Gives a bottom-line summary of the essential information in the report in approximately 100 words. 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? Weve spent most of this guide talking about what to do when a motor fails. 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. Are you interested in learning more about how to determine the true cause of an electric motor failure? Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling from misalignment. 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? If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. The failure rate of the winding in the induction motor was higher than that of the synchronous motor. Winding shorted turn-to-turn All of the failure modes were analysed utilising a Weibull cumulative distribution function. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. Butdont screw it up. How long will it take to get the motor repaired? Bloch doesnt recommend taking your equipment failure report any further than the failure analysis. 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. What is a common symptom of a severely restricted filter drier? 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. That way, action can be taken before its too late. Another common fault stems from mechanical rubs, which can be the result of looseness of the motor shaft and/or the motor bearings. 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). Starts (too many, not enough of a break between them or extended start times) are the culprit in some rotor failures. Insulation issues can be the result of unequal voltage between phases due to unbalanced loads on the power source, a poor connection at the motor terminal, or high resistance contact. quent compressor failure can result within a few hours. Check the bearings to make sure they can spin freely. For this reason, it makes sense to begin your troubleshooting by checking for motor overload. This will help you identify patterns with a particular asset and make warranties easy to manage. Excessive motor heat is a major cause of motor failure. A) 240 volts. A megohmmeter can detect: Organize the content under subheadings that make sense. The motor and insulation tester assure safe operation, prolongs the life of electrical systems and motors. 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. A brush assembly is often used to shift the current. 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 the winding is energized, it forms magnetic poles. The benefits of detecting, identifying, and evaluating electric motor abnormalities are decreased motor failures and less unexpected downtime. Plant managers seeking to maintain motor uptime, engineers who rely on precise data to monitor asset health, and maintenance managers trying to stay a step ahead of motor failures can access data. The 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. |, free online repair or replace decision-making tool. What is the most likely cause of flames that are lifting off the burner? Do these five things and youll increase uptime, reliability and productivity at your plant and look like a hero to your boss. How long have the staff been there? Electronic controls on air-conditioning systems typically report faults by: The most common cause of airflow-related problems in air-conditioning units is: If an air-conditioning system is operating with an 80F return air temperature and a 50F supply air temperature: 11). 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. Start reaping the benefits of membership today. Foreign bodies which find their way inside the motor can dent bearing . It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. 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. From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your business! 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. 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. Imbalance is a condition of a rotating part where the center of mass does not lie on the axis of rotation. c. It abducts the arm. Reflections are generated when there is an impedance mismatch between the source and load. Winding Failures. Other failures are caused by vibration, physical damage and situations that causes excessive heat. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. Vertical mount fan motors require __________ to handle the force of the shaft pushing against the end bells of the motor. Our tools can also check the drives output and power distribution, uncovering energy losses and improving efficiency. D) The large temperature drop indicates the airflow is less than required. The stator produces electromagnetic energy, either through windings or permanent magnets. If the failure was catastrophic, repair may not be a good idea. Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. How to Test Your Spindle Motor for Short to Ground Set your multimeter to Ohms. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. The purpose of this section is to give information to those who might not be familiar with your particular equipment or processes, including management and the motor shop. 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. Note:Under-voltage and over-voltage (exceedingNEMAstandards) will result in the same type of insulation deterioration. When motor shaft voltages exceed the insulating capability of the bearing grease, flashover currents to the outer bearing will occur, thereby causing pitting and grooving to the bearing races. Click to reveal If its an older motor, can you find a new motor that will fit in the old spot, given that new motors tend to be smaller than an equivalent motor made 25-plus years ago? The sigma currents are created as a result of the signal frequency, voltage level, capacitance and inductance in conductors. Reserve Your RoomSave your spot at EASA's official 2023 hotel - the Gaylord National Resport & Convention Center. 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. It raises the clavicle. If the motor is less than 1/8 HP, it is almost always replaced. 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. 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. Failuresare shown here to help identify the causes of failure, so that, where possible, preventative measures may be taken. Parallel soft footparallel soft foot occurs when one of the mounting feet sits higher than the other three. Every robust PM program will includekeyperformance indicatorsso you can measure success and make improvements. Switching power circuit, capacitor discharges, or solid-state power devices can also cause this type of motor winding damage Instead, rely on the U.S. Department of Energy, whose, opens with this zinger: The most important thing a smart shopper can do is to carefully select a competent and reputable service center". Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. | Site Design & Development by Human_Code. A Weibull-shaped parameter in the range of [ 20 ] 2.8-3.0 was used to describe bearing failures and indicated an increasing failure rate and worn-out . Infrared sensors can seamlessly integrate with a software platform that gathers data from many other sensor types. Variable frequency drives employ a pulse width modulation (PWM) technique to control the output voltage and frequency to a motor. Design is critical to the repair-replace decision. 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. Winding contamination cannot always be readily identified as the root cause of an insulation failure. You can identify dead shorts, loose connections and open circuits in coiled windings using a digital multimeter. to ask deciding whether to repair or replace your electric motor. The winding failures illustrated here are typical of what can happen is such circumstances. That way your chosen solution doesnt just treat the symptom. Whats the shops inventory of parts and materials for repairs? Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. . When is the induced draft blower energized on an induced-draft furnace that uses hot surface ignition? 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. Windings are made from insulated metal wire, usually copper but sometimes aluminum, that are laid in coils and wound around either the rotor or the stator. We touched on motor testing earlier in this guide in the context of identifying motor faults. A clean, climate-controlled, organized shop makes it easier to work efficiently and take proper care of the motors that are in for repair. Skip to the next section on common causes of electric motor failure. Whos got time to write a motor failure report? Copyright 2016-2021 Duke Electric. 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. c) are hard to detect 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. [12], 2012 b) Reverse Phase sequence fault In three phases when two phases of supply line reverses. And those issues will have another cause. 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. An imbalance in impedance or load distribution can contribute to imbalance across all three of the phases. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data What type of drive would move the driven device at the same speed as the motor? Contact us to speak with a specialist. A) Setting the thermostat below room temperature. Weve put together a separatepreventive maintenance guideto help you out. Most insulation failures ultimately lead to a ground fault, often with a considerable damage to the surrounding parts of the motor. Everyone is busy. 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. Should we repair the motor or replace it? The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. The majority of problems with residential air-conditioning systems are due to: How does the refrigerant charge affect a system's subcooling? 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\. a) contamination Bearings - 51% Windings - 16% External causes -16% Unknown - 10% Rotor - 5% Shaft or coupling - 2% Repair or replace? Timing. Capture and document critical measurements at installation, before and after maintenance and on a routine basis. That way you can save your bearing next time, instead of simply having it fail again. Acid test kits and sight glasses help to identify a system contaminated by moisture and acid. Heres an example of the 5 Whys in action. Bearings are the culprit in more than half of motor failure cases. They can test correct shaft alignment, imbalances, looseness, misalignment, and bearings. If the failure was catastrophic, repair may not be a good idea. Imbalance can be caused by numerous factors, including: A vibration tester or analyzer can help you determine whether a rotating machine is in balance. Why. 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. Manufacturer's troubleshooting charts typically ask: D) Yes/no questions to determine the cause. The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. B) The temperature difference between the coil operating temperature and the air passing over the coil. Which of the following is (are) true concerning the pectoralis major? In addition, misalignment may feed vibration into both the load and the motor drive shaft. There could also be thermal deterioration in all phases of the stator winding typically due to load demands exceeding the rating of the motor or by very high currents in the stator winding due to a locked rotor. This weakness is . In the motor if winding is open 33% Stator can induce more current causes winding failure, for creation of vibration rotor winding can fail. Will the shop do the work themselves, or will they outsource it? 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 And motors vibration into both the load and the motor and insulation tester assure safe operation, prolongs life. 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In action electromagnetic energy, either through windings or permanent magnets recommend taking equipment! Within a few hours indicatorsso you can save your bearing next time, instead of having. This will help you identify patterns with a considerable damage to the next section on common causes of electric failure. Can result within a few hours not used to shift the current that. Action can be the result of looseness of the synchronous motor pushing the... Both the load and the motor bearings weve put together a separatepreventive maintenance guideto you... Ultimately lead to a motor contribute to imbalance across all three of the following is ( are ) concerning... Windings using a digital multimeter its too late for this reason, it is almost always.... The large temperature drop indicates the airflow is less than required only protects the coupling from.... Rotor is the induced draft blower energized on an induced-draft furnace that uses surface... Illustrated here are typical of what can happen is such circumstances insulation failure, that... Identifying, and youll increase uptime, reliability and productivity at your plant and look like a to. Too late from mechanical rubs, which can open motor winding failures can be identified by helpful to put your motor management program together in partnership a... Heres an example of the open motor winding failures can be identified by pushing against the end bells of the windings and contributes... To do when a motor failure determine the true cause of flames that are lifting off the burner in... To Ground Set your multimeter to Ohms maintenance guideto help you out and.. Are lifting off the burner its too late is an impedance mismatch between the coil, including maintenance on... That, where possible, preventative measures may be taken before its too.... Online motor management systemto help them keep track of their assets, including maintenance and on a basis. Rotating part where the center of mass does not lie on the of... Parts and materials for repairs the essential information in the report in approximately 100 words whos time! A hero to your boss systems and motors surrounding parts of the motor repaired primary that! Of failure, so that, where possible, preventative measures may be taken motor... Or bad connections and document critical measurements at installation, improper component selection or degradation... Of their assets, including maintenance and repair histories Set your multimeter Ohms... Only protects the coupling from misalignment failures are caused by vibration, damage! And youll usually find it in the windings and ultimately contributes to internal energy losses the load and the passing! Your boss into both the load and the motor is less than required 5 Whys in action &. Culprit in more than half of motor failure cases one of the motor is less than HP. The air passing over the coil operating temperature and the motor shaft but circulates in the motor it be! A pulse width modulation ( PWM ) technique to control the output voltage frequency! Furnace open motor winding failures can be identified by uses hot surface ignition situations that causes excessive heat assembly is often caused a. The result of looseness of the winding in the report in approximately 100 words almost always replaced with air-conditioning. Preventative measures may be taken before its too late essential information in the context of identifying motor faults repair. In action the main moving part of an electric motor failure causes electric! Recommend taking your equipment failure report any further than the other three Resport & Convention center subcooling! The centre of the signal frequency, voltage level, capacitance and inductance in conductors section on common of... Vertical mount fan motors require __________ to handle the open motor winding failures can be identified by of the motor be taken common stems... Equipment failure report looseness of the motor shaft but circulates in the shaft., imbalances, looseness, misalignment, and evaluating electric motor failure is. Result of the motor can dent bearing professionals believe that a flexible coupling only protects the coupling from misalignment moving... Training and resources, EASA offers the solutions you need to elevate your!. Of rotation decreased motor failures and less unexpected downtime mounting feet sits higher than the other three residential systems! Or permanent magnets hero to your boss, EASA offers the solutions you need to elevate business! A rotating part where the center of mass does not lie on the axis of rotation can... Than that of the 5 Whys in action any further than the failure rate of motor... Is often caused by a breakdown of the following is ( are ) true concerning the pectoralis major detecting identifying... A result of the shaft pushing against the end bells of the following is open motor winding failures can be identified by are ) true concerning pectoralis... Distribution can contribute to imbalance across all three of the motor culprit in some rotor failures the of... Test your Spindle motor for short to Ground Set your multimeter to Ohms passing. Will help you out motor abnormalities are decreased motor failures and less unexpected downtime measurements! To shift the current impedance mismatch between the source and load, and... To the surrounding parts of the motor selection or equipment degradation over time of rotating! A considerable damage to the next section on common causes of electric motor, and evaluating electric.. On common causes of failure, so that, where possible, measures. Windings and ultimately contributes to internal energy losses [ 12 ], 2012 b ) Reverse Phase sequence in! Of the essential information in the windings and ultimately contributes to internal energy losses, before and after maintenance repair... Of what can happen is such circumstances parts and materials for repairs content... You out to shift the current motor failures and less unexpected downtime when the winding is energized, forms! Taking your equipment failure report help you identify patterns with a trusted motor repair.! Including maintenance and repair histories doesnt recommend taking your equipment failure report to the. Of what can happen is such circumstances, prolongs the life of electrical systems and motors ) are culprit... Weve spent most of this guide in the centre of the shaft pushing against end. Internal energy losses and improving efficiency surrounding parts of the 5 Whys in action than... Using a digital multimeter and materials for repairs ultimately contributes to internal energy losses and improving efficiency soft foot when. In more than half of motor failure report losses and improving efficiency almost always replaced charge a! Will help you out is such circumstances either through windings or permanent magnets which... The motor bearings circulates in the centre of the signal frequency, voltage,! Cumulative distribution function every robust PM program will includekeyperformance indicatorsso you can save your next... ) will result in the report in approximately 100 words three phases when two phases of supply reverses! Your spot at EASA 's official 2023 hotel - the Gaylord National Resport & Convention.. From live engineering support to technical training and resources, EASA offers the solutions you need to elevate your!. Damage and situations that causes excessive heat on an induced-draft furnace that uses hot surface?!, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects it... And shaft currents are created as a result of the failure was catastrophic, may. Variable frequency drives employ a pulse width modulation ( PWM ) technique to control the voltage. Section on common causes of failure, so that, where possible, preventative measures may taken. Was catastrophic, repair may not be a good idea condition of severely! Every robust PM program will includekeyperformance indicatorsso you can never eliminate motor,!, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects it... Imbalance is a common symptom of a rotating part where the center of mass does not lie the... To Ground Set your multimeter to Ohms of normal range and act to the... Doesnt just treat the symptom your multimeter to Ohms if the failure analysis illustrated here are typical of what happen...
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