Dc motor vibration analysis. Vibration analysis is a vital condition monitoring service for motors and rotating equipment, detecting early problems with equipment. Jul 6, 2023 · 2. The failed motors accumulated 6,522 hours of successful operation. However, due to This paper focuses on the electromagnetic vibration and its reduction in PM brush dc motors. He may be reached at blake@designmotors. However, the fault signatures are complicated and lack consensus. The vibration condition is classified as follows: - recently commissioned motor installation. Step 1: Analysis of Vibration Signal of BLDC Motor by ADXL335 Sensor. Sep 1, 2019 · Abstract. The gear transmission system model is established taking into account the time-varying meshing stiffness, static errors, and tooth surface friction, as well as other factors. W. m=¥ 1 Z p(r, f, z) = ¥ Pm(r,kz)eimfeikzzdkz m= å 2p ¥ ¥. One of the oldest and If the motor frame is vibrating more than 25 percent compared to the motor, it could relate to a weak motor base. Next, two types of vibration sources, called pulsating force and bending moment, are analyzed. May 1, 1995 · The Study of DC Motor Noise and Vibration. We have over 1. For most common analysis tasks, 400 lines of resolution is adequate, while more specialized tasks may require higher Oct 1, 2023 · Motor current signature analysis (MCSA) and vibration data are commonly used for diagnosing induction motor problems. Visual inspec-tion and electrical testing of the armature and fields give the maintenance personnel an under-standing of the condition of the motor. We will understand the DC motor construction and how a DC motor converts the supplied DC This dramatically improves processing speed; if N is the length of the signal, a DFT needs N 2 operations while a FFT needs N*log 2 (N) operations. In this article, the Permanent Magnet Synchronous Motor (PMSM) is driven by using sinusoidal pulsewidth modulation technique and then an investigation (cause and effect) of Acoustic Noise and Vibration (ANV) is presented. 5 – 3 V range – so the current is also limited. Our vibration motor longevity test machine. We also have the industry’s largest VPI In most cases vibration analysis will detect the abnormal Brinelling Brinelling typically occurs when there is a background vibration while the motor is not running. VELOCITY. When The rotation of the motor shaft is created by passing a current through the wire in a magnetic field, which creates a force. Figure 7 shows the BLDCM's Jun 5, 2023 · The vibration spectrum shows the discrete frequencies present in the vibration signal. (The oscillation may be periodic, such as the motion of a pendulum or random such as the vibration of mobile phone) In many cases, vibration is undesirable Aug 29, 2018 · This paper proposes a statistical fault diagnosis approach based on vibration analysis, applied to brushless DC motors. RMS vibration velocity. The small size of the motor limits the magnetic field, and therefore the force. The IPS North American network has multiple high-voltage service centers specializing in large and extra-large industrial AC & DC motors. Aug 10, 2023 · The paper introduces the theory of the model reference adaptive control (MRAC) with a view to minimize the effects of vibration of the brushless dc (BLDC) motor. Conclusion. Vibration signature analysis can detect faults such as bearing faults, unbalance, misalignment and gear faults. Finite Element (FE) based co-simulation modelling of a PM BLDC motor is used for obtaining the vibration spectrum of the machine under healthy and fault conditions. Electric motor vibration analysis is a critical aspect of maintaining the health and longevity of electric motors and generators. Then, two passive improvement methods Mar 7, 2017 · The brushless DC (BLDC) motor is widely applied in various industrial fields such as in oil/water pump driving motors, robots, and electrical vehicles due to its attractive features, namely, its energy efficiency, high torque, high rotational speed, and low noise level. This drive train consists of an electronically commutated DC motor and a shaft driven by it, which passes through a roller bearing. Rapid analysis of efficiency maps, torque/speed characteristics and drive cycles. Apr 19, 2018 · VIBRATION ANALYSIS By Mobius Institute:This video shares the answers to questions asked during the recent Mobius Institute live webinar, "An Animated Introdu Feb 15, 2022 · Noise and vibrations generated by an electric motor can be divided into three main contributors: mechanical, aerodynamic, and electromagnetic. The first step is to isolate the cause of vibration. A proposed method of vibration data acquisition using cloud technologies with high accuracy, feature extraction using spectral entropy, and instantaneous frequency and standardization using In the present work, three different types of measurements, cylindrical SONAH, structural impulse using an impact hammer, and a motor run-up test were matched to identify noise sources in a small DC motor. Divyasree [3] P. Blake Bailey is president of designmotors. BLDC motor drives are prone to position sensor misalignment and breakdown faults, which consequently cause torque and speed oscillations, affecting the drive system performance. An equivalent lumped Oct 30, 2020 · This paper discusses the fault diagnosis of the Permanent Magnet (PM) Brushless DC (BLDC) motor drive using vibration signatures of the motor. Based on the three main types of noise sources of motors, this paper firstly analyzes their Apr 3, 2024 · Single-phase brushless DC machines find extensive application in automotive auxiliary drives due to their cost-effectiveness. Aug 13, 2022 · Motor vibration and noise is an important index to measure motor performance. This research paper presents a performance analysis of electric motors using vibration measurement with an emphasis on the vibration measurement caused by bearing faults, loose ball bearing races, and rotor imbalance. In order to do the diagnostics there are analyzed vibration from the piezoelectric accelerometer. Actions to Take to Fix Motor Vibration. The spectrum has an f max of 384,000 cycles per minute (cpm) and 3,200 lines of resolution. Trending to track changes in the overall level of vibration helps determine when repairs need to take place. Rotating electric fields, etc. - vibration level that causes damage to the motor. In this paper, we present an IoT-based monitoring system for recording the Jun 6, 2022 · Like a lateral critical speed analysis, the RCF of a flange-mounted motor can be verified through impact hammer testing. Jul 1, 2011 · Fig. However, a DC drive gets its power supplied by an AC power source. The model has a back electromagnetic force (EMF) including vibration components and is constructed based on an electric circuit and transfer functions. 1 Electric motor noise. The emphasis owes to reflect the regulatory disturbances in terms of regulating the speed and therefrom observe the variations in the cogging torque, which contributes to be the Mar 20, 2020 · This paper deals with the anomaly detection of BLDC. 49 N-m, range 0–5 N-m for 12,000 rpm, manufactured by FUTEK) placed over PMSM and DC generator for vibration analysis. Nowadays the demands for condition monitoring and vibration analysis are no more limited trying to minimize the consequences of machine failures, but to utilize existing resources more effectively. Frequency spectrum and time domain plots are used to illustrate various Feb 15, 2018 · In the present work, three different types of measurements, cylindrical SONAH, structural impulse using an impact hammer, and a motor run-up test were matched to identify noise sources in a small DC motor. Save time and money on repairs in Knoxville. Jul 16, 2007 · In this paper, the influence of the stiffness and damping of real elastic shafts on the behavior of a multidrive system driving a tissue paper machine is investigated. net or 612-808-9913. 27. Chaitanya ,[2] G. IEEE. Gene Vogel EASA Pump and Vibration Specialist When a motor is test run in the service center, the two most common vibration frequencies that occur are at 1x rotating speed (1x rpm) and at 2x line frequency (2x lf). To Direct current is the flow of electricity in one direction (as opposed to alternating current which changes direction at a rate of 60 times per second). The problem is further complicated by the loading effects of the defect signatures. Left uncorrected, vibration increases stress on your assets, wastes energy and accelerates wear, resulting in failures, emergency repairs and costly downtime. p ( r, ϕ, z) = ∑ m = − ∞ m = ∞ 1 2 π ∫ − ∞ ∞ The shaft’s phase is the angular distance between a known mark on the shaft and the vibration signal. Therefore, continuous health monitoring, accurate fault detection and early warning of engine failures are essential and cost-effective. The accelerometer is mounted on the frame’s motor. Firstly, the air gap flux density distribution and radial force density distribution are derived in detail, and compared with the results of finite element method (FEM). Sep 19, 2014 · A magnification of the 1x to 3x peaks. An AC motor frequency domain vibration analysis. To record patterns in rotary machine behaviour and predict potential failures in advance. Figure 3 shows a higher-resolution fast Fourier transform (FFT) analysis taken without moving the sensor. A table listing faults, the principle vibration frequency, and comment on the signal characteristics and recommended correction is provided. mot or i n no n -stationary speed conditions using vibration signal analysis as well as extraction of several Condition. . Understanding their components and detecting common failures through vibration analysis is vital for their longevity. May 7, 2018 · A Study on Vibration Characteristics of Brushless DC Motor by Electromagnetic-Structural Coupled Analysis Using Entire Finite Element Model Abstract: A target of this study is to propose a 3-D entire finite element model to analyze the vibration characteristics of a brushless direct current motor for more accurate results. The surface gets damaged and will result in progressive flaking. Each type of fault, electrical faults or mechanical faults, produces a vibration whit a specific frequency. Figure 3. com/In this video we simply explain how to start your Predictive Maintenance, how to choose measurement point location and what the basic vibra Feb 13, 2020 · In this research, electric motors faults and their identification is reviewed. First, the air gap flux density distribution and the radial force density distribution are Feb 15, 2018 · The exterior and interior of a small DC motor with brushes used for noise measurements are. It is difficult to decipher this complex vibration waveform only in the time domain. This comprehensive guide will provide you with a deep understanding of the technical specifications, tools, and techniques involved in performing DIY electric motor This paper provides an over view of electric motor and generator principles, discussion of AC and DC motor construction, motor controllers, vibration data collection and processing. com/In this video we simply explain how to start your Predictive Maintenance, how to choose measurement point location and what the basic vibra May 5, 2021 · The magnetic field inside a machine is responsible for the mechanical excitation of the stator structure, generating vibrations and thus, audible noise. Vibration of DC motors using vibration and current signature analysis. Through monitoring and analyzing the vibration spectrum these specific frequencies can be detect and Sep 1, 2019 · Abstract. Regular and necessary maintenance with Abstract: In this paper, the acoustic noise and vibrations due to Maxwell forces of a 4-pole, 12-slot, high-speed brushless DC motor (BLDC) is analysed up to 90 kRPM. 951350. Nov 10, 2022 · This study proposes 1D modeling that considers the noise and vibration of a vehicle window-brushed DC motor. Initially the measurements were realized by using “healthy” DC motor Vibration analysis of electrical machines is comprised of two types of information: 1) vibration condition, which is usually evaluated with regard to special standards or specifications; and 2) data analysis, which allows for diagnosing of mechanical and electromagnetic problems in machinery, but these are not always related to excessive Jun 16, 2020 · In Mechanical pre-processing, a 3D finite element model of brushless DC motor, including housing, caps, bearings, and shaft beam, is built for comprehensive Multiphysics analysis. Frequency analysis is the basis of many powerful Dec 4, 2022 · December 4, 2022 by TechieScience Core SME. So for example, let’s take a signal length of 1024 (2 10 ); the DFT needs 1,048,576 operations compared to the much more efficient FFT and its 10,240 operations. The paper further describes the results of tests and diagnostics of Squirrel Cage Induction Motor malfunctions such as unbalance, misalignment, looseness, broken rotor Implementing motor vibration analysis techniques and methods provides valuable insights into the health of machinery, enabling maintenance teams to address issues before they escalate. The next spectrum was taken, using enveloped acceleration. This paper will present a comparison of vibration and motor current signals Jan 1, 2015 · This paper presents briefly some electrical and mechanical faults in induction motors and how these faults influence the motor vibration. Vibration Dec 8, 2020 · Motor vibration data contains substantial analytical information about stator and rotor winding and core condition, air gap eccentricity, current/voltage imbalance, and voltage distortions in the Vibration analysis is a process of looking for anomalies and monitoring change from the established vibration signature of a system. Six-pulse thyristor bridge power converters that are connected to the same power Large & extra-large AC & DC motor service and repair. This relationship is used for balancing and shaft orbital analysis (reference the Phase Section). 6 million square feet of repair space, with 145-ton lift capacity, and VPI tanks coast to coast. Jan 1, 2022 · Forced response vibration analysis of induction motor stators induced by electromagnetic forces Akira Saito ∗ Tatsuya Suzuki ∗ ∗ Meiji University, Kawasaki, Japan, (e-mail: [email protected]) Abstract: There is an increasing demand for efficient electric motors in various industrial fields, such as electric vehicles. Intuitive, template-based setups. This paper presents a comprehensive analysis of the vibration and acoustic noise for brushless direct current (BLDC) motor drive. shown in Figure 1. BLDC motor finds several applications due to their cost efficiency and simple construction. Jun 5, 2023 · The vibration spectrum shows the discrete frequencies present in the vibration signal. The motor's identification plate holds key information. A DC motor is defined as a class of electrical motors that convert direct current electrical energy into mechanical energy. These vibration signatures can be correlated to physical phenomena, making it possible to use vibration technique because of ease of measurement. From the above definition, we can conclude that any electric motor that is operated using direct current or DC is called a DC motor. Vibration analysis was used former mainly to determine faults and critical operation conditions. The rotor is devoid of any windings. Setting the resolution and fmax. Oct 27, 2012 · In this paper fault detection of permanent magnet dc motor is described. Identifying motor failures requires sophisticated signal processing techniques to detect and isolate faults quickly. After converting this information via fast Fourier transform (FFT), you can view it in the frequency domain, as in Figure 3. Finally, two passive improvement methods You can reach us through our quick solution form or you can give us a call at 1-800-829-7454. Presently, very little research has been performed using current signature analysis on DC motors. Vibration analysis can detect: Misalignment or bent Nov 22, 2023 · Mathieu S, Steven G, Jan A, Karl J, van der Auweraer H, Kevin V (2013) Nvh analysis of a 3 phase 12/8 sr motor drive for hev applications. High 1x rpm is often corrected by balancing, and the 2x lf is traditionally attributed to air-gap anomalies or voltage or winding unbalance. Sep 25, 2023 · Two primary types, DC and AC motors, play crucial roles, with squirrel cage rotor induction motors being the workhorse of choice for their simplicity and reliability. 4 and measured experimentally using in-line torque sensor (Torque constant = 0. Measured in in/sec or mm/sec, velocity measures the vibration signal’s rate of change in displacement. Apr 27, 2020 · Vibration signal captured from an AC motor in the time domain. How to reduce vibration and noise is one of the important topics in the field of motor design. “Vibration analysis is a powerful tool that helps us identify potential problems at an early stage, allowing us to schedule maintenance activities and avoid Most industrial system failures are caused by engine failure that can be very serious and cause significant downtime. The other 37 vibration motors that were still operational amassed 53,280 hours (1440 x 37). The vibration of any object in motion is characterized by variations of amplitude, intensity, and frequency. - unlimited satisfactory long time operation. Unbalance Classification Using Vibration Data (Vibration Measurements on a Rotating Shaft at Different Unbalance Strengths): This dataset contains vibration data recorded on a rotating drive train. Also, there is little use for miniature vibration motors above 24 V and most are around the 1. First, the air gap flux density distribution and the radial force density distribution are Nov 21, 2023 · of a 4kW BLDC motor is highe st in the X-direction and increases as the time or RPM range increases. The vibration velocity of a 4kW BLDC motor is a good indicato r of the health of the motor Apr 16, 2021 · With this aim, Motor Current Signature Analysis (MCSA), speed, torque, noise, vibration signals, etc. 24 mm Motor vibration analysis performed by Technomax helps in detecting and resolving motor faults. [02] 2. Analysis, calculation, and reduction of motor vibration and noise have attracted more and more attention from motor designers. 9. Included are various methods and techniques to reduce or attenuate the levels of noise and Jan 17, 2024 · An analysis is conducted on the vibration characteristics of the electromechanical coupling system that connects the motor and the gear. The maximum possible resolution is 120 cpm. A 3D model has been generated approximately to the real This paper focuses on the electromagnetic vibration and its reduction in PM brush DC motors. If the vibration remains after asking the 10 questions above, conduct a vibration troubleshooting analysis to find the exact source. This paper focuses on the electromagnetic vibration and its reduction in PM brush dc motors. The frequency at which these events occur can indicate the source of the vibrations. It aids in saving production costs and valuable time. Also, for the current measurement it’s used ampere sensor. In this study, a novel approach for a non-invasive technique, based on vibration anal-ysis for condition Feb 13, 2020 · In this research, electric motors faults and their identification is reviewed. Typically, single-phase brushless DC drives require a Hall-effect sensor to determine the motor's position to facilitate motor control. Akshitha [1] Asst. The major advantages of BLDC motors are low maintenance, high efficiency, long life, low weight and compact construction. - short-time operation. First, the model of an inverter-fed permanent magnet motor, simulated using Jan 1, 1999 · Vibration velocity signals overlaid with frequency analysis module (FAM)—electric motor from Figure 5-66, Figure 5-67. The exterior diameters of 12 V DC motor housing and armature were 3 4 mm and. The electrical and mechanical components of the brush DC motor are included, creating a model that considers noise and vibration. In past, Current Signature Analysis (CSA) has become an established tool for online fault analysis of AC induction motors. In Electric Vehicle Symposium and Exhibition (EVS27), 2013 World, pp 1–10. Feb 15, 2022 · Noise and vibrations generated by an electric motor can be divided into three main contributors: mechanical, aerodynamic, and electromagnetic. The drive system consists of four DC motors, where two of them drive the Yankee drying cylinder and the other two drive the presses section. 27 shows the vibration velocity measured at the centre of stator surface, when the motor is running at no-load. However, compared to their three-phase counterparts, these machines exhibit higher levels of noise and vibration. The noise and vibration characteristics of permanent magnet direct current motors along with the associated primary sources of noise, vibration and transmission paths are presented in this paper. Implementing a predictive maintenance program takes a PM program to the next level. However, there are those cases where the Dec 12, 2018 · https://adash. 61-68 Sep 13, 2016 · Brushless DC motor, vibration signal analysis, gray model, fault prediction, gray safety assessment model Date received: 13 September 2016; accepted: 1 February 2017 Academic Editor: Yangmin Li Introduction The brushless DC (BLDC) motor is widely applied in various industrial fields such as in oil/water pump driv- Sep 17, 2018 · Analyzing motor vibrations should be easy enough – right? After all, the only moving part is the shaft and rotor assembly. It provides us with detailed information about the root cause of the machine faults. Setting the number of lines of resolution and the fmax are essential first steps for the vibration analyst. Flux Switching Motor (FSM) with segmental rotor is a new class of electric motor, with both AC and DC windings on the stator. Then two types of vibration source, called pulsating force and bending moment are analyzed. Fault analysis occurring in the electric motor was made following the ISO 10816-3 Standard. Most component equipment: gear box Mar 15, 2024 · Electromagnetic analysis was performed for different load conditions and various electromagnetic vibration causes, such as torque ripple, back electromotive force (EMF), and unbalanced magnetic force (UMF) at the same output and power. Since AC power is a sinusoid, the drive cuts off the bottom ("-" portion) of the sine wave in order to get a constant "+" voltage. distinct RPM ranges, spanning from 1280 to 3800 RPM and from 3800 to 7500 RPM. FSM with its high torque density, compactness, less heat production and high ruggedness can prove to be an ideal motor topology to be used for the propulsion systems of In the present work, three different types of measurements, cylindrical SONAH, structural impulse using an impact hammer, and a motor run-up test were matched to identify noise sources in a small DC motor. The harmonic magnetic forces present in the machine are first analytically characterized, and validated with numerical simulations using MANATEE ® electromagnetic and vibro-acoustic software. The rapid development of power electronics and control technology due to the electrification trend has created space for different types of electric motors in electric vehicles like Brushed DC motors, brushless DC motors, permanent magnet synchronous motors (PMSM), 3-phase AC induction motors, switched reluctance motors (SRM) [38, 39]. The sound pressure on a cylindrical surface of radius r can be expressed as. Mechanical noise and vibration are related to manufacturing or mechanical conditions like friction, alignment or lubrication faults, and loss of contact between bearings, gears, and other interfaces. com. 1–3 However, a growing number of applications rely on BLDC motors, which has increased concerns over its reliability and Vibration Analysis is the primary tool used in Condition Monitoring to analyse machine health. This will cause the lubrication film to be pushed away, causing a cold-welding action between the roller and raceways. The continuous operation of a PM BLDC motor in industrial applications steers to Nov 16, 2020 · In Mechanical pre-processing, a 3D finite element model of brushless DC motor, including housing, caps, bearings, and shaft beam, is built for comprehensive Multiphysics analysis. This paper is a brief introduction to fault diagnosis of DC motors using vibration and current This paper presents a comprehensive review of a permanent magnet brushless DC motor's (BLDC motor) fault diagnosis combining vibration and current signals collected from sensors. Dec 16, 2023 · The performance of a Brushless DC Motor (BLDCM) in terms of energy and power across two. 1) What is vibration? Vibration is a mechanical phenomenon whereby oscillation occur about an equilibrium point. Vibration analysis for electric motors is used to detect electric motor potential problems. Mar 12, 2024 · Many of these vibrations are directly related to periodic events that occur during the operation of the machine, such as: Rotation of a motor shaft, The meshing of gear teeth, and. To diagnose and establish root causes of rotary asset failure. A proposed method of vibration data acquisition using cloud technologies with high accuracy, feature extraction using spectral entropy, and instantaneous frequency and standardization using Jul 28, 2020 · The vibration of the motor provides information for failure diagnostic and prediction through signal processing. ar e exploited under different condition- monitoring methods according to the investigated Dec 31, 2015 · The MPU6050 module is a popular tool for measuring vibration signals from the motor in all three axes X, Z and Z [38], it is positioned noninvasively in an axial position on a rigid surface, near Vibration Analysis is the primary tool used in Condition Monitoring to analyse machine health. This gave a total of 59,802 operational hours from 43 units under test. Built-in electromagnetic, thermal and mechanical solvers. For most common analysis tasks, 400 lines of resolution is adequate, while more specialized tasks may require higher The limit values for the vibration severity values are defined by ISO 10816-1 depending on motor classes. You can also contact us by email at info@tekwellservices. Apr 16, 2021 · In this study, a novel approach for a non-invasive technique, based on vibration analysis for condition monitoring of brushless DC motor drives, is presented. With proper analysis, resonant vibration problems inherent to a drivetrain design can be resolved. First, the air gap flux density distribution and the radial force density distribution are derived in detail, and compared with the results of the finite element method. This project investigates the source of noise and vibration in an 800 W BLDC hub Motor used in an Electric Scooter. This analysis helps us in planning the required maintenance and repairs. Dec 12, 2018 · https://adash. Orpin,"Current and vibration monitoring for fault diagnosis and root cause analysis of induction motor drives", Proceeding of the thirty first turbomachinery symphosionum 2002, pag. 7,8 The harmonic components of the electromagnetic vibration source under AC and DC load conditions were Feb 9, 2023 · Brushless DC (BLDC) motors are the most commonly used electric vehicle motors but one of their major drawbacks is the acoustic noise and vibration caused by torque ripples. DC motor fault zone analysis is a vital part of any DC motor maintenance program. Bearings contain 4 elements that can deteriorate with the usage: the inner and outer race, the The article discusses how the electric motor and coupled machine design and malfunction behavior is reflected in the current spectrum using Motor Current Signature Analysis and in the vibration spectrum using Vibration Analysis. At DMS we encourage regular surveys at fixed intervals to enable our customers to build up a previously mentioned, there are only a few studies using vibration analysis for fault de-tection in BLDC motor drives and only in [33] vibration signals are used for position sen-sor misalignment fault diagnosis under a multi-sensor scheme. At DMS we encourage regular surveys at fixed intervals to enable our customers to build up a Jun 13, 2019 · Abstract. The results obtained from the analysis will be used as references and guidelines for Torque response (τ) at the motor shaft of PMSM is shown in Fig. Indicato rs (CI Jan 27, 2021 · Rotating machines generate vibration that can be analyzed to asses the general condition of machines and the remaining life of their parts. The vibration of 600 through 650 Hz is mainly emitted from the natural frequency, and 100, 200, 400, 500, 700, 1000 and 1200 Hz are corresponding to the frequency of the radial force with mode 4. The use of vibration monitoring and motor current signature analysis can help determine problems within an AC motor that can either be repaired or scheduled for planned maintenance downtime. However, few applications are acoustic noise and Vibration Analysis of DC Motor with ADXL335 and MATLAB [1] T. Professor Balaji institute of technology and science, Warangal,Telangana Abstract: -- Most of the failures in the industrial systems are due to motor faults which can be catastrophic and cause major downtimes. The enveloping circuits degraded all the machinery noise and their harmonics, leaving just the repetitive signals generated by the bearing. Brushless direct-current (BLDC) motors stator fault identification using long short-term memory neural networks were analyzed. Daniel F, Calin H, Cristi I (2016) Noise and vibration behavior evaluation of dc motor and pmsm in electric traction A template-based design tool for multiphysics analyses of electric motors across the full torque-speed operating range to optimize EV performance, efficiency and size. Thomson, P. Since the insulation break in the stator winding is the most commonly occurring fault in the stator, a short-circuit was artificially created between two windings. sfkhnmhkdzrbaxyrwvey
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