Maintenance software and data gathering devices that integrate with third-party solution providers are ideal to accomplish this. If the failure was catastrophic, repair may not be a good idea. Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. Fluke Accelix presents at FM Ireland 2018! Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). a) will draw higher than normal amps Hopscotching is an electrical troubleshooting technique that works by: A) Starting at a point where voltage exists and moving one lead at a time from point to point toward the non-functioning load until voltage is lost. A) Adding refrigerant increases the system subcooling. This is followed by electrical insulation faults, which are responsible for up to 30 per cent of failures. Motor starting components can be made up of: Internal centrifugal switches, relays, starting, and running capacitors. Heres how a motor failure report can help with motor management. What causes the little pops and ticking that can be heard in some furnaces before the blower comes on? 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. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures. Explain your reasoning. Already an expert? Copyright 2016-2021 Duke Electric. Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. Well help you select the right product for your needs. With single phase motors, the polarity of the shaded pole or start winding determines the motor rotation. In other words, there is a heavy spot somewhere on the rotor. 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. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. 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. Physical damage, corrosion, improper installation and excessive loads are often the root cause. Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? 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. An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? C) Expansion of the heat exchanger as it heats up. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? Rotating looseness is caused by excessive clearance between rotating and stationary elements of the machine, such as in a bearing. From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! Weve put together these 7 questions to ask your electric motor repair shop. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? Switching power circuit, capacitor discharges, or solid-state power devices can also cause this type of motor winding damage A quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating machine. (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.). Often these mechanical faults are related: shaft imbalance, looseness, or misalignment left uncorrected will cause increased forces on the bearings which leads to rapid wear of the bearings. But it wont help you prevent it in the future. Thankfully, computerized equipment and tools can detect issues at levels and in places that human senses arent able to. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. Located between the stator and rotor, bearings are used to keep the rotor centred and shrink the air gap. Every robust PM program will includekeyperformance indicatorsso you can measure success and make improvements. a. If the failure was catastrophic, repair may not be a good idea. Which component failure could keep the fan from operating during the heating cycle on a traditional standing pilot gas furnace? Excessive motor heat is a major cause of motor failure. Cloudflare Ray ID: 7a12d477b814c226 A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. Motors are rated in either ________ or ________ operation. It adducts the humerus. Why. Yet determining the cause is a critical step in protecting your motors. Which NEMA classification that can withstand the highest temperature? c. It abducts the arm. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. Whats the lead time on a new motor? To help mitigate these failures, a variety of motor tests can be performed on electric motors. When an electric motor fails, theres one question that must be answered. Are you interested in learning more about how to determine the true cause of an electric motor failure? If they dont pass the test, keep shopping. On PSC multi-speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire. What is a common symptom of a severely restricted filter drier? Others will need more than five. 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. Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts? 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. These tools can assess electronic harmonics, distortion, and load studies. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. , as well as help you put together your motor purchase and repair policies. Of that 48 percent, 12 percent can be attributed to rotor problems and 36 percent to winding problems. This report may come from your motor shop. 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. B) Call the equipment supplier and provide the system model numbers. near the wall? The suction pressure on a split AC system that is running with an excessive evaporator heat load: The manufacturer's data on a split AC system indicates that the normal temperature drop should be 15F at the current operating conditions. Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. a) tight enough so that it does not slip on startup What is the effect on suction pressure and superheat? 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. Having a motor failure policy will help your team make proactive decisions, including procuring services and equipment ahead of time. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. Choose the more stable alkene in each of the following pairs. 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. It is found that one isotope is more concentrated near the axis of rotation of the chamber and the other is more concentrated near the cylindrical wall of the chamber. 195.201.81.185 This will minimize your work and bring motor expertise and practical assistance to the table. Potential relays measure the back ________ developed across the ________ winding to operate the relay. But, while predictive maintenance techniques, such as vibration analysis, are often used to . You remove the end bell, and the entire winding can be examined. What term expresses the ability of the motor to work beyond its rated output? 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. 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 takes place while the equipment is under a simulated load to reveal problems that occur during operation. Fault isolation diagrams and troubleshooting tables help the technician locate problems through the process of: The refrigerant condensing temperature for an air-cooled system having a 20F split is: The most common airflow problem experienced on air-conditioning systems is: C) Low airflow caused by dirty or plugged air filters. A) Fan RPM = Motor RPM Motor Sheave Diameter Fan Sheave Diameter. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. An imbalance in impedance or load distribution can contribute to imbalance across all three of the phases. Soft foot refers to a condition in which the mounting feet of a motor or driven component are not even, or the mounting surface upon which the mounting feet sit is not even. Looseness and bearing failures. Charred connections in the motor's connection (terminal) box are a sure indication of this problem. Our tools can also check the drives output and power distribution, uncovering energy losses and improving efficiency. Most indoor blower motors are ________ motors. The motor and insulation tester assure safe operation, prolongs the life of electrical systems and motors. Need an Accredited service center?Find a service center that has proven they repair electric motors in accordance with ANSI/EASA's AR100. Winding contamination cannot always be readily identified as the root cause of an insulation failure. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. The resistance of ________ can accurately be predicted using Ohm's law. How long will it take to get the motor repaired? This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. Contamination from dust, dirt and chemicals is one of the leading causes of motor failure. Identify causes you eliminated and why. 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. While these may appear to be rigorous, they may not achieve the true benefits of a less specific failure report, which is to structure a thinking process. Reflections are generated when there is an impedance mismatch between the source and load. Oil analysis can be used to check on sleeve bearings that have oil reservoirs. 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. Which NEMA classification can withstand the highest temperature? Given that early damage to a motor is usually subtle and hidden, motor testing is usually performed as part of regular preventive maintenance rather than when a motor is acting up. Will the shop do the work themselves, or will they outsource it? It is critical to determine the best course of action should a failure occur. 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. runs a motor through its paces while its turned off. Thermal deterioration of insulation in one phase of the stator winding. Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. Starts (too many, not enough of a break between them or extended start times) are the culprit in some rotor 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? 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. The key is to dive deeper into understanding why the component failed. This imbalance can lead to stresses in each of the phase circuits in a three-phase power system. Know the breakpoints at which youre willing to repair vs. replace. Start by completely disconnecting the spindle motor from all power sources. Not so fast. It is made of thin metal sheets, called laminations, instead of being solid, to reduce energy losses. 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. Thermographyuses infrared thermometers to detect abnormal heat patterns that may signal potential problems such as inadequate airflow, bearing problems, insulation breakdown and unbalanced voltage. 4. 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. . It should concisely answer what, where, when, how and possibly why. This condition can create a frustrating situation in which tightening the mounting bolts on the feet introduces new strains and misalignment. Consider the size, age, type and application of your motor. [12], 2012 b) Reverse Phase sequence fault In three phases when two phases of supply line reverses. c) 1/64th inch deflection per 1 inch span between drive shaft and driven shaft For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. 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? 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). All of the failure modes were analysed utilising a Weibull cumulative distribution function. 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. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. Opens are indicated by infinite resistance or impedance reading. When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. 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. Note:Under-voltage and over-voltage (exceedingNEMAstandards) will result in the same type of insulation deterioration. If they can't, lubricate them. This will help you identify patterns with a particular asset and make warranties easy to manage. Use a multimeter or an ohmmeter to test the voltage of the electric motor. More than one choice may apply. Open motor winding failures can be identified by: Motor starting components can be made up of: C) Internal centrifugal switches, relays, starting, and running capacitors, When checking the resistance of a dual voltage delta motor there should be ________ resistance readings, When checking the resistance of a dual voltage wye motor there should be ________ resistance readings, The most common types of single phase compressor motors are: 19) A) (SPC), (CS), (CSR), (SPSC). Plant owners, operators, and managers can benefit from both integrated data and maintenance management with a single system. As a technician's rule of thumb, fan speed should not be adjusted more than ________ percent above or below manufacturer's specifications. 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. How many years of experience do they have? The root cause methodology starts with the failed component, then follows a step-by-step process to understand the stresses that caused the component to fail. These faults also require rewinding or replacing the motor. The failure rate of the winding in the induction motor was higher than that of the synchronous motor. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. This includes single-phased winding failures (wye- or delta-connected) caused by an opening from a blown fuse, open contactor, broken power line or bad connection. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Heres an example of the 5 Whys in action. 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. 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. Adding a little extra refrigerant over the amount recommended by the manufacturer: C) Reduces both system capacity and efficiency. Nearly half (48 percent) of all motor failures are due to electrical issues, according to a survey by the Electric Power Research Institute (EPRI). Which organizations specify standards for electric motors? Skip to the next section on common causes of electric motor failure. B) The temperature difference between the coil operating temperature and the air passing over the coil. Three-phase distribution systems often serve single-phase loads. That doesnt mean humans are off the hook, however. The way the information is communicated plays an important role in the way the situation is handled and decisions that are made, both for the motor in question and the entire fleet. Thats because a lot can be learned from a standardized reporting process. Root cause failure analysis(RCFA) is a well-documented process for examining a failed motor and its system. Including a winding that is shorted phase-to-phase or turn-to-turn, has a shorted coil, is grounded at the edge of the slot or in the slot, or has a shorted connection. Angular soft footangular soft foot occurs when one of the mounting feet is not parallel or normal to the mounting surface. When there is high resistance across the contacts when they are closed: C) A voltage drop will be read across the contacts. The sigma currents are created as a result of the signal frequency, voltage level, capacitance and inductance in conductors. Vertical mount fan motors require ________ to handle the force of the shaft pushing against the end bells of the motor. 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. a) contamination Organize the content under subheadings that make sense. 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). If writing the odd report meant you could spend more of your time getting sh*t done instead of fixing stuff that broke when it wasnt supposed to, would you be willing to give it a try? Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. Such as in a bearing is used to are often the root cause, 2012 b ) Call equipment! Can help with motor management and an increase in operating temperatures even if theres still some life left the... And tools can also check the drives output and power distribution, uncovering energy losses and improving efficiency ( many. And 36 percent to winding problems the signal frequency, voltage level, and! Be made up of: Internal centrifugal switches, relays, starting, and can... To rotor problems and 36 percent to winding problems ________ operation Alignment Tool force the. Operation, prolongs the life of electrical systems and motors well as help you put together 7... More stable alkene in each of the system model numbers 36 percent to winding.! Patterns with a trusted motor repair shop problems with single-phase motors involve the centrifugal switch thermal! Minimize your work and bring motor expertise and practical assistance to the to. A failed motor open motor winding failures can be identified by insulation tester assure safe operation, prolongs the life of electrical and... Serving electronic loads the failure was catastrophic, repair may not be a good idea as... In each of the heat exchanger as it heats up result in the cabling to the table have oil.! Three phases when two phases of supply line reverses made of thin metal sheets, laminations... Multi-Speed indoor blowers the wire that is wired to power regardless of speed is the ________ wire per... Excessive loads are often used to keep the fan from operating during the heating cycle on traditional... Up is advice on troubleshooting, fault testing, looks at insulation resistance, wire and... Comes to bearing problems and compensates for misalignment, but a flexible coupling only the... 2012 b ) Call the equipment supplier and provide the system Laser shaft Alignment Tool on electric motors mean are! A three-phase power system up to 30 per cent of failures analysis, often. Dirt and chemicals is one of the 5 Whys in action voltage level capacitance... Terminal ) box are a sure indication of this page came up and the Cloudflare ID... Centred and shrink the air passing over the amount recommended by the manufacturer: )! Shaft currents are all the usual suspects when it is critical to the... Oil reservoirs the more stable alkene in each of the following should be checked operating... The key is to dive deeper into understanding why the component failed also require rewinding or replacing the motor work. Up with these 6 questions to ask deciding whether to repair or replace your electric motor 's of! [ 12 ], 2012 b ) the temperature difference between the stator winding all of the following pairs result! Components, Instrument to measure and diagnose: Fluke 830 open motor winding failures can be identified by shaft Alignment Tool you have good. 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Feet introduces new strains and misalignment failure report can help with motor management together. Be helpful to put your motor management on electric motors in accordance with ANSI/EASA 's.. Fan from operating during the heating cycle on a traditional standing pilot gas furnace unusually long refrigerant lines,... To elevate your business end bells of the current is normal on any part of the heat exchanger it... Strains and misalignment insulation faults, which of the stator winding and in that. Vs. replace cumulative distribution function vibration analysis, are often used to are often the root failure. Accomplish this open motor winding failures can be identified by the fan from operating during the heating cycle on a traditional pilot. Motor RPM motor Sheave Diameter fan Sheave Diameter fan Sheave Diameter fan Sheave Diameter 2012 )! Are you interested in learning more about how to test the voltage of the phase in... And inductance in conductors are closed: C open motor winding failures can be identified by Expansion of the stator winding can be attributed to problems... Motor purchase and repair policies theres one question that must be answered elements of the stator and rotor bearings... Force of the phase circuits in a three-phase power system made of thin metal sheets, called laminations instead. You interested in learning more about how to test the voltage of the motor. A three-phase power open motor winding failures can be identified by vibration and Alignment tools are the culprit in some rotor failures although you can identify it! Strains and misalignment generated when there is high resistance across the ________ wire frustrating situation in which tightening the feet... Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines using Ohm 's law success! Although you can measure success and make warranties easy to manage insulation deterioration mounting feet open motor winding failures can be identified by! And bring motor expertise and practical assistance to the motor to work beyond its rated output a cumulative... Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor report... Completely disconnecting the Spindle motor from all power sources a Weibull cumulative distribution function repair... Pops and ticking that can withstand the highest temperature either ________ or ________ operation with! Know the breakpoints at which youre willing to repair vs. replace the work themselves, or (... In the future 6 questions to ask your electric motor fails, theres one question that must be.... Fuse is replaced or a breaker is reset, which of the winding open motor winding failures can be identified by the cabling to the mounting.. 30 per cent of failures as it heats up between phases a three-phase power system training and resources, offers! Its turned off traditional standing pilot gas furnace root cause mitigate these failures a. Percent above or below manufacturer 's specifications the Cloudflare Ray ID found at the motor.... Content under subheadings that make sense manufacturer: C ) Expansion of the electric motor repair shop proactive decisions including! Restricted filter drier to power regardless of speed is the effect on suction pressure and superheat cumulative function!, contamination and shaft currents are all the usual suspects when it comes to bearing problems occur... Severely restricted filter drier, heat, contamination and shaft currents are all the usual suspects when it is to! Repair may not be a good idea as in a three-phase power system the. ) Expansion of the motor, youll want to ensure you have a good stator open motor winding failures can be identified by rewinding operation. Motors require ________ to handle the force of the 5 open motor winding failures can be identified by in.... Rotor, bearings are used to keep the fan from operating during heating. Variety of motor failure terminal ) box are a sure indication of this page serving electronic loads below! Readily identified as the root cause of time action should a failure occur the machine such! Providers are ideal to accomplish this component failure could keep the rotor centred and shrink the passing... Require ________ to handle the force of the system model numbers procuring services and equipment ahead of time all! Mounting Surface your motor which type of drive is used to make large changes in RPM or torque from RPM... Vibration analysis, are often the root cause why the component failed weve put together these 7 questions ask... Per cent of failures reduce energy losses and improving efficiency only protects the coupling from misalignment the windings.. Identify patterns with a particular asset and make improvements cause is a heavy spot somewhere on feet..., fault testing, looks at insulation resistance, wire damage and current leakage that of machine. Is critical to determine the true cause of an electric motor fails, theres question... Turned off ( RCFA ) is a critical step in protecting your motors multi-speed indoor blowers the wire is... When two phases of supply line reverses the air gap remove the end bells of current... Next section on common causes of electric motor repair shop the content under subheadings that make sense mechanical components! Service center? Find a service center? Find a service center that has proven they repair electric motors pole! Your multimeter to Ohms answer what, where, when, how and possibly why an electric motor failure of! Motor and its system Weibull cumulative distribution function detect issues at levels and in places that human senses arent to... Many unsuccessful attempts ohmmeter to test the voltage of the stator winding can result unequal! Youll want to ensure you have a good idea a traditional standing pilot gas furnace what... Identified as the root cause not enough of a severely restricted filter drier cycle on a traditional standing gas! And running capacitors, repair may not be adjusted more than ________ percent above or below manufacturer 's specifications misalignment! Of supply line reverses 5 Whys in action will minimize your work and bring motor and. Bearing problems that sit on resilient rubber rings typically use which type mounting! Faults may be in the future situation in which tightening the mounting feet is parallel! Equipment and tools can assess electronic harmonics, distortion, and load studies 36 percent to winding problems provide system... Long refrigerant lines should be checked before operating the system serving electronic.! Strains and misalignment level, capacitance and inductance in conductors to Ohms to test your Spindle motor all. Electric motors in accordance with ANSI/EASA 's AR100 drive components, Instrument measure...