3 phase motor troubleshooting pdf

6. To establish that there is enough capacity to power the motor and drive system. Phase B Phase C. Fig 7: 3 phase motor. Insulation – resistance tests on insulated bearings. OPERATION & MAINTENANCE MANUAL FOR THREE PHASE INDUCTION MOTORS TECO-Westinghouse Motor Company 5100 North IH-35 Round Rock, Tx. . Voltage should be within plus or minus 10 percent of nominal. Therefore, motor troubleshooting involves the entire system, not just the motor. If your voltage measurements are within an acceptable range and the circuit appears to be correctly configured but there are still problems such as the motor drive resetting or circuit breakers opening, there may be intermittent power supply problems. Frequency should be within 0.5 Hz of nominal. Many simple "across the line" single-phase and 3-phase motors (used in household appliances and industry respectively) can be checked simply by changing the range of the ohm meter to the lowest offered (R X 1), zeroing the meter again, and measuring the resistance between the leads of the motor. By checking the supply voltage, current, and frequency first, you can rule out issues that might affect the motor drive or breaker circuits. Tools, Reference Materials, Resources and Basic Information for Learning Electrical Engineering. 1) Check The Connection Of Motor. 78681 3) Reduced The Motor … 4. So, if the measured current is 30 amps, 35 amps and 30 amps, the average is 31.7 amps, and the current unbalance is. First discharge the capacitor. Induction motor doesn’t revolve, why and how to do? (Nominal values are expected values - for example, 480 volts for a 480-volt line, the current listed on motor's nameplate, and a frequency of 50 or 60 Hz, depending on your locale). Be sure such technicians observe standard safety precautions including those in this Troubleshooting … 3. OPERATION & MAINTENANCE MANUAL FOR THREE PHASE INDUCTION MOTORS 5100 North IH-35 Round Rock, Tx. Correcting current unbalance helps prevent overheating and the deterioration of motor-winding insulation. Many people associate transients with external events, such as lightning surges, but transients can also originate within a system or building. This is also true for current measurements. Measuring three phases at the same time can also reveal interactions between the phases that can't be seen with single-phase measurements. Testing and inspection of surge protection devices. The motor is being cycled too frequently. Because voltage or current unbalance can cause downtime or damage to a motor drive, learning how to interpret these measurements is important (Figure 6). Visit our contact us page for repairs, technical support and other questions. In this case, consult the wiring diagram of the motor to be sure that the meter is … The basic steps in ascertaining the health of a three-phase AC motor are given below: See how to measure insulation resistance of Electric Motor, How To Test and Check Single phase Electric Motors, How to Test a 3 Phase Motor Windings With an Ohmmeter, How to Calculate Inverter Power Rating and Inverter Battery Backup Time, How to Measure Electric Motor Insulation Resistance, Types of Earthing Systems Used in Electrical Installations, Resistance and Reactance per km of Copper and Aluminium cables, How to Install and Wire a Photocell Switch in a Lighting Installation. High neutral current can indicate unbalance. In general, "nominal" means "named." These other frequencies, which are multiples of the fundamental (so 120 Hz, 180 Hz, and so on for a 60 Hz fundamental frequency), are called harmonics. These motors run conveyor belts, pumps, fans, and many other applications. Ensure … (480v + 485v + 490v) / 3 = 485 average voltage, (5 v maximum deviation from average * 100) / (485 v average) = 1 percent voltage unbalance. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. ], McGraw-Hill Companies, 2011 Current should never exceed the nameplate rating of the load. Any value greater 0.5 ohms indicate trouble with the motor. . This application note maps common problems to the measurements used to diagnose them . There are three reasons to make input measurements: You should start your diagnostic efforts at the input side of the motor drive because the voltage, current, and frequency of the electricity that powers a variable speed motor system can affect its operation in the short term and its longevity and reliability over the long term. We show you what tools to use for a given situation and how to apply them to a problem, to enable you to troubleshoot more quickly and accurately. The amount of deviation from nominal that is considered acceptable varies by locale, but as a rule: Ideally, the voltages that you measure in each phase of a three-phase system should be the same. If the voltage is consistently too high, consult with the electric utility (. In a perfect world, the fundamental frequency is the only one present. Tips For Troubleshooting Electric Motors Understanding the nuances of various motor types is essential when servicing or installing such units B Y D E N N I S B U S H A fter more than 100 years of use, with an ever increasing installed base, there are probably few aspects of an electric motor's usage and failure modes that have not been documented. 3 phase induction motor have 3 winding; assume U, V and W. Every winding has its own resistance. This motor benefits from the experience of one of the largest manufacturers in the world, using state-of-the-art technology in automation, specially selected materials and rigorous quality control. Inside your facility, however, harmonics may be high if there are a lot of harmonic-generating devices in the facility. Category: Power Tags: 3 phase motor troubleshooting pdf, 3 phase motor winding resistance values, 3 phase testing procedure, how to test a 3 phase motor with a megger, how to test motor windings single phase, motor insulation resistance test procedure, motor megger test results, types of motor … Further troubleshooting maybe required Power Supply Test For three phase motors, the expected voltage for a 230/400V system is 230V phase to neutral and 400V between each of the three phase supply lines. If all voltage, current, and frequency measurements are within an acceptable range, check for voltage and current unbalance. A.3 Three-phase Zero Crossing Time Calculation (zcrinterp3phase.m) . Do this by comparing your current measurements with the circuit breaker rating. To get the percentage of unbalance, divide the biggest deviation measured on one phase by the average of three phases and multiply by 100. Test Results of Stator Short Faults before Misalignment Adjust 95 Appendix C. Test Results of Stator Short Faults after Misalignment Adjust 111 Second, the drive and its output, where the ac to dc converter, the dc filter, and the dc to ac inverter provide the three phase power to the motor. So let’s take it one by one: Here we are giving you only overview on 3 phases induction motor. So, the nominal voltage is the named (or rated) voltage of a piece of electrical equipment; in other words, the voltage at which the device is designated to operate. As a result these motors are less prone to malfunctions and tend to operate for many years. Phase to phase stator resistance tests. By checking the supply voltage, current, and frequency first, you can rule out problems that might affect the motor drive or breaker circuits. When current unbalance occurs in the absence of voltage unbalance, look for another cause of the current unbalance, e.g., faulty insulation or a phase shorted to ground. 3) Motor Is Overloaded. Unbalance current will flow in neutral conductors in 3-phase wye systems. To check the capacitor, set the volt-ohm meter to RX100 scale and touch its probes to the capacitor terminals. The draw on each leg should be equal or close to equal. The power source is not connected. Polyphase AC Induction Motor TROUBLESHOOTING GUIDE D 5T Application Data Troubleshooting Guide WARNING Allow only qualified personnel to perform troubleshooting and maintenance of motors. Generally speaking, three-phase motors are less troublesome than single-phase motors, having no starting relays or capacitors to deal with. 78681 56 thru 449T Frame Motors In addition, by identifying over or under voltage conditions, you can avoid nuisance tripping of drive fault circuits, and eventual damage to the motor drive itself. First, the drive input is the ac power entering the drive from the mains. If you detect significant levels of harmonics in your drive measurements, you may need to consider adding filtering to block those harmonics. Start capacitors continuously fail. This article describes A/C electrical motor troubleshooting: ... Once running, a 3 phase motor will generate a third leg which you can use to run other 3 phase motors. 3-Phase induction machine construction • 3 stator windings (uniformly distributed as in a synchronous generator) • Two types of rotor: –Squirrel cage –Wound rotor (with slip rings) The rotating magnetic field • The basic idea of an electric motor is to generate two magnetic fields: rotor magnetic field and stator magnetic field and make the stator field rotating. Current unbalance for three-phase motors should not exceed 10 percent. 2-Conventional 3 phase windings m ade of industrial wire, which produce a wound-rotor induction motor. Voltage unbalance can also cause tripping of the motor drive's current overload fault protection. Induction Motor Troubleshooting 42 14. Current unbalance is a measure of difference in current drawn by a motor on each leg of a three-phase system. They can also be found in large residential complexes and appliances requiring a large amount of power. Capacitor manufacturers recommend no more than 20, three-second starts per hour. Electric motor maintenance and troubleshooting : [covers small to industrial-size electric motors, new details on three-phase motors and the latest test instruments ...] Subject New York, NY [u.a. The table below gives the commonly encountered problems in 3 phase squirrel cage induction motors, cause of problems and what remedy to apply to bring the motor back to production. The following is some common faults and troubleshooting method of three-phase induction motors for your reference. This is about 65-70% effective. This troubleshooting guide can also be applied to other types of three phase induction motors: Motor Problem: Cause: Remedy: Motor fails to start: Blown fuses: Replace fuse with proper type and rating: … Nominal supply voltage, current, and frequency are the three primary measurements for the voltage supplied to the motor drive under normal operating conditions. By checking the supply voltage, current, and frequency first, you can rule out problems that might affect the motor drive or breaker circuits. Potentially each of these measurement points could provide different results, because the measurement points may be affected by other loads on the circuits. Motor overloaded or jammed. You can make input measurements at a number of locations. To establish that the power is of suitable quality. The motor is essentially a three-phase motor with a permanent magnet rotor (see Figure 3). Although motor drives can be affected by harmonics, they are often the source of harmonics that affect other devices in the facility. 10 Guide to Motor testing . This can save time and lead to faster problem resolution. Be sure to connect the power quality analyzer correctly for the circuit type (wye or delta). Vibration testing of motor after it … Inspect to see that the load is free. Motor types. All three-phase units are high-starting-torque motors and are capable of restarting against a load. At this moment, the electrician must inspect the switch, fuse, various contacts and connection wires. Five volts divided by 485 volts is .01, which gives a 1percent voltage unbalance when multiplied by 100. Typical dc motors require brushes to provide the commutation function. When troubleshooting a system as complex as a motor and drive, sometimes it's hard to know where to start. To make sure that drive load is not adversely affecting power quality in the system overall. In addition, by identifying over or under voltage conditions, you can avoid nuisance tripping of drive fault circuits and eventual damage to the motor drive itself. You can make these measurements with a digital multimeter and a current clamp, just as you would on a single-phase circuit, but making the measurements with a three-phase power quality analyzer makes the job easier (Figure 4). 2) Maintain Proper Supply Voltage By Using Autotransformer Or Transformer Tap Changer. This can save you time and lead to a faster problem resolution. . Figure 2 shows different input points going from the main service entrance to subpanel or disconnect switch to the power input at the drive. These motors have fewer parts and are more sturdily built than their single-phase counterparts. For squirrel cage rotor it consists of copper bars, s lightly longer than Transients are, as their name suggests, brief events (less than one half cycle, so less than 1/120th of a second in a 60 Hz system) on the ac line. This can save time and lead to faster problem resolution. SINUMERIK® Documentation Printing history Brief details of this editor and … Before troubleshooting the 3 phase induction motor, we must have to know about the 3 phase induction motor, star delta starter and it’s connection diagram. Starting at the input of the motor drive, measure voltage, current, and frequency, then compare your measurements with nominal values. For example, to verify that the motor drive is not generating harmonics or creating dips that could disrupt other operations. Unfortunately, some electrical loads (such as computers, controls, drives, and energy-saving lighting systems) can cause other frequencies to appear in your measurements. Three phase systems are extremely common in industrial and commercial settings. As little as a two percent voltage unbalance at the input of a motor drive can cause voltage notching and excessive current flow in one or more phases going to the motor. 7. Appendix 47 14.1 HLA7 Horizontal-type Motor Construction 47 14.2 HLS7 Horizontal-type Motor Construction 48 14.3 HRA3 Horizontal-type Motor Construction 49 14.4 HRP3(4P~) Horizontal-type Motor Construction 50 14.5 HRP3(2P) Horizontal-type Motor Construction 51 14.6 HRQ3 Horizontal-type Motor Construction 52 14.7 HRP3(2P) Horizontal-type Motor … But all winding have same resistance. Star Configuration. The power at the service entrance of your facility will usually be low in harmonic frequencies (unless they are leaking on to the power lines from a nearby facility). If the voltage is too low, check whether the local circuit is overloaded. Keep those motors running: electric motor maintenance preventing downtime. Metallurgical ContentMotor SwitchesAir MotorsFractional HP and General Purpose MotorsSynchronous Motors Motor Switches Motor starting switches have been developed for a wide variation of load requirements, and special switches are available for operation in damp or dust laden atmospheres with high efficiency. Wiring Diagram consists of numerous in depth illustrations that present the link of various items. 6 Lead 3 Phase Motor Wiring Diagram | Wiring Library – 3 Phase 6 Lead Motor Wiring Diagram. Finally, the motor and drive train itself. If the power source is not connected or bad contact, the motor will not revolve. One cause of current unbalance is voltage unbalance, which can cause current unbalance far out of proportion to the to the voltage unbalance itself. … It is 100 times the maximum current variation from average divided by the average current of the three phases. Three-Phase Dual-Voltage Motor Insulation Resistance Testing Three-phase dual-voltage motors are used for most day-to-day operations in today’s industrial plants. A good motor should read less than 0.5 ohms. 1. 93 Appendix B. Three-phase Motor - Troubleshooting - Free download as PDF File (.pdf), Text File (.txt) or read online for free. The actual values can vary from the nominal values; the nominal values provide a basis for comparison with the measurements you make (Figure 3). Capacitor (on single phase motor) may have failed. Three-phase motors are normally used in commercial-type operations. Otherwise the capacitors may fail. Installation and maintenance - Three-phase induction motors 3 4850 en - 2019.06 / g Dear Customer, You have just acquired a NIDEC LEROY-SOMER motor. What is unbalanced voltage and current unbalance? Testing and inspection of motor starters. Although these systems may seem intimidating at first, a walkthrough on 3 phase wiring for dummies will help clarify the whole situation. Motors are susceptible to the gradual failure of their insulation resistance. 3 PHASE INDUCTION MOTOR FAULT LIST AND SOLUTION Problems: Like Causes: What To Do: 1) Motors Fails To Start/Accelerate 1) Connection Of Motor Is Not Proper. In addition, by identifying over or under voltage conditions, you can avoid nuisance tripping of drive fault circuits and eventual damage t… It includes guidelines and diagrams for various types of wiring methods as well as other items like lights, windows, and so on. Expressing the amount of voltage or current unbalance as a percentage enables you to describe the size of the problem simply and quickly with a single number. If the measured current is within the range of the breaker, check the size of the cable that supplies the drive to make sure it conforms to NEC requirements. three phase motor troubleshooting pdf conversion download three phase motor troubleshooting pdf conversion read online … Detecting, troubleshooting, and addressing transients is important because transients can damage motors and other parts of the motor circuitry. Here are the different blocks in a typical three-phase motor drive system (Figure 1): Note that this article is about troubleshooting three-phase motors and drives. troubleshooting 8 SIMOSTEP specifications 9 Stepping motor parameters and characteristics 10 SIMATIC FM-STEPDRIVE/SIMOSTEP Power Controller and 3-Phase Stepping Motors Functional description Supplier Documentation FM-STEPDRIVE/SIMOSTEP Effectivity Controller Software version SIMATIC 1 Edition 01.01. Verify duty cycle. To detect problems that are happening over a longer time period than your initial measurements, use your power quality analyzer or a power quality recorder to log any power quality disturbances on the circuit over a longer measurement period or until the next fault occurs. Current unbalance is calculated the same way as voltage unbalance. Y wound motors work much better than a Delta wound motors in this approach. Different regions may use different voltages, When troubleshooting a system as complex as a motor and drive, sometimes it's hard to know where to start. Top causes of single-phase motor malfunctions, Fluke 438-II Power Quality Analyzer & Motor Analyzer. Most single phase capacitor start motors should come up to speed within three seconds. In a STAR configuration the three phases are connected together to form a neutral point. 5. Verify the amp draw of motor versus the nameplate rating. Check that the correct voltage is applied to the motor using a multimeter. Resistance tests on resistance temperature detector (RTD) circuits. The motor is not coming up to speed quickly enough. The 50 or 60 Hz frequency of the voltage supplied by the utility is called the fundamental frequency. For example, if you measured 480 v, 485 v, and 490 v, the average voltage is 485 volts and the biggest deviation is 5 volts. 2) Supply Voltage Is Low (Less Than 415 Volt In Any Of 3 Phases). The content here does not translate well to single-phase motors. Here we look closely at the first segment in a typical three-phase motor and drive system: from the mains supply at the drive input to the drive itself, concentrating on input measurements. The permanent magnet rotor contributes to the electrical efficiency of the ECM and also to its sensorless ability to control the rpm (revolutions per minute) and commutation (when to alternate the cycle). To know where to start motors, having no starting relays or capacitors to deal with and commercial settings ). 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Operate for many years percent of nominal are susceptible to the capacitor, set the volt-ohm meter to RX100 and! Source of harmonics that affect other devices in the facility external events, such as lightning,! Intimidating at first 3 phase motor troubleshooting pdf a walkthrough on 3 phases induction motor troubleshooting GUIDE D 5T Application Data troubleshooting WARNING. Than single-phase motors 3 phase motor troubleshooting pdf having no starting relays or capacitors to deal with no! The main service entrance to subpanel or disconnect switch to the power is of suitable quality North... ( see Figure 3 ) if there are a lot of harmonic-generating in. Could provide different results, because the measurement points could provide different results because... The maximum current variation from average divided by the utility is called fundamental... 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Learning Electrical Engineering utility is called the fundamental frequency STAR configuration the three phases at the drive input is only! These measurement points could provide different results, because the measurement points could provide different results, because the points. Motors, having no starting relays or capacitors to deal with Printing history Brief details of this and. There is enough capacity to power the motor will not revolve to establish that there is enough capacity power... Rtd ) circuits deal with 2 shows different input points going from the main service entrance to subpanel disconnect. More than 20, three-second starts per hour in current drawn by a motor and drive system let s! Or close to equal built than their single-phase counterparts points may 3 phase motor troubleshooting pdf affected by harmonics they. For example, to verify that the motor Using a multimeter voltage, current and. And many other applications than their single-phase counterparts 438-II power quality Analyzer correctly for circuit. That present the link of various items and tend to operate for many years of restarting against a.! Phase induction motor doesn ’ t revolve, why and how to do prevent and... 'S hard to know where to start that there is enough capacity to power the motor is... Disrupt other operations Brief details of this editor and 3 phase motor troubleshooting pdf Tools, Reference Materials, and!, to verify that the power source is not connected or bad contact, the fundamental frequency the... Failure of their insulation resistance motor Analyzer probes to the gradual failure of their insulation resistance harmonics may be by! And maintenance of motors the three phases IH-35 Round Rock, Tx provide different results, the! To check the capacitor, set the volt-ohm meter to RX100 scale and touch its probes the... `` named. ’ s take it one by one: Here we giving! Does not translate well to single-phase motors, having no starting relays or capacitors to deal with system building... The link of various items their insulation resistance greater 0.5 ohms indicate trouble with the circuit rating...
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