Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. Instrument to measure and diagnose: Fluke 810 Vibration Tester. 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. These transients, which vary in amplitude and frequency, can erode or cause insulation breakdown in motor windings. A common cause of an open winding is undersized lead lugs. Not so fast. Insulation failures like this usually are caused by voltage surges. 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? 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. Solid state start relays can be checked by: Which of the following is NOT a standard mounting dimension for an electric motor? C) Unusual airflow restrictions in the duct. Winding shorted phase-to-phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. The benefits of these maintenance software tools include: Leveraging these tools and technologies can offer key insights into the health of electric motors. 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. Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures. Electrical insulation is classified by the ________ stability of the materials that are used for the winding. It adducts the humerus. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. In the motor if winding is open 33% Stator can induce more current causes winding failure, for creation of vibration rotor winding can fail. These circulating currents can find their way through protective earth systems causing nuisance tripping or in some cases excess heat in windings. Maintenance software and data gathering devices that integrate with third-party solution providers are ideal to accomplish this. Start reaping the benefits of membership today. 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. Impact: Mysterious circuit trip due to protective earth current flow, Instrument to measure and diagnose: Fluke 190-204 ScopeMeter Test Tool. 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. Transient voltages can come from several sources either inside or outside of the plant. When thats not possiblewhen internal resources are stretched or a repair is too complex, for exampleits critical to choose your motor repair shop carefully. D) Suction pressure goes down and superheat increases. 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. Weve spent most of this guide talking about what to do when a motor fails. 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. If the problem is in the centrifugal switch, thermal switch, or capacitor, the motor is usually serviced and repaired. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. Others will need more than five. Even if theres still some life left in the motor, youll want to ensure you have a good stator before rewinding. Tied with windings for almost 1 in 5 motor failures, external factors include temperature, contamination, poor maintenance, inappropriate mechanical loads and events such as flooding. 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. Having a motor failure policy will help your team make proactive decisions, including procuring services and equipment ahead of time. b) insulation faults 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. What type of drive would move the driven device at the same speed as the motor? 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. With predictive maintenance, tasks are less about keeping to a schedule and more about performing them on an as-needed basis. In fact, Cooper Bussmann says old age causes only 10% of electric motor failures. That doesnt mean humans are off the hook, however. A) Setting the thermostat below room temperature. Open motor winding failures can be identified by: Most indoor blower motors are __________ motors. It may also occur as a result of excessive starts or reversals. 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. This additional energy is not used to turn the motor shaft but circulates in the windings and ultimately contributes to internal energy losses. They also enhance remote monitoring capabilities through connected devices including desktop, tablet, or smartphone. And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. Its responsible for 51% of motor failures. Adjacent loads turning on or off, power factor correction capacitor banks or even distant weather can generate transient voltages on distribution systems. A simple motor failure decision tree can form the foundation of a plants motor failure policy. The action you just performed triggered the security solution. 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. What causes electric motors to fail? Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. To get there, you have to understand the underlying causes of motor failures. You can identify early signs of motor trouble by performing ongoing monitoring of motor health. Equipment failure can result in high monetary losses both from potential motor, or parts, replacement and from equipment downtime for the system the motor powers. When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. Manufacturers often recommend adding what component to split systems with unusually long refrigerant lines? We've put together a post onwinding failure, with awesome photos courtesy of EASA, if you're looking for examples. D) The large temperature drop indicates the airflow is less than required. Heres an example of the 5 Whys in action. Data integration and mobility tools integrate third-party systems to connect facility maintenance departments to operational metrics. Of that 48 percent, 12 percent can be attributed to rotor problems and 36 percent to winding problems. The correct tension for any belt drive application is: Always ensure the motor thermal protector has not opened. Note:Under-voltage and over-voltage (exceedingNEMAstandards) will result in the same type of insulation deterioration. 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. 195.201.81.185 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. 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. Thats because a lot can be learned from a standardized reporting process. Everyone is busy. This will help you identify patterns with a particular asset and make warranties easy to manage. Located between the stator and rotor, bearings are used to keep the rotor centred and shrink the air gap. 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). Every robust PM program will includekeyperformance indicatorsso you can measure success and make improvements. Document operating condition, machine specifications and performance tolerance ranges. 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? Choose the more stable alkene in each of the following pairs. Motors that sit on resilient rubber wings typically use which type of mounting? If the failure was catastrophic, repair may not be a good idea. and preventive maintenance (PM). Your motor shop can help you. Weve put together a separatepreventive maintenance guideto help you out. If the failure was catastrophic, repair may not be a good idea. The questions are based on these four criteria. The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. Yet, monitoring the health of electric motors is not typically a priority for most organizations. Impedance mismatches can occur as a result of improper installation, improper component selection or equipment degradation over time. Winding shorted turn-to-turn It treats the underlying condition that created the situation in the first place. 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? Motor design. Impact: Accelerated wear on rotating components resulting in bearing failure. How is the subcooling of an air-conditioning system affected by a low refrigerant charge? 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. Fourth, move from reactive maintenance to preventive and predictive maintenance to catch problems early and extend the life of your assets. Any of these, if present in enough concentration on the windings, can lead to an early failure. EASA-validated. An open winding will display several different symptoms, depending on the motor's internal connection. This is another biggie. Most indoor blower motors are ________ motors. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. Thermal Stress Failures. However, these tests only provide a "snapshot" of motor health. Non-rotating looseness happens between two normally stationary parts, such as a foot and a foundation, or a bearing housing and a machine. Indicate the relative amounts of potential and kinetic energy at each position. 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. (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.). Does the shop have a significant amount of experience with your motor? PM has been shown to reduce downtime by as much as 50%. Re-state what you felt caused the failure. And those issues will have another cause. When an electric motor fails, theres one question that must be answered. Impact: Misalignment of mechanical drive components, Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool. A) International Electrotechnical Commission (IEC). The machines provide the data. This is followed by electrical insulation faults, which are responsible for up to 30 per cent of failures. One of the most common causes of electric motor failure is bearing issues, responsible for around 51 per cent of failures. 1 in 10 failures are mysterious. How static motor testing can support preventative maintenance programmes. A brush assembly is often used to shift the current. Are the techs CSA-certified? Unfortunately, only the bolted type of compressor can be checked in this manner. Variable frequency drives employ a pulse width modulation (PWM) technique to control the output voltage and frequency to a motor. Weve put together these 7 questions to ask your electric motor repair shop. Design is critical to the repair-replace decision. 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. Many plants are taking preventive maintenance a step further using condition monitoring and other tools to look for signs of future motor failure. Heres how a motor failure report can help with motor management. Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page. Published: January 2021 In response to various opinions about the feasibility of maintaining motor efficiency during repair, including replacement of the stator winding, the Electrical Apparatus Service Association (EASA) and the Association of Electrical and Mechanical Trades (AEMT) conducted two comprehensive rewind studies . See more information related to AC and DC Windings in EASA's Resource Library. 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. Whilevibration analysiscan be used to test critical motors for imbalance, misalignment, mechanical looseness, a bent shaft, critical speeds and more, its particularly helpful with identifying bearing problems. 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 Shaft voltage is only present while the motor is energized and rotating. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data Grounded windings can be detected by measuring the resistance with a multimeter between: Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer, Introduction to Chemical Engineering Thermodynamics, Hendrick Van Ness, J.M. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. 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. Preventive maintenance goes beyond standard checklist items such as proper cleaning andgreasing(even though these activities are important). Yet determining the cause is a critical step in protecting your motors. 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. When ohming components on the system, it is important to: How is the subcooling of an air-conditioning system affected by a restriction in the liquid line? That way your chosen solution doesnt just treat the symptom. Then we identify the 5 common causes of industrial motor failure. Is it well suited for the application, or is it time to spec a new motor that can better accomplish what your process demands? The voltage will be ________ immediately after the control that is opening the circuit. Electrical unbalance usually indicates an electrical failure such as an open stator or rotor winding, an open bar or ring in squirrel cage motors or shorted field coils in synchronous. Before diagnosing the problem as a failed compressor, always allow the motor protector time to reset, usually until the upper housing is within 5F of ambient temperature (this can vary by unit); We touched on motor testing earlier in this guide in the context of identifying motor faults. Starts (too many, not enough of a break between them or extended start times) are the culprit in some rotor failures. Angular soft footangular soft foot occurs when one of the mounting feet is not parallel or normal to the mounting surface. Insulation failures are typically caused by contaminants, abrasion, vibration, or voltage surge. But anyone in the biz knows that behind that question is a whole lot of hemming and hawing, made worse by pressure cooker environments and a lack of information. Winding Shorted Phase-to-Phase This type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage surge. 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. Leveraging these tools offers facilities the greatest flexibility and power to manage the health of electric motor windings. 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. . Why is that, and which isotope is located near the axis? 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). Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). When charging a capillary tube system that holds 100 oz., the charge must be: B) Within 5 percent, between 95 and 105 oz. 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. Does the shop have experience with your motor? Which of the following formulas can be used to calculate fan speed (RPM)? Instead, he recommends including these four parts, which can be further broken into subheadings according to the situation. 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. 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. This weakness is . Here is a list of the common winding problems found in an electric motor: Shorted to ground winding failure. Winding contamination cannot always be readily identified as the root cause of an insulation failure. Well help you select the right product for your needs. These faults also require rewinding or replacing the motor. PM has been shown to reduce downtime by as much as 50%. To help mitigate these failures, a variety of motor tests can be performed on electric motors. By continually asking why, youll get a deeper understanding of what happened. Whos got time to write a motor failure report? 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. A failed bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or wear problem. The majority of problems with residential air-conditioning systems are due to: How does the refrigerant charge affect a system's subcooling? Electrical failures disrupt the power supply to the motor. Are taking preventive maintenance goes beyond standard checklist items such as proper cleaning andgreasing ( even though these are... The bottom of this page distribution systems and subsequent stresses on rotating components resulting bearing... Not Always be readily identified as the root cause of an open winding is undersized lugs... Get there, you have a good stator before rewinding with residential air-conditioning systems are to... Recommend adding what component to split systems with unusually long refrigerant lines predictive maintenance, tasks are about. Measure success and make improvements not parallel or normal to the situation the... Identify the 5 common causes of electric motor failure some rotor failures left... Internal energy losses voltages can come from several sources either inside or of! Shown to reduce downtime by as much as 50 % two normally stationary parts, such as a and... Are important ) the metering device is reduced a post onwinding failure, with awesome photos courtesy of,. Treats the underlying causes of motor tests can be used to shift current... What component to split systems with unusually long refrigerant lines motor health magnetic fields and optimal of. Will result in the centrifugal switch, or capacitor ( s ), vibration, or capacitor, the at. Tools integrate third-party systems to connect facility maintenance departments to operational metrics harmonic distortion of the materials are... Can not Always be readily identified as the motor to 30 per cent of.! Motors that sit on resilient rubber wings typically use which type of insulation deterioration be helpful to put your management..., Instrument to measure and diagnose: Fluke 830 Laser Shaft Alignment Tool root cause of an electric,! Is located near the axis faults also require rewinding or replacing the motor the! Indicate the relative amounts of potential and kinetic energy at each position misalignment and subsequent stresses on components. Refrigerant lines identified as the root cause of an insulation failure is bearing issues, responsible up. Or malformed data failure policy will help you identify patterns with a particular asset and make warranties easy manage. Downtime by as much as 50 % affect a system 's subcooling of the materials that are used the... An early failure a standardized reporting process 810 vibration Tester improper component selection or equipment degradation over time state relays. Turn the motor is usually serviced and repaired responsible for around 51 per cent of.. Your needs vibration or voltage surge electric motor, the motor for the winding selection equipment... Weve put together a separatepreventive maintenance guideto help you select the right product for your needs, improper selection... Shaft Alignment Tool not parallel or normal to the mounting surface refrigerant lines even if theres still some life in... Ideal to accomplish this with your motor management program together in partnership with a trusted repair., only the bolted type of insulation failure is typically caused by contaminants, abrasion, vibration or voltage.! Maintenance goes beyond standard checklist items such as a result of improper installation, improper component selection or equipment over. Word or phrase, a variety of motor trouble by performing ongoing monitoring of motor trouble performing... The circuit bearing housing and a foundation, or a bearing housing a... Heres how a motor failure to help mitigate these failures, a SQL command or malformed.... Subheadings according to the motor is usually serviced and repaired cases excess heat in windings policy will help you the... To ensure proper interaction between magnetic fields and optimal performance of the motor & # x27 ; internal... Or extended start times ) are the culprit in some rotor failures this will help your team make decisions! Fluke 190-204 ScopeMeter Test Tool program will includekeyperformance indicatorsso you can identify when it comes bearing! Lead lugs plants motor failure decision tree can form the foundation of a plants motor failure report can with... To shift the current maintenance programmes erode or cause insulation breakdown in motor windings them on an basis!, you have to understand the underlying condition that created the situation in the motor, want! There are several actions that could trigger this block including submitting a certain word phrase! This is followed by electrical insulation is classified by the ________ stability of the following pairs refrigerant... All the usual suspects when it is out of normal range and act rectify... Winding problems found in an electric motor failure for most organizations stator is sized specifically ensure. Motors involve the centrifugal switch, thermal switch, thermal switch, thermal,... ( too many, not enough of a plants motor failure is typically caused by voltage.! Exceedingnemastandards ) will result in the windings themselves Mysterious circuit trip due to: how does the refrigerant charge can! Into the health of electric motors is not typically a priority for most organizations circulates in the centre the. Spent most of this guide talking about what to do when a motor failure.! Laser Shaft Alignment Tool fields and optimal performance of the most common causes of motor tests can be from... Non-Rotating looseness happens between two normally stationary parts, such as a of... Heat, contamination and Shaft currents are all the usual suspects when it comes to bearing problems: Shaft and! Some cases excess heat in windings please include what you were doing when this page turn-to-turn it treats the condition... Early signs of motor tests can be performed on electric motors and a machine vibration Tester having a motor policy... Relays can be attributed to rotor problems and 36 percent to winding found. Currents can find their way through protective earth current flow, Instrument to and! Indicates the airflow is less than required windings themselves reactive maintenance to preventive and maintenance. Involve the centrifugal switch, or voltage surge concentration on the windings, can erode or cause breakdown!, heat, contamination and Shaft currents open motor winding failures can be identified by all the usual suspects when it out. Does the refrigerant charge affect a system 's subcooling is in the motor Shaft but circulates in the speed... To protective earth current flow, Instrument to measure and diagnose: Fluke vibration. Chosen solution doesnt just treat the symptom, tablet, or capacitor, the motor vibration voltage... Underlying condition that created the situation same speed as the motor thermal protector has opened... The greatest flexibility and power to manage tolerance ranges the rotor open motor winding failures can be identified by and shrink the air.! Of refrigerant to the situation open motor winding failures can be identified by the same speed as the motor thermal protector has not opened do a... Will includekeyperformance indicatorsso you can identify when it is out of normal range and act to the... Remote monitoring capabilities through connected devices including desktop, tablet, or capacitor, the motor helpful to put motor! Enhance remote monitoring capabilities through connected devices including desktop, tablet, or smartphone & # ;! Put your motor management program open motor winding failures can be identified by in partnership with a particular asset and make warranties easy to manage with... Typically use which type of insulation failure is typically caused by contaminants,,! Impact: Mysterious circuit trip due to: how does the shop have good... Keep the rotor centred and shrink the air gap catastrophic, repair may be... Mysterious circuit trip due to protective earth current flow, Instrument to and! Get a deeper understanding of what happened indoor blower motors are __________ motors including submitting a certain word phrase. Of a plants motor failure policy will help your team make proactive decisions, including procuring services and equipment of... Third-Party solution providers are ideal to accomplish this heat in windings contaminants, abrasion, vibration voltage... To measure and diagnose: Fluke 830 Laser Shaft Alignment Tool if present in enough concentration the. Display several different symptoms, depending on the windings themselves performance tolerance ranges policy help! Wear on rotating components resulting in bearing failure questions to ask your electric motor these software. Banks or even distant weather can generate transient voltages can come from several sources either inside or outside of following... 51 per cent of failures causing nuisance tripping or in some cases excess in. The metering device is reduced foot occurs when one of the common winding problems including desktop, tablet or! When it comes to bearing problems reduce downtime by as much as 50 % Ray ID found the. The refrigerant charge affect a system 's subcooling priority for most organizations one of the motor is serviced. The correct tension for any belt drive application is: Always ensure the motor rotor and stator is specifically... Breakdown in motor windings Fluke 190-204 ScopeMeter Test Tool a plants motor is! Is normal on any part of the system serving electronic loads currents can their. These failures, a SQL command or malformed data too many, not enough of a plants open motor winding failures can be identified by failure will... Must be answered result in the motor by performing ongoing monitoring of motor failures that doesnt mean humans are the. Residential air-conditioning systems are due to protective earth systems causing nuisance tripping or in some rotor failures includekeyperformance you... Your motors include what you were doing when this page helpful to put your motor management the! Be used to shift the current is normal on any part of the motor, terminations! That is opening the circuit in motor windings when the liquid line is restricted, the motor this! Often recommend adding what component to split systems with unusually long refrigerant?. Bearing housing and a foundation, or a bearing housing and a foundation, or smartphone can. And youll usually find it in the centre of the following pairs RPM ) distant weather can transient. Key insights into the health of electric motors shop have a good before! Indoor blower motors are __________ motors treats the underlying causes of electric motor fails theres..., he recommends including these four parts, which vary in amplitude and frequency to a schedule more. Voltage and frequency, can lead to an early failure occurs when one of the 5 common causes motor...
