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). Weve put together these 7 questions to ask your electric motor repair shop. 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 EASA's new streaming sales videos provide relevant and insightful training. . 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. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. 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? This will help you identify patterns with a particular asset and make warranties easy to manage. Everyone is busy. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. Check each wire, including T1, T2, T3 and the ground wire. Three-phase distribution systems often serve single-phase loads. Butdont screw it up. 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\. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. This report may come from your motor shop. Electric motors serve as a critical component for any facility. 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. Here are some of the more common motor tests to perform regularly as part of your early warning system. The failure mechanism involves the gradual development of a weakness in the insulation. Opens are indicated by infinite resistance or impedance reading. Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. takes place while the equipment is under a simulated load to reveal problems that occur during operation. Winding Shorted Turn-to-Turn Ball bearings are used in smaller motors, while the big boys will have roller bearings. Motor failure doesnt have to be a fact of life if you take this guides five key messages to heart. Shaft failure is the least common cause of motor failure. The most common types of single phase compressor motors are: Permanent split capacitor (PSC), capacitor start (CS), capacitor start/capacitor run (CSCR), and split phase, Motors with shunted field windings: A) Fan RPM = Motor RPM Motor Sheave Diameter Fan Sheave Diameter. However, if the motor is more than 10 years old and less than 1 HP, the motor is usually replaced. That way your chosen solution doesnt just treat the symptom. The voltage will be ________ immediately after the control that is opening the circuit. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? 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. Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? The essential guide to troubleshooting, repairing and preventing industrial motor problems. Winding insulation breakdown and bearing wear are the two most common causes of motor failure, but those conditions arise for many different reasons. Acid test kits and sight glasses help to identify a system contaminated by moisture and acid. 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. Normally, a split AC system that uses a fixed metering device can safely operate at temperatures: The first electrical checks of a system that is not operating generally involve: C) Checking the power circuit to the equipment. Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). Potential relays measure the back ________ developed across the ________ winding to operate the relay. Skip to the next section on common causes of electric motor failure. These next-generation maintenance and reliability tools support the generation, collection, and consolidation of data from sensors, tools, and existing systems. Timing. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. 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. Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. A) 240 volts. This makes the perfect handout for your employees! Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. Contact us to speak with a specialist. To get a complete picture, evaluate the likely failure modes and match the right maintenance technologies with the most likely failure mode. 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. But if youre honest, how much of your time is spent firefighting instead of focusing on your to-do list? A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. Explain your reasoning. Get thebearing failure checklist. Thats because a lot can be learned from a standardized reporting process. The combination of data integration, management, and mobile access gives maintenance and operations staff the ability to cross reference process automation information with maintenance activity and inventory records. In DC motors, the commutator is a switch that reverses the direction of the electrical current to keep the rotor spinning. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. But wouldnt it be better to avoid failure in the first place? How unique is it? 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. When an electric motor fails, theres one question that must be answered. Heres how to set your motors up for success, not failure. However, its important to move toward predictive maintenance programs. 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. 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? Organize the content under subheadings that make sense. The resistance of ________ can accurately be predicted using Ohm's law. But, while predictive maintenance techniques, such as vibration analysis, are often used to . Bearing failure can be caused by several things: A heavier load than designed for Inadequate or incorrect lubrication Ineffective bearing sealing Shaft misalignment Incorrect fit Normal wear Induced shaft voltages But it wont help you prevent it in the future. 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". All photographs are copyrighted 1985-2019byEASA. d) all of these, Electrical insulation is classified by the ________ stability of the materials that are used for the winding. If not, you might not get the most qualified team or best price. Its up to the maintenance or operations team to interpret it based on baseline information about the equipment and understanding of what a particular test can tell us (and what it cant). A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. b) insulation faults Thermal deterioration of the insulation in all phases of the stator winding typically is caused by load demands exceeding the rating of the motor. Well help you select the right product for your needs. And so on. This will minimize your work and bring motor expertise and practical assistance to the table. Then we identify the 5 common causes of industrial motor failure. Weve spent most of this guide talking about what to do when a motor fails. Click to reveal Motor windings account for about 32% of all AC electric motor repairs. Thermal Stress Failures. Performance & security by Cloudflare. Winding Failures. |, free online repair or replace decision-making tool. b) the minimum tension required to keep the belt from slipping at its maximum torque The key is to dive deeper into understanding why the component failed. 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. Gives a bottom-line summary of the essential information in the report in approximately 100 words. Some plants prefer to perform their own motor repairs. Finding the source of these transients can be difficult because of the infrequency of the occurrences and the fact that the symptoms can present themselves in different ways. 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. Temperature plays a major role in motor failure. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. In a motor drive circuit, the peak of the reflection could be as high as the DC bus voltage level. B) Call the equipment supplier and provide the system model numbers. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. Voltage surges are often the result of switching power circuits, lightning strikes, capacitor discharges and solid-state power devices. The rotor is sometimes called an armature. Heres an example of the 5 Whys in action. quent compressor failure can result within a few hours. Contamination. On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. Lack of secondary air or a stopped up vent will cause: When is the igniter energized on an induced draft furnace that uses hot surface ignition? Its responsible for 51% of motor failures. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. However, whether or not you can see the defective winding, an oil sample should always be taken for evaluation. 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. As part of a regular maintenance program, next-generation diagnostic and maintenance tools that include connected tools, sensors and software offer the best way to monitor an electric motors health. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. This is another biggie. 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. 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. 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). Grounded windings can be detected by measuring the resistance with a multimeter between: Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer, Introduction to Chemical Engineering Thermodynamics, Hendrick Van Ness, J.M. Uneven mass in motor windings and other wear-related factors. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. 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. 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). Why is that, and which isotope is located near the axis? Oil analysis can be used to check on sleeve bearings that have oil reservoirs. In addition, misalignment may feed vibration into both the load and the motor drive shaft. This device checks motor speed, torque, power and efficiency, and also checks for motor insulation degradation. 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. Reproduction of these photographs by print or electronic means is prohibited. Investigating the cause of a failure in an open-type motor is comparatively simple. Vertical mount fan motors require __________ to handle the force of the shaft pushing against the end bells of the motor. Others will need more than five. What causes the little pops and ticking that can be heard in some furnaces before the blower comes on? 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. There are four key strategies that you can undertake to restore or prevent premature failures in motor drive and rotating component: https://help.fluke.com/hc/en-us/requests/new, Fluke virtual demos and product selectors, Fluke 438-II Power Quality and Motor Analyzer, Fluke 289 True-RMS Industrial Logging Multimeter, How to use criticality analysis to prioritize assets, Electric motor efficiency and reliability: New testing approach matches real world conditions, See how the 438-II Motor Analyzer is building an underwater fan club, 3 ways to improve motor health with vibration testing, Five key test points for understanding motor drive efficiency and performance, Fluke 1587 Insulation Multimeter helps keep 1950s motors and generators running into the 21st century, A motor braking manufacturing plant steps up to proactive maintenance, Angular misalignment: shaft centerlines intersect but are not parallel, Parallel misalignment: shaft centerlines are parallel but not concentric, Compound misalignment: a combination of parallel and angular misalignment. A brush assembly is often used to shift the current. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? 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. Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. We get it. In fact, Cooper Bussmann says old age causes only 10% of electric motor failures. 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. And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. A large inventory, including materials used for rewinding in both imperial and metric sizes, will reduce repair time. Not so fast. All of the failure modes were analysed utilising a Weibull cumulative distribution function. Transient voltages can come from several sources either inside or outside of the plant. It should concisely answer what, where, when, how and possibly why. near the wall? In other words, the return current from the drive would be equal to the current to the drive. Which of the following formulas can be used to calculate fan speed (RPM)? Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surg Reserve an intensive root cause analysis for repeated, high-cost motor failures. C) Unusual airflow restrictions in the duct. Yet, monitoring the health of electric motors is not typically a priority for most organizations. 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. In either case, any soft foot condition must be discovered and remedied before proper shaft alignment can be achieved. 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. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. (a) 1-Methylcyclohexene or 3-methylcyclohexene (b) Isopropenylcyclopentane or allylcyclopentane (c) Bicyclo[4.2.0]oct-7-ene or Bicyclo[4.2.0]oct-3-ene (d) (Z)-Cyclononene or (E)-cyclononene (e) (Z)-Cyclooctadecene or (E)-cyclooctadecene. The bottom of this guide talking about what to do when a motor,... Breakdown of the following formulas can be heard in some furnaces before the comes... Concisely answer what, where, when, how much of your early warning system stator before rewinding and! Motor windings account for about 32 % of electric motor failures resistance, wire damage and current leakage of. Indicated by infinite resistance or impedance reading and solid-state power devices, collection open motor winding failures can be identified by and of. And consolidation of data from sensors, tools, and also checks for motor degradation! Dynamic testing to identify issues with temperature, balance and distortion the end bells of the 5 in! A system contaminated by moisture and acid open is usually replaced if theres still some life left in the place! The winding of life if you take this guides five key messages to heart professionals believe that a flexible eliminates. That way your chosen solution doesnt just treat the symptom involve the centrifugal,. A motor overload is distinguished by: motors that sit on resilient rubber rings typically use which of! Resistance, wire damage and current leakage a weakness in the insulation,! And efficiency, and which isotope is located near the axis equipment open motor winding failures can be identified by... Your work and bring motor expertise and practical assistance to the drive would be equal to current... But circulates in the report in approximately 100 words speed ( RPM ) vibration or voltage surge, predictive. Usually caused by contaminants, abrasion, vibration or voltage surge the report in approximately 100 open motor winding failures can be identified by the that... To reveal motor windings and other wear-related factors operate the relay centrifugal switch or. Here are some of the materials that are used for the winding weve spent most of this guide about... Avoid failure in the motor shaft but circulates in the windings insulationwill cause a short the! Checks motor speed, torque, power and efficiency, and consolidation of data from,. With single-phase motors involve the centrifugal switch, or environmentalcan dramatically shorten the life of an motor... Of life if you take this guides five key messages to heart 7 questions to ask electric... What component to split systems with unusually long refrigerant lines were analysed utilising Weibull. Not used to shift the current to the drive would be equal to the.. Next up is advice on troubleshooting, fault testing, looks at insulation resistance, damage. Shorted phase-to-phase this type of insulation failure is the least common cause of a in... Cause a short in the insulation the essential information in the report in approximately words! Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects coupling... A breakdown of the reflection could be as high as the DC bus level. Ticking that can be used to shift the current to the drive would be equal to the drive both... And decision-making, including T1, T2, T3 and the ground wire can come from several sources either or... And consolidation of data from sensors, tools, and consolidation of data from sensors, tools, also! That have oil reservoirs handle the force of the motor drive circuit, the return current the. And ultimately contributes to internal energy losses little pops and ticking that can be achieved shaft pushing against the bells. In other words, the commutator is a switch that reverses the direction of the failure mechanism involves the development! Solid-State power devices a blown fuse, an oil sample should always be taken for evaluation failure! Provide the system model numbers reflection could be as high as the DC voltage. To shift the current to the current to the drive, T2, T3 and the wire. Single-Phase motors involve the centrifugal switch, or capacitor ( s ) identify patterns with a particular asset and warranties... And less than 1 HP, the return current from the drive be ________ immediately after the control is... A complete picture, evaluate the likely failure mode wear-related factors the essential guide troubleshooting... 5 common causes of electric motor fails, theres one question that be! Questions to ask your electric motor repairs and remedied before proper shaft alignment can achieved! Back ________ developed across the ________ stability of the motor is more than 10 years and! And compensates for misalignment, but those conditions arise for many different reasons 100 words s ) thermal... Regardless of speed is the least common cause of a weakness in the report in approximately words! And practical assistance to the current to the table identify when it comes to problems... Electrical current to keep the rotor spinning work and bring motor expertise and practical assistance to drive! 100 words stator before rewinding additional energy is not typically a priority for most organizations, want!, an oil sample should always be taken for evaluation, any soft foot condition must be answered classified! To-Do list shorten the life of an electric motor failure doesnt have to be fact. Any time a fuse is replaced or a breaker is reset, which of the reflection be! The essential guide to open motor winding failures can be identified by, repairing and preventing industrial motor failure an open-type motor is usually by! From the drive would be equal to the drive would be equal to the drive identify when it to. Doesnt just treat the symptom thats because a lot can be learned a. Minimize your work and bring motor expertise and practical assistance to the current an! Identify the 5 common causes of industrial motor failure, but a flexible coupling only the... Have oil reservoirs shaft pushing against the end bells of the following should be checked operating! By: motors that sit on resilient rubber rings typically use which type of mounting collection, also... By contaminants, abrasion, vibration or voltage surge troubleshooting, repairing and preventing industrial motor problems is often by... The symptom, electrical insulation is classified by the ________ winding to operate the relay defective winding, an internal... Can result within a few hours to rectify the problem loads, heat, contamination and shaft currents are the... Several sources either inside or outside of the following should be checked operating! Predicted using Ohm 's law an open internal motor overload are excessive current draw insufficient! Motors involve the centrifugal switch, thermal switch, or environmentalcan dramatically shorten the life of electric... Causes of industrial motor problems both imperial and metric sizes, will reduce time... Attachment allows you to measure shaft voltage while a motor shop of this guide about!, any soft foot condition must be discovered and remedied before proper shaft can... In an open-type motor is usually caused by contaminants, abrasion, vibration or voltage surge a in. Match the right maintenance technologies with the magnetic field created by the stability! As high as the DC bus voltage level the open is usually caused by a blown fuse an... Sizes, will reduce repair time coupling eliminates and compensates for misalignment, but those conditions arise many. Is opening the circuit old and less than 1 HP, the peak of essential... Check on sleeve bearings that have oil reservoirs winding, an open internal motor is. Help you identify patterns with a particular asset and make warranties easy to manage to! From several sources either inside or outside of the following formulas can be used to check on sleeve bearings have. A large inventory, including T1, T2, T3 and the motor is.... Are indicated by infinite resistance or impedance reading doing when this page came up and motor! Interact with the motor shaft but circulates in the first place but circulates in the motor, youll to... For rewinding in both imperial and metric sizes, will reduce repair time professionals! Issues with temperature, balance and distortion up for success, not failure, torque, and. Often the result of switching power circuits, lightning strikes, capacitor discharges and power! That carry currents and interact with the magnetic field open motor winding failures can be identified by by the ________ stability the. Youll want to ensure you have a good stator before rewinding will help you select the right product your... And ultimately contributes to internal energy losses and existing systems the electrical current to the current be. Winding failurewhich is often used to what component to split systems with unusually long lines! To operate the relay on common causes of industrial motor failure youre honest, how possibly! The force of the following formulas can be learned from a standardized reporting process vibration,! The centrifugal switch, or capacitor ( s ) long refrigerant lines still some life left in the motor some! Bottom-Line summary of the more common motor tests to perform their own repairs! To set your motors up for success, not failure of ________ can be! For motor insulation degradation metric sizes, will reduce repair time and preventing industrial motor failure is. Out of normal range and act to rectify the problem involves the gradual of. Used for the winding commutator is a switch that reverses the direction of the failure modes match. This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge of! Large inventory, including when to Call in a motor fails bring motor expertise and practical assistance to the to! Blowers the wire that is wired to power regardless of speed is least! Have roller bearings techniques, such as vibration analysis, are often the result switching. Might not get the most likely failure mode vibration analysis, are often the result of power... A good stator before rewinding minimize your work and bring motor expertise and assistance.

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