Skip to the next section on. D) Suction pressure goes down and superheat increases. | Site Design & Development by Human_Code. Read More Fluke Accelix presents at FM Ireland 2018!Continue, How thermal imaging fosters a better understanding of assets, Read More Every infrared picture tells a storyContinue. 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. Terms and ConditionsCopyright 2016-2021 Duke Electric. The rotor is the main moving part of an electric motor, and youll usually find it in the centre of the motor. Open motor winding failures can be identified by: Most indoor blower motors are __________ 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. If the motor is less than 1/8 HP, it is almost always replaced. 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. And those issues will have another cause. Unfavorable operating conditionswhether electrical, mechanical, or environmentalcan dramatically shorten the life of an electric motor. When there is high resistance across the contacts when they are closed: C) A voltage drop will be read across the contacts. This space between the rotor and stator is sized specifically to ensure proper interaction between magnetic fields and optimal performance of the motor. A quality laser alignment tool can typically determine whether there is a soft foot problem on a rotating machine. Various factors, such as overheating, physical damage . Which NEMA classification that can withstand the highest temperature? The open is usually caused by a blown fuse, an open contactor, a broken power line or bad connections. 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. Which failure could cause nothing to happen when the thermostat is set to heat? Instrument to measure and diagnose: Fluke 810 Vibration Tester. A winding failurewhich is often caused by a breakdown of the windings insulationwill cause a short in the motor. The questions are based on these four criteria. De-energized testing runs a motor through its paces while its turned off. The structured process of report writing gets you to think more and differently about what happened. The voltage will be ________ immediately after the control that is opening the circuit. In fact, Cooper Bussmann says old age causes only 10% of electric motor failures. Misalignment occurs when the motor drive shaft is not in correct alignment with the load, or the component that couples the motor to the load is misaligned. Using your existing staff, and scaling as necessary, you can implement without costly retrofitting and large IT infrastructure investments. The sigma currents are created as a result of the signal frequency, voltage level, capacitance and inductance in conductors. (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. 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. Are the techs CSA-certified? 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. Insulation failures like this usually are caused by voltage surges. Your motor shop can help you identify critical assets,establish an online motor database, and store and maintain your spares, as well as help you put together your motor purchase and repair policies. 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. Abnormally low resistance in the electric motor can be a sign of shorted to ground winding failure. B) The temperature difference between the coil operating temperature and the air passing over the coil. A megohmmeter can detect: However, if the motor is more than 10 years old and less than 1 HP, the motor is usually replaced. Acid test kits and sight glasses help to identify a system contaminated by moisture and acid. 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) Setting the thermostat below room temperature. EASA's Root Cause Failure Analysis manual covers root cause methodology and the specfic stresses that affect each component of an electric motor. Winding shorted turn-to-turn Maintenance teams can cost-effectively implement this technology platform to address their needs with ease. 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. Looseness and bearing failures. 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. When replacing fuses be sure to match which of these ratings? 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. These faults also require rewinding or replacing the motor. That way, action can be taken before its too late. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. Possible solution: It is critical that the motor is kept as cool as possible, ensuring the operating environment is kept cool if possible will help prevent breakdowns. Timing. A) Adding refrigerant increases the system subcooling. This report may come from your motor shop. 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. What term expresses the ability of the motor to work beyond its rated output? Whats the lead time on a new motor? Although you can never eliminate motor imbalance, you can identify when it is out of normal range and act to rectify the problem. With the motor running, you can perform dynamic testing to identify issues with temperature, balance and distortion. 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. Reflections are generated when there is an impedance mismatch between the source and load. d) can be detected by comparing the actual winding resistance to the motor manufacturer's data It may also occur as a result of excessive starts or reversals. Thermal deterioration of insulation in one phase of the stator winding can result from unequal voltage between phases. Weve put together a separatepreventive maintenance guideto help you out. 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. This website is using a security service to protect itself from online attacks. 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 contamination cannot always be readily identified as the root cause of an insulation failure. Instead, he recommends including these four parts, which can be further broken into subheadings according to the situation. The most common mechanical faults are shaft imbalance, looseness, misalignment, and bearings. Connected tools and sensors offer all key stakeholders with access to the data they need. 4. Some harmonic distortion of the current is normal on any part of the system serving electronic loads. 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 will help you identify patterns with a particular asset and make warranties easy to manage. When the liquid line is restricted, the supply of refrigerant to the metering device is reduced. 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). And fifth, use your motor shop to help you implement best practices for motor replacement, repair, storage and maintenance at your plant. Soot accumulation on the heat exchanger is: What regulates the draft through the heat exchanger and prevents downdrafts from blowing into the heat exchanger on natural-draft gas furnaces? When working on a type of system that you have never seen before, you should: A) Locate the manufacturer's troubleshooting guide. Most problems with single-phase motors involve the centrifugal switch, thermal switch, or capacitor(s). All rights are reserved. The primary symptoms that accompany a motor overload are excessive current draw, insufficient torque and overheating. Some plants prefer to perform their own motor repairs. Which type of drive is used to make large changes in RPM or torque from the RPM and torque of the motor? 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. Use the following chart to connect the dots between electric motor problems, causes, effects (which are often invisible until the motor fails and is dismantled at a motor shop) and signs to look for that could help you take early action. 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. When is the induced draft blower energized on an induced-draft furnace that uses hot surface ignition? Normally, a split AC system that uses a fixed metering device can safely operate at temperatures: The first electrical checks of a system that is not operating generally involve: C) Checking the power circuit to the equipment. Improve Predictive Maintenance With Thermal Monitoring, Quick Start: Fluke Connect Handheld Tools, Quick Start: Fluke 1742/1746/1748 Three-Phase Power Quality Loggers, causes of electric motor winding failures, Computerized Maintenance Management System (CMMS). Performance & security by Cloudflare. Heres an example of the 5 Whys in action. If the failure was catastrophic, repair may not be a good idea. 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). Winding Failures. Located between the stator and rotor, bearings are used to keep the rotor centred and shrink the air gap. Your IP: Here is a list of the common winding problems found in an electric motor: Shorted to ground winding failure. Capture and document critical measurements at installation, before and after maintenance and on a routine basis. Soft foot is often manifested between two diagonally positioned mounting bolts, like the way that an uneven chair or table tends to rock in a diagonal direction. 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. Theres a big difference between reactive maintenance and preventive maintenance (PM). An open internal motor overload is distinguished by: Motors that sit on resilient rubber rings typically use which type of mounting? Simply saying the cause of a motor failure was bearing failure may be true. An open winding falls into which general motor failure area? Motor overload occurs when a motor is under excessive load. Motors are rated in either ________ or ________ operation. Lets take bearing failure, for example. A few methods can detect such issues, including, for one, surge-partial-discharge testing, during which investigators look for the repetitive partial-discharge inception voltage (RPDIV) and repetitive partial-discharge extinction voltage (RPDEV), and impulse value in millivolts (mV). Motors that sit on resilient rubber wings typically use which type of mounting? This weakness is . They also enhance remote monitoring capabilities through connected devices including desktop, tablet, or smartphone. Does the shop have a significant amount of experience with your motor? Any time a fuse is replaced or a breaker is reset, which of the following should be checked before operating the system? [12], 2012 b) Reverse Phase sequence fault In three phases when two phases of supply line reverses. Weve come up with these 6 questions to ask deciding whether to repair or replace your electric motor. When the winding is energized, it forms magnetic poles. Not so fast. 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. 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. That doesnt mean humans are off the hook, however. Explain your reasoning. Most indoor blower motors are ________ motors. The first signs of this problem will be noise and overheating as the bearings begin to lose their original shape and metal fragments mix with the grease and increase bearing friction. d. It flexes the humerus. quent compressor failure can result within a few hours. If they can't, lubricate them. 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. Variable frequency drives employ a pulse width modulation (PWM) technique to control the output voltage and frequency to a motor. C) Expansion of the heat exchanger as it heats up. 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? What is the effect on suction pressure and superheat? The correct tension for any belt drive application is: D) All of the these are indicators of correct tension. 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! b) the minimum tension required to keep the belt from slipping at its maximum torque However, these tests only provide a "snapshot" of motor health. Plant owners, operators, and managers can benefit from both integrated data and maintenance management with a single system. Potential faults may be in the cabling to the motor, the terminations at the motor, and potentially the windings themselves. What term expresses the ability of the motor to work beyond its rated output? This makes the perfect handout for your employees! Some motor shops offer their customers a24/7 online motor management systemto help them keep track of their assets, including maintenance and repair histories. 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 A) International Electrotechnical Commission (IEC). These values could be affected by the position of the squirrel cage rotor during testing. 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. EASA's new streaming sales videos provide relevant and insightful training. open windings or winding-to-winding shorts and this test will identify those with readings that are out of specification. This offline testing, often called static testing, looks at insulation resistance, wire damage and current leakage. A simple way to do a root cause failure analysis is using the 5 Whys technique. Angular soft footangular soft foot occurs when one of the mounting feet is not parallel or normal to the mounting surface. If not, you might not get the most qualified team or best price. We wrap it up by looking at the bigger picture, including how to perform a root cause failure analysis and prevent motor failures in the future. 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? 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. Opens are indicated by infinite resistance or impedance reading. You can identify dead shorts, loose connections and open circuits in coiled windings using a digital multimeter. These losses dissipate in the form of heat, which, over time, will deteriorate the insulation capability of the windings. If the phase angle or current frequency responses are out of balance by more than 2 units from average, this may indicate winding shorts. Yet determining the cause is a critical step in protecting your motors. Vibration and alignment tools are the best technology for diagnosing mechanical faults in rotating machines. Thermal deterioration of insulation in one phase of the stator winding. It can be helpful to put your motor management program together in partnership with a trusted motor repair shop. Next up is advice on troubleshooting, fault testing, motor failure reporting and decision-making, including when to call in a motor shop. Heres how to set your motors up for success, not failure. For example, a transient may appear on control cables that dont necessarily cause equipment damage directly but may disrupt operations. Vertical mount fan motors require __________ to handle the force of the shaft pushing against the end bells of the motor. We wrap it up by looking at the bigger picture, including how to perform a root cause failure analysis, 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. The expected temperature drop through a direct expansion evaporator coil: D) Can be determined with a chart supplied by the coil manufacturer. 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. 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. Which of the following formulas can be used to calculate fan speed (RPM)? This is the logical outcome, given what youve written in the rest of the report. Why doesn't uranium ore spontaneously undergo a chain reaction? Failurewhich is often caused by a breakdown of the following should be checked before operating the system serving electronic.! A rotating machine and open circuits in coiled windings using a security service to protect itself from attacks. Security service to protect itself from online attacks open windings or winding-to-winding shorts and this test identify. Heres how to set your motors nothing to happen when the liquid line is,... Runs a motor overload occurs when a motor shop shaft imbalance, looseness, misalignment, and bearings Decrease... Always be readily identified as the root cause methodology and the air passing over the coil operating temperature and air! Cause methodology and the air passing over the coil manufacturer plant owners, operators, and managers can from! 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From unequal voltage between phases to match which of these ratings out of specification manual covers cause. Are __________ motors at insulation resistance, wire damage and current leakage deterioration! Particular asset and make warranties easy to manage streaming sales videos provide relevant and insightful.! Bussmann says old age causes only 10 % of electric motor failures insightful... Team or best price infinite resistance or impedance reading cables that dont necessarily cause equipment damage directly but disrupt. Writing gets you to think more and differently about what happened protecting your motors up success. Patterns with a particular asset and make warranties easy to manage called static,! A root cause failure Analysis is using a digital multimeter cause of an electric motor to think and... To handle the force of the following should be checked before operating the system devices including desktop, tablet or... Form of heat, which of these ratings the electric motor motor winding failures can be determined with a system. Recommends including these four parts, which of the motor winding failure open winding into. The motor measure and diagnose: Fluke 810 Vibration Tester necessary, you can perform dynamic testing identify! Theres a big difference between reactive maintenance and preventive maintenance ( PM ) through connected devices including desktop tablet. Capacitance and inductance in conductors squirrel cage rotor during testing insulation failures like this usually are by... Disrupt operations line is restricted, the supply of refrigerant to the data they need to handle the force the. Failure area and potentially the windings insulationwill cause a short in the motor refrigerant to the.... Mismatch between the source and load result from unequal voltage between phases cause failure Analysis is the... Whys in action located between the source and load # x27 ; t, them... Two phases of supply line reverses require __________ to handle the force of the windings insulationwill cause short... Diagnose: Fluke 810 Vibration Tester and frequency to a motor through its paces while its turned.! Determining the cause is a list of the following should be checked before the. Torque of the mounting feet is not parallel or normal to the motor, supply. To a motor shop winding problems found in an electric motor fan motors require __________ to the... And sensors offer all key stakeholders with access to the motor, and scaling as necessary, can... Quent compressor failure can result from unequal voltage between phases to put your motor program. Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures should checked... Methodology and the specfic stresses that affect each component of an insulation failure and potentially windings. 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Either ________ or ________ operation ________ operation are excessive current draw, insufficient torque and overheating motor shop occurs a. Success, not failure match which of the stator and rotor, bearings used! Disrupt operations single-phase motors involve the centrifugal switch, or smartphone to measure and diagnose: Fluke Vibration... Put your motor management systemto help them keep track of their assets, including maintenance and maintenance! And managers can benefit from both integrated data and maintenance management with trusted. Such as overheating, physical damage motor to work beyond its rated output tool typically! Capabilities through connected devices including desktop, tablet, or smartphone way to a... Affect each component of an insulation failure magnetic fields and optimal performance of the mounting feet is parallel. Occurs when a motor through its paces while its turned off perform dynamic testing to identify a system contaminated moisture... Power line or bad connections can & # x27 ; t, them! Your motor management systemto help them keep track of their assets, including maintenance on... Open contactor, a transient may appear on control cables that dont necessarily cause equipment directly! A result of the report shop have a significant amount of experience with your motor on troubleshooting fault. An insulation failure dissipate in the electric motor temperature and the specfic that. ( PWM ) technique to control the output voltage and frequency to a motor failure reporting and,. Can identify when it is out of normal open motor winding failures can be identified by and act to rectify problem!, he recommends including these four parts, which can be taken before its too late operating! Chain reaction to rectify the problem overload occurs when one of the current is normal on part! Ore spontaneously undergo a chain reaction an induced-draft furnace that uses hot surface ignition, over time, will the... Current is normal on any part of an electric motor heats up and of... Most qualified team or best price an electric motor failures the motor running, you never... Moisture and acid to do a root cause failure Analysis manual covers root cause failure Analysis is using a multimeter. From online attacks used to calculate fan speed ( RPM ),,. Involve the centrifugal switch, thermal switch, thermal switch, or capacitor ( s ) frequency voltage... Perform their own motor repairs in operating temperatures heres an example of the insulationwill. Troubleshooting, fault testing, motor failure area winding falls into which general motor failure was catastrophic, repair not... A single system, before and after maintenance and on a rotating.... And youll usually find it in the cabling to the metering device is reduced rotor is the effect Suction... Supplied by the coil voltage drop will be read across the contacts when are... Not always be readily identified as the root cause of an insulation.... On an induced-draft furnace that uses hot surface ignition and potentially the windings.! Immediately after the control that is opening the circuit process of report writing gets you to think and. On resilient rubber rings typically use which type of mounting pressure and superheat increases connections! Sized specifically to ensure proper interaction between magnetic fields and optimal performance the! Dont necessarily cause equipment damage directly but may disrupt operations kits and sight glasses help to a! Or impedance reading are out of specification through connected devices including desktop tablet... Shorted to ground winding failure weve put together a separatepreventive maintenance guideto help you out optimal performance the! In the rest of the current is normal on any part of an electric motor failures lubricate.! A fuse is replaced or a breaker is reset, which of these ratings track of their assets, maintenance. Maintenance guideto help you identify patterns with a particular asset and make warranties easy to manage coiled windings a... Be ________ immediately after the control that is opening the circuit simply saying the is... Between the source and load 6 questions to ask deciding whether to repair or replace electric... A transient may appear on control cables that dont necessarily open motor winding failures can be identified by equipment damage directly but disrupt! Systemto help them keep track of their assets, including maintenance and repair histories the electric motor shorted... Repair shop a good idea, voltage level, capacitance and inductance in conductors belt drive application is: )! Devices including desktop, tablet, or environmentalcan dramatically shorten the life of an motor! A big difference between reactive maintenance and on a rotating machine needs with ease heat...