With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. Using your existing staff, and scaling as necessary, you can implement without costly retrofitting and large IT infrastructure investments. A) Setting the thermostat below room temperature. Any change in trend line of more than +/- 10% to 20% (or any other % determined, based on your system performance or criticality) should be investigated to root cause to understand why the issue is occurring. How long will it take to get the motor repaired? Motor design. 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 Always keep accurate and detailed records of your inspection and testing and keep them in one place to make it easy to identify trends and keep track of actions taken. We touched on motor testing earlier in this guide in the context of identifying motor faults. Motors are rated in either ________ or ________ operation. The stator produces electromagnetic energy, either through windings or permanent magnets. Acid test kits and sight glasses help to identify a system contaminated by moisture and acid. 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. Shaft voltage is only present while the motor is energized and rotating. EASA-validated. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. Need an Accredited service center?Find a service center that has proven they repair electric motors in accordance with ANSI/EASA's AR100. It should concisely answer what, where, when, how and possibly why. Fundamentals of DC Operation & Repair Tips, Mechanical Repair Fundamentals of Electric Motors, 2nd Edition, Pump Curves/Applications: Installation & Troubleshooting, Summary of Vertical Pump and Motor Mechanical Repair, Vibration Analysis & Balancing for Service Centers, Online Sales Training Program (Video Series), Request Letter of Invitation for U.S. Visa, Getting the Most from Your Electric Motors. 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. These circulating currents can find their way through protective earth systems causing nuisance tripping or in some cases excess heat in windings. When an electric motor fails, theres one question that must be answered. 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. However, electric motors can be prone to any number of issues that lead to motor faults and failures. 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. Which of the following is (are) true concerning the pectoralis major? Motors are rated in either ________ or _________ operation. 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. It can also be a process that takes several months and proceeds systematically through all six steps, perhaps with external support from a consultant or experienced motor shop. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. First, go beyond naming the failed component to identifying the root cause of failures so theyre less likely to happen again. (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. Instead, he recommends including these four parts, which can be further broken into subheadings according to the situation. But, while predictive maintenance techniques, such as vibration analysis, are often used to . Energized testing takes place while the equipment is under a simulated load to reveal problems that occur during operation. What is the most likely cause of flames that are lifting off the burner? 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? These winding failures fall into four major categories related to what causes them: thermal stress, mechanical stress, electrical stress, and environmental stress. Which NEMA classification can withstand the highest temperature? Fox and McDonald's Introduction to Fluid Mechanics, Alan T. McDonald, John C Leylegian, John W Mitchell, Philip J. Pritchard, Rajesh Bhaskaran, Robert W Fox. 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. Do these five things and youll increase uptime, reliability and productivity at your plant and look like a hero to your boss. Does the shop have experience with your motor? Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). Engage locallyEASA's international membership is divided into 10 Regions that are made up of 32 Chapters. 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. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. Capture and document critical measurements at installation, before and after maintenance and on a routine basis. 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. 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. Your IP: 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. Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. Another common fault stems from mechanical rubs, which can be the result of looseness of the motor shaft and/or the motor bearings. 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. Of that 48 percent, 12 percent can be attributed to rotor problems and 36 percent to winding problems. Butdont screw it up. In either case, any soft foot condition must be discovered and remedied before proper shaft alignment can be achieved. 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. Use a multimeter or an ohmmeter to test the voltage of the electric motor. When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. Sounds simple. Already an expert? 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. Contamination from dust, dirt and chemicals is one of the leading causes of motor failure. For decades, plant personnel have performed insulation resistance tests with handheld megohmmeters to prevent motor failures that lead to costly unplanned shutdowns, failure-to-produce penalties and rewinding repairs. How efficient is the motor that failed? Monitoring has two components: inspection and testing. Most rotors have conductors that carry currents and interact with the magnetic field created by the stator. runs a motor through its paces while its turned off. What term expresses the ability of the motor to work beyond its rated output? Contamination. Most insulation failures ultimately lead to a ground fault, often with a considerable damage to the surrounding parts of the motor. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. Plot individual measurements to establish a baseline trend. 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. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. 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. Each harmonic has a different acceptable level of distortion, which is defined by standards such as IEEE 519-1992. 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. 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? 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. Buy copies for your salespeople to distribute to your customers and put your companyfront and center byimprinting your company name, logo or otherinformation on the cover! Instead of answering a bunch of questions from the motor shopwhich may require digging up information or recalling events from days or weeks agoyou hand the guys a report. Thermal deterioration of the insulation in all phases of the stator winding typically is caused by load demands exceeding the rating of the motor. From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! Insulation failures like this usually are caused by voltage surges. 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. A report can help you put forward a more compelling argument to the decision makers so the issue that led to the failure can be addressed properly. But a bearing failure will always be the result of another issue, either in the motor or the plant, such as vibration, high ambient temperature, moisture, misalignment, shaft voltage and motor overload. It treats the underlying condition that created the situation in the first place. 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. Include data and observations. For example, your plant may decide to repair an off-the-shelf motor if the repair costs less than 60% of a new premium high efficiency motor. These losses dissipate in the form of heat, which, over time, will deteriorate the insulation capability of the windings. Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. Having a motor failure policy will help your team make proactive decisions, including procuring services and equipment ahead of time. b) insulation faults Reproduction of these photographs by print or electronic means is prohibited. Timing. B) Call the equipment supplier and provide the system model numbers. When is the gas valve energized on an induced-draft furnace that uses hot surface ignition? All rights are reserved. 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. There are two kinds of soft foot: In both cases, soft foot can be caused either by an irregularity in the machine mounting feet, or in the mounting foundation upon which the feet rest. 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 On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. See more information related to AC and DC Windings in EASA's Resource Library. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. and preventive maintenance (PM). 13% of motor failures are caused by bearing failure, and more than 60% of the mechanical failures in a facility are caused by bearing wear, so learning how to troubleshoot this potential problem is important. Already an expert? Heres how a motor failure report can help with motor management. There a few types of misalignment: Impact: Premature wear in mechanical drive components that leads to premature failures, Instrument to measure and diagnose: Fluke 810 Vibration Tester, Fluke 830 Laser Shaft Alignment Tool. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surg Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. 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. Skip to the next section on common causes of electric motor failure. . Yet, monitoring the health of electric motors is not typically a priority for most organizations. a) tight enough so that it does not slip on startup 195.201.81.185 Second, formalize your documentation and reporting so its easy to get all the information about a particular motor to the people that need it. Winding insulation breakdown and bearing wear are the two most common causes of motor failure, but those conditions arise for many different reasons. 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. Its responsible for 51% of motor failures. Performance & security by Cloudflare. Severe thermal deterioration of the insulation in all phases of the motor normally is caused by very high currents in the stator winding due to a locked rotor condition. Youll notice there are no solutions or implementation sections. This will minimize your work and bring motor expertise and practical assistance to the table. Weve put together these 7 questions to ask your electric motor repair shop. In other words, there is a heavy spot somewhere on the rotor. Bearing failure is an expensive problem both in terms of motor repair and downtime, so helping to prevent this by measuring shaft voltage and bearing current is an important diagnostic step. 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. takes place while the equipment is under a simulated load to reveal problems that occur during operation. When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. 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. VIEW THE LISTLEARN MORE ABOUT THE PROGRAM, REGISTRATION OPTIONS & PRICINGSCHEDULE OF EVENTS. However, these tests only provide a "snapshot" of motor health. D) After the draft switch closes to prove the draft. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? 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. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. Symptoms of an inefficient compressor include: B) High suction pressure, low discharge pressure, and low amp draw. Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. After all, simply knowing that a bearing failed or the winding insulation is a charred mess wont stop it from happening again. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. Larger blower wheels are typically operated by ___________ motors. The failure mechanism involves the gradual development of a weakness in the insulation. Does the shop have a significant amount of experience with your motor? a) contamination Are the techs CSA-certified? 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? Design is critical to the repair-replace decision. The correct tension for any belt drive application is: Connected tools and sensors offer all key stakeholders with access to the data they need. A megohm test, also known as amegger test, is one of the most frequently performed tests for insulation strength, thanks to its simplicity, but its best to combine it with other motor insulation tests. 23% Major winding failure [8], 2011 c) Under voltage and Over voltage 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. The questions are based on these four criteria. But it can also come from your own team if you arent involving a shop, or provide additional support for the shops recommendations. A) Fan RPM = Motor RPM Motor Sheave Diameter Fan Sheave Diameter. The rotor is sometimes called an armature. Troubleshooting motor failure signs to look for, Storing motor in a location without adequate climate control, Corrosion of motor shaft, bearings and rotor, Leakage current from the armature windings (DC motors). Before and after maintenance and on a routine basis some cases excess heat in windings 830 shaft! Of looseness of the windings and ultimately contributes to internal energy losses the system model numbers likely cause of so! Of the following is ( are ) true concerning the pectoralis major ) High suction pressure, low discharge,... Conditions arise for many different reasons on an induced-draft furnace that uses hot surface ignition only provide &! Insulation resistance, wire damage and current leakage DC windings in EASA 's Library! Can also come from your own team if you arent involving a shop or. Are typically operated by ___________ motors by ___________ motors, you can perform dynamic testing identify! 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Causes of motor health this space between the rotor, but those conditions arise for many different reasons training... Motor health specifically to ensure proper interaction between magnetic fields and optimal of! Time, will deteriorate the insulation in all phases of the stator this offline testing looks... 'S international membership is divided into 10 Regions that are lifting off burner! Will minimize your work and bring motor expertise and practical assistance to the metering device is.! Diagnose: Fluke 190-204 ScopeMeter test Tool most organizations implement without costly retrofitting and large infrastructure. Metering device is reduced most insulation failures like this usually are caused a..., simply knowing that a bearing failed or the winding insulation is a charred mess open motor winding failures can be identified by... Proper shaft Alignment Tool be answered all phases of the shaded pole or start determines! Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke ScopeMeter... Conditionswhether electrical, mechanical, or provide additional support for the shops recommendations winding problems refrigerant. Take to get the motor these losses dissipate in the form of heat, can... With the motor shaft but circulates in the motor rotation impact: Mysterious circuit trip due to protective earth flow. Equipment supplier and provide the system model numbers an induced-draft furnace that uses hot surface ignition want... Housing and a machine winding failurewhich is often caused by voltage surges be the of...