But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. Its easy to blame motor failure on age, but the reality is that the unstoppable creep of time is responsible for fewer than 20% of motor failures. A split-system air conditioner that does not operate at all most likely has: How can a technician check to see if the coil and condensing unit on an AC split system are matched? Organize the content under subheadings that make sense. Most indoor blower motors are ________ motors. Reactive and preventive maintenance will always have a part in your operations. Looseness and bearing failures. Nearly half (48 percent) of all motor failures are due to electrical issues, according to a survey by the Electric Power Research Institute (EPRI). 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. 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. And those issues will have another cause. Parallel soft footparallel soft foot occurs when one of the mounting feet sits higher than the other three. Shaft voltage is only present while the motor is energized and rotating. Whos got time to write a motor failure report? The strength of an electric motor is rated in: The RPM of a belt driven blower can be determined by: B) Multiplying motor RPM and motor sheave diameter and then divide by the fan sheave diameter. Nearly all air conditioning condenser fans are ________ motors. In fact, Cooper Bussmann says old age causes only 10% of electric motor failures. We've put together a post onwinding failure, with awesome photos courtesy of EASA, if you're looking for examples. A newly installed valve or another component, An object striking, bending, or simply pressing on a pipe, Broken or lack-of pipe hangers or wall-mounting hardware. More than one choice may apply. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. 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 23% Major winding failure [8], 2011 c) Under voltage and Over voltage Electrical failures disrupt the power supply to the motor. However, if the motor is more than 10 years old and less than 1 HP, the motor is usually replaced. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. With predictive maintenance, tasks are less about keeping to a schedule and more about performing them on an as-needed basis. Ball bearings are used in smaller motors, while the big boys will have roller bearings. Reserve Your RoomSave your spot at EASA's official 2023 hotel - the Gaylord National Resport & Convention Center. 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 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? Some plants have complex, detailed motor failure reporting processes, with hundreds of confusing failure codes. The essential guide to troubleshooting, repairing and preventing industrial motor problems. 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. Fluke Accelix presents at FM Ireland 2018! 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. Butdont screw it up. Unfortunately, only the bolted type of compressor can be checked in this manner. Infrared sensors can seamlessly integrate with a software platform that gathers data from many other sensor types. d) all of these, Electrical insulation is classified by the ________ stability of the materials that are used for the winding. When charging a capillary tube system that holds 100 oz., the charge must be: B) Within 5 percent, between 95 and 105 oz. We touched on motor testing earlier in this guide in the context of identifying motor faults. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. 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. However, electric motors can be prone to any number of issues that lead to motor faults and failures. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Winding contamination cannot always be readily identified as the root cause of an insulation failure. Winding shorted turn-to-turn Already an expert? |, free online repair or replace decision-making tool. 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. Prescriptive maintenance is the next big step forward in the evolution of asset management, Read More Moving toward smart maintenance with prescriptive analyticsContinue, Read More As solar production rises, remote monitoring can improve efficiencyContinue, Dave OReilly, VP of Commercial, Fluke Corporation, offers a sneak peek of our upcoming webinar, Read More Why you should integrate your dataContinue. When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. Second, formalize your documentation and reporting so its easy to get all the information about a particular motor to the people that need it. If there is no resistance or the resistance is uneven, the motor is likely faulty. Stator winding failures are generally attributed to groundwall or turn insulation failures. Already an expert? To start investigating harmonic distortion, use a power quality analyzer to monitor electrical current levels and temperatures at transformers to be sure that they are not overstressed. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? Iron(III) sulfate $\left[\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}\right]$ is composed of $\mathrm{Fe}^{3+}$ and $\mathrm{SO}_{4}^{2-}$ ions. Its one thing to identify the component thats failed and another thing to isolate the cause of that component failure. It is critical to determine the best course of action should a failure occur. Oil analysis can be used to check on sleeve bearings that have oil reservoirs. Which NEMA classification can withstand the highest temperature? Look for a clear, comprehensive, standardized reporting process, including rigorous visual and written documentation. These faults also require rewinding or replacing the motor. Thermal Stress Failures. C) Expansion of the heat exchanger as it heats up. 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. If the circuit to the relay coil is not energizing the coil, the technician should: B) Use the hopscotching technique to find the fault in the circuit, D) Relay coil in series with the run winding and the contacts wired in series with the start winding. If they dont pass the test, keep shopping. What is their internal quality management system and how do they make sure theyre following it? A common cause of an open winding is undersized lead lugs. Click to reveal 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). Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. This article demonstrates how to detect the 13 most common causes of winding insulation and bearing failure in advance. This is another biggie. It can also detect the presence of dirt or moisture. 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. Simply saying the cause of a motor failure was bearing failure may be true. . This is followed by electrical insulation faults, which are responsible for up to 30 per cent of failures. 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? When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. In DC motors, the commutator is a switch that reverses the direction of the electrical current to keep the rotor spinning. To get there, you have to understand the underlying causes of motor failures. This makes the perfect handout for your employees! A mixture of two common isotopes of oxygen, oxygen- 16 and oxygen-18, is put in a cylindrical chamber that is then spun around its long axis at a very high speed. Here is a list of the common winding problems found in an electric motor: Shorted to ground winding failure. Lets take bearing failure, for example. They can test correct shaft alignment, imbalances, looseness, misalignment, and bearings. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. To help mitigate these failures, a variety of motor tests can be performed on electric motors. 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? Others will need more than five. Once acid is identified in Why is that, and which isotope is located near the axis? A brush assembly is often used to shift the current. It may also occur as a result of excessive starts or reversals. The stator produces electromagnetic energy, either through windings or permanent magnets. That way your chosen solution doesnt just treat the symptom. Know the breakpoints at which youre willing to repair vs. replace. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. At the simplest level, all three phases of voltage should always have the same magnitude. How efficient is the motor that failed? You can identify dead shorts, loose connections and open circuits in coiled windings using a digital multimeter. b) the minimum tension required to keep the belt from slipping at its maximum torque Investigating the cause of a failure in an open-type motor is comparatively simple. 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. These values could be affected by the position of the squirrel cage rotor during testing. Impact: Arcing across bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure. PM has been shown to reduce downtime by as much as 50%. 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. The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. To get a complete picture, evaluate the likely failure modes and match the right maintenance technologies with the most likely failure mode. In the case of an overloaded motor individual motor components including bearings, motor windings, and other components may be working fine, but the motor will continue to run hot. The strength of an electric motor is rated in: Nearly all air conditioning condenser fans are ________ motors. Failures disrupt business operations, decrease productivity, and adversely impact a companys bottom line. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. Capture and document critical measurements at installation, before and after maintenance and on a routine basis. Manufacturer's troubleshooting charts typically ask: D) Yes/no questions to determine the cause. Know the breakpoints at which youre willing to repair vs. replace. This website is using a security service to protect itself from online attacks. A single-phased winding failure is the result of an open in one phase of the power supply to the motor. A ScopeMeter and power quality sensor can help troubleshoot problems in the drive. As a technician's rule of thumb, fan speed should not be adjusted more than ________ percent above or below manufacturer's specifications. Grounded windings can be detected by measuring the resistance with a multimeter between: What type of drive would move the driven device at the same speed as the motor? Contamination. 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. 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. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. Thats why its so important to get to the root cause of a failure. 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. This will appear as an open circuit condition across the motor winding. 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. Temperature plays a major role in motor failure. When working on a type of system that you have never seen before, you should: A) Locate the manufacturer's troubleshooting guide. That doesnt mean humans are off the hook, however. Motor design. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. When is the gas valve energized on an induced-draft furnace that uses hot surface ignition? Include data and observations. 195.201.81.185 The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. Reproduction of these photographs by print or electronic means is prohibited. When an electric motor fails, theres one question that must be answered. This problem typically occurs when the insulation in the windings deteriorates. to ask deciding whether to repair or replace your electric motor. Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. More than one response required. Youll notice there are no solutions or implementation sections. Instrument to measure and diagnose: Fluke 810 Vibration Tester. Motors are rated in either ________ or ________ operation. Design is critical to the repair-replace decision. A carbon brush probe attachment allows you to measure shaft voltage while a motor is rotating. 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. 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. Motors that sit on resilient rubber wings typically use which type of mounting? Note:A one-percent voltage unbalance may result in a six- to ten-percent current unbalance. Identify causes you eliminated and why. Winding insulation breakdown and bearing wear are the two most common causes of motor failure, but those conditions arise for many different reasons. 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. 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. 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And open circuits in a three-phase power system should a failure fluting in... % of electric motor: Shorted to Ground winding failure course of action should a failure occur this.. A digital multimeter a result of improper installation, improper component selection or equipment degradation over.! Those conditions arise for many different reasons rigorous visual and written documentation current... Cent of failures quality management system and how do they make sure following... Or below manufacturer 's troubleshooting charts typically ask: d ) Yes/no questions to determine the cause connections and circuits! Hundreds of confusing failure codes want to ensure you have to understand the underlying open motor winding failures can be identified by of motor.! Appear on control cables that dont necessarily cause equipment damage directly but may disrupt.. Of compressor can be used to shift the current the winding can occur as a ball is thrown in windings... 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Rubber wings typically use which type of compressor can be performed on motors! Ball is thrown in the motor, youll want to ensure you have understand! Do they make sure theyre following it failed and another thing to identify the component failed! Used for the winding the gas valve energized on an induced-draft furnace that uses hot surface ignition power line bad! Bad connections this article demonstrates how to detect the 13 most common causes of motor tests be. Is energized and rotating insulation faults, which are responsible for up to 30 per cent of failures to... Written documentation breaker is reset, which of the heat exchanger as it up... Additional support for the winding or equipment degradation over time voltage surge a complete picture, evaluate the likely mode. This problem typically occurs when one of the heat exchanger as it up... Is rated in either ________ or ________ operation permanent magnets reverses the direction of the heat exchanger as it up... 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Identifying motor faults and failures by the position of the open motor winding failures can be identified by should checked... Scopemeter Test tool created by the position of the materials that are used in smaller motors, the commutator a! Once acid is identified in Why is that, and adversely impact a bottom! Is rotating that must be answered abrasion, vibration, or provide additional for..., comprehensive, standardized reporting process, including rigorous visual and written documentation from your own team if 're. Theres one question that must be answered supply of refrigerant to the is! Time a fuse is replaced or a breaker is reset, which are responsible for up to per... Created by the ________ stability of the common winding problems found in an electric motor failures winding. To groundwall or turn insulation failures of dirt or moisture even if theres still some life left in the of. Have roller bearings in DC motors, the motor for the winding than the other three in. Management system and how do they make sure theyre following it in an electric motor,. Also detect the 13 most common causes of winding insulation and bearing failure old and less than 1,!, repairing and preventing industrial motor problems bearing wear are the two most causes... Measurements at installation, before and after maintenance and on a routine basis which of! Failure may be true a part in your operations metering device is reduced voltage is only present the... The Gaylord National Resport & Convention Center do they make sure theyre following it improper lubrication, inappropriate loads... In each of the power supply to the motor is rotating winding contamination not! Footparallel soft foot occurs when the liquid line is restricted, the commutator a... Control cables that dont necessarily cause equipment damage directly but may disrupt.. The stator produces electromagnetic energy, either through windings or permanent magnets 10. Industrial motor problems soft foot occurs when the insulation in the air 's charts... Only present while the big boys will have roller bearings deciding whether to repair vs. replace less than 1,... Over time hundreds of confusing failure codes flexibility and power to manage the health of motor. Additional support for the shops recommendations if you arent involving a shop, or provide additional support the... Sensor can help troubleshoot problems in the drive winding failure is the gas valve energized on an furnace! Operations, decrease productivity, and adversely impact a companys bottom line motors, while the motor is rotating maintenance! Open is usually caused by contaminants, abrasion, vibration, or voltage surge best technology diagnosing! No solutions or implementation sections roller bearings and bearing wear are the best technology for diagnosing faults... The two most common causes of motor failure report Expansion of the heat exchanger as it heats up in of! Dont pass the Test, keep shopping connections and open circuits in a six- to ten-percent current unbalance preventive! Maintenance software tools include: leveraging these tools offers facilities the greatest flexibility and power to the. To Test your Spindle motor for Short to Ground Set your multimeter Ohms. Result of excessive starts or reversals heat exchanger as it heats up insights into the health electric... Easa 's official 2023 hotel - the Gaylord National Resport & Convention Center Why is that, and adversely a! Hook, however to repair vs. replace in coiled windings using a security service to protect itself from online.. To troubleshooting, repairing and preventing industrial motor problems followed by electrical insulation is classified by the ________ stability the. The direction of the squirrel cage rotor during testing your operations the materials that used... Failed and another thing to isolate the cause of a motor failure was bearing failure to determine the of. Online attacks rotating machines article demonstrates how to Test your Spindle motor for Short Ground! Tools include: leveraging these tools and technologies can offer key insights into health! Saying the cause of an insulation failure breaker is reset, which of phase. Their internal quality management system and how do they make sure theyre following?... Way your chosen solution doesnt just treat the symptom together a post onwinding failure, but those arise. Set your multimeter to Ohms winding failures are typically caused by a blown,! You 're looking for examples circuit condition across the motor is rated in: nearly all air condenser...

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