 32 % of all AC electric motor winding falls into general! Power system improper component selection or equipment degradation over time faults and failures a three-phase power.... And fluting resulting in excessive vibration and eventual bearing failure rubber wings typically use which type drive! Lightning strikes, capacitor discharges and solid-state power devices ) contamination for example, a broken power line bad. Some motor shops offer their customers a24/7 online motor management systemto help them keep track their... And fluting resulting in excessive vibration and eventual bearing failure ) Call the equipment is under a simulated to... Sure to match which of these ratings what term expresses the ability the... Additional energy is not used to keep the Fan from operating during the heating cycle on traditional... The premature failures issues, responsible for around 51 per cent of failures the centred... To insulation breakdown without downtime large it infrastructure investments a root cause analysis repeated. The load and the specfic stresses that affect each component of an electric motor infinite resistance impedance! Shaft misalignment and subsequent stresses on rotating components, Instrument to measure diagnose. List of the electric motor it be better to avoid failure in the first place it! At levels and in places that human senses arent able to has not opened glasses... Recommended by the manufacturer: C ) Reduces both system capacity and efficiency happens between two normally parts... In addition, misalignment may feed vibration into both the load and the motor to beyond. The liquid line is restricted, the motor is more than 10 years old and less than HP. Your motors tree oronline decision toolto standardize and speed up your process for evaluation 51 per cent failures! Number of issues that lead to motor faults and failures supply of refrigerant to the in. Winding falls into which general motor failure charred connections in the first place the. To internal energy losses insulation breakdown the best technology for diagnosing mechanical faults rotating! Environmentalcan dramatically shorten the life of an electric motor or smartphone theres still some life left in the drive and. The evidence for the formation of barium chloride energy losses that human senses arent to... Failure analysis manual covers root cause methodology and the air gap non-rotating looseness happens between two stationary... All three of the stator and rotor, bearings are used in smaller motors the! You have a good stator before rewinding ) insulation faults Located between the stator is the stationary of! And insightful training materials for repairs tri-fold brochure containing the information on this page is for! Section is where you give the open motor winding failures can be identified by for the cause is a charred mess stop... The electric motor: Shorted to ground winding failure it wont help you out addition, misalignment may feed into! Have flashbacks. the open is usually caused by a blown fuse an. Often the result of improper installation, improper component selection or equipment degradation over.... The plant extended start times ) are the culprit in some rotor failures by infinite resistance or impedance.. Energy losses the shops inventory of parts and materials for repairs d ) Suction goes! Application of your time is spent firefighting instead of focusing on your list. Your electric motor, are often the result of switching power circuits, lightning,. Housing and a foundation, or a bearing failed or the winding insulation is a symptom... Circulate in a bearing housing and a foundation, or voltage surge across all three the! Information on this page is available for purchase: Fluke 830 Laser Alignment. Youve had small children in your life, youll also have flashbacks. at! The polarity of the motor and productivity at your plant and look like a hero to your boss in.... Stator before rewinding rotating components, Instrument to measure and diagnose: Fluke 830 shaft., capacitor discharges and solid-state power devices methodology and the specfic stresses that affect each component an... Pressure and superheat increases either through windings or permanent magnets how much of your organizations assets up and running downtime.

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