It focuses maintenance and operations by predicting functional failures, future failure mode and estimating time of failure; conveniently schedule targeted proactive failure interventions and prevent loss of production availability.
Improve reliability of equipment
Decrease maintenance cost and maximizes returns, reduce labour and material cost needed for preventive maintenance routines, minimize energy consumption, increase product quality, increase production capacity, reduce spare parts inventory, give consistent equipment performance, provide reliable production, increase equipment availability, lowers downtime, increase asset life, reduce overhauls.
Optimize preventive maintenance routines for the equipment
Avoid health and safety and environmental risks and thus cause healthy environment
States the details of failures and repair requirements in the equipment
Maintenance
Is the process of testing which is performed for identify equipment problems and also diagnose equipment problems to confirm that repair measures have been effective
The different Types of Maintenance are Breakdown Maintenance, Preventive Maintenance, Corrective Maintenance, Maintenance Prevention.
Maintenance types
1. Breakdown
It means that people waits until equipment fails and repair it. Such a thing could be used when the equipment failure does not significantly affect the operation or production or generate any significant loss other than repair cost.
2. Preventive
It is a daily maintenance for retaining the healthy condition of equipment and prevent failure through the prevention of deterioration, periodic inspection or equipment condition diagnosis, to measure deterioration. It is further divided into periodic maintenance and predictive maintenance.
2.1. Periodic ( Time based - TBM)
Time based maintenance consists of periodically inspecting, servicing and cleaning equipment and replacing parts to prevent sudden failure and process problems.
2.2. Predictive
This is a method in which the service life of important part is predicted based on inspection or diagnosis, in order to use the parts to the limit of their service life. Compared to periodic maintenance, predictive maintenance is condition based maintenance. . Thus causes predictive action
3. Corrective
It improves equipment and its components so that preventive maintenance can be carried out reliably. .This causes corrective action.
Predictive maintenance (PDM)
Techniques which states the condition of the service equipment in order to predict when maintenance should be performed in the machine. This approach offers cost saving and repair
PdM, or condition-based maintenance, attempts to evaluate the condition of equipment by performing periodic or continuous equipment condition monitoring. The ultimate goal of PdM is to perform maintenance at a scheduled point in time when the maintenance activity is most cost-effective and before the equipment loses performance within a maximum limit. This is in contrast to time- and/or operation count-based maintenance, where a piece of equipment gets maintained whether it needs it or not. Time-based maintenance is labor intensive, ineffective in identifying problems that develop between scheduled inspections, and is not cost-effective.
The "predictive" component of predictive maintenance aims the goal of predicting the future trend of the equipment's condition. This approach uses principles to determine at what point in the future maintenance activities will be appropriate.
Most PdM inspections are performed while equipment is in service, thereby minimizing disruption of normal system operations. Adoption of PdM can result in substantial cost savings and higher system reliability.
Technologies
To evaluate equipment condition, predictive maintenance utilizes nondestructive testing technologies such as infrared, acoustic, corona detection, vibration analysis, oil analysis, and other specific online tests. New methods in this area is to utilize measurements on the actual equipment in combination with measurement of process performance, measured by other device
Industrial vibration analysis is a measurement tool used to identify, predict, and prevent failures in rotating machinery. Implementing vibration analysis on the machines will improve the reliability of the machines and lead to better machine efficiency . Vibration analysis programs are used throughout industry world wide to identify faults in machinery, plan machinery repairs, and keep machinery functioning for as long as possible without failure.
Machines affecting vibration
Typical machines include motors, pumps, fans, gear boxes, compressors, turbines, conveyors, rollers, engines, and machine tools that have rotational elements. The rotating elements of these machines generate vibrations at specific frequencies that identify the rotating elements. The amplitude of the vibration indicates the performance or quality of machine. An increase in the vibration amplitude is a direct result of failing rotational elements such as bearings or gears. Based on the machine speed, the rotational frequencies can be calculated and compared to the measurements to identify the failure mode.
INTRODUCTION
The electrical motors are very often used machines in many applications. The service live of these machines is very important parameter. The service life is dependent on the quality of sliding contact. The sliding contact is composed of brush, brush holder and commutator . The brush lifetime depend on many circumstances. The quality is the major factor. The shape knowledge of running commutator on nominal speed level is useful. It is the reason to developed the contactless measurement with induction probes. The probes use the eddy current effect to sensing the placement of the electrical conducting materials. Measuring workplace was developed on Department of power electrical and electronic engineering. Measuring chain is composed of the induction probes, the central unit, the oscilloscope, the personal computer . The induction probes signal is connected to central unit. The central unit fit level of the probe output voltage for the oscilloscope. The oscilloscope view the waveform of the measured voltage. The optical reflective Infra Red sensor is used to the probe waveform focus on the oscilloscope. The waveform determine the surface of measured rotating object. There is marked additional stiffness bar for vibration decreasing. The rotating motive motor and clutch cause the spurious vibration. These mechanical vibration makes a little commutator displacement and makes the measuring error and makes lower accuracy.
Industrial Vibration Analysis
Measurement of vibration
Analyze of vibration
Alarm ringing
Repairs on the parts
Industrial Vibration Sensors:
The practice of Vibration Analysis does require the measurement and analysis of rotating machines utilizing different vibration sensors (accelerometers, velocity transducers, or displacement probes). The most common sensor used in industry is the accelerometer.
Accelerometers are case mounted using a permanent bolt or portable magnet to hold them in place. They will measure the vibration of the machine and output a voltage or current proportional to the vibration and relative to a "g" level. This signal can also be integrated to provide a measured output of velocity. We have to choose the correct accelerometer, cable, connector, and mounting method for each application. This will provide good results for identifying faults in rotating machinery. Sleeve bearing applications require displacement probes to measure the actual movement of the shaft inside the bearing
These non-contact probes measure the vibration of the shaft and the gap between the shaft and the internal diameter of the bearing. Using an eddy current process, these probes will provide an output voltage equal to displacement .
Accelerometer
Accelerometer are available to detect magnitude and direction of the acceleration ,it gives a vector quantity, and can be used as a device that measures proper acceleration, the acceleration experienced relative to sense orientation, acceleration, vibration shock, and falling. Micro machined accelerometers are increasingly present in portable electronic devices and video game controllers, to detect the position of the device or provide for game input.
Accelerometers have been used widely in monitoring applications. It is used for vibration monitoring. It is a small, light weight probe with a wide frequency ranges of working ability. This probe is attached to the machine housing. It is attached to the machinery which will have parts that generate high frequency signals,.
The application of an accelerometer must be carefully checked for the accuracy and sensitivity.
Accelerometers is connected on machine housing. This will provide continuous or periodic sensing of absolute motion in terms of acceleration.
Operation of accelerometer
Accelerometers is a devices which convert mechanical vibrations to an electrical signal. This signal is proportional to the vibration's with the help of the piezoelectric principle. Inertial measuring devices measure motion relative to a mass.
Accelerometer is a piezoelectric crystal and its mass normally kept in a strong metal case. As force is applied to the crystal, the crystal creates a energy proportional to the force. The energy output is in terms of Pico Coulombs per g (pC/g) terms where g is term for gravity. Certain sensors have an internal amplifier, while others have an external ones. The charge amplifier converts the charge output of the crystal to a proportional voltage output in mV/g terms.
Calibration
Accelerometers cant neither be recalibrated nor adjusted. Like a velocity pickup it phase, this transducer have no parts undergoing to normal wear. Therefore, there is no need for the output sensitivity to be corrected for wear.
An accelerometers consist of internal components which may get damaged from sudden jerk or overwarming. When an accelerometer is subjected to, a simple test of the transducer's bias voltage will help decides whether it should be removed from usage. An accelerometer's main voltage is the directly related of the transducer's output signal. The bias voltage is measured with a DC volt is directly proportional to across the transducer's signal output and common leads with power applied. At the same time, the power supply should also be checked to remove the possibility of irregular power voltage affecting the voltage level.
Sensitivity
The sensitivity of accelerometer is 100 mv/g
With this sensitivity it is more effective than other probes. Accelerometers can be made different of sensitivities for special applications such as structural analysis, geophysical measurement.
Frequency Range
Accelerometers are capable of measuring vibrations of different frequency range. Once the particular frequencies of a machine is known, then an accelerometer may be selected. for measuring vibration of the machine having frequency ranging from one hertz to 10k hertz.
An accelerometer is used on devices where high frequency measurements is to be measured. The energy sensed by the transducer, acceleration will have larger amplitudes as the frequency increases. The best frequency between which an accelerometer works is between 1 hz - 10 khz between this the accelerometer is said to be working in its best capacity. At least frequencies, the acceleration amplitudes may be small giving a wrong impression of an ability of the machine.
Current Mode
It has as has an internal, low-output impedance amplifier and requires an external energy source. The external energy source is an constant current source or a regulated voltage source. This accelerometer is normally a two wire transducer with one wire for power and signal, and the second wire form common terminal. This type of Accelerometers has a min: temperature range due to the internal amplifier circuitry. Signal which send the cable are of high quality and frequency . Longer cable lengths will reduce the effectiveness of frequency response range.
Charge of Mode
Charge of mode accelerometers differ slightly from current mode types. These sensors have no internal amplifier and so work on a higher temperature . An external charge amplifier is attached with a special adapter cable which is connected to the accelerometer. Field wiring is removed from the external charge amplifier. As with current mode accelerometers, signal cable lengths up to 50 feet have negligible effect on the output . Longer cable lengths will reduce the effective frequency response range in a dramatic way.
Types of accelerometers
The working of accelerometer is greatly influenced by temperature with respect to that it is classified into various classes.
A low cost accelerometer which works on 200 Fahrenheit (93c) it's effectiveness is low when compared. I
A 250 fh (121c) accelerometer which works on higher temp: and is more effective when compared
A 359 fh (177c) accelerometer which too works on a higher temp:and is the most effective when compared.
Efficiency
the instrument has an "accuracy" of 92% or better.
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BNC Junction Boxes
The CMCP-300 series is a BNC Junction Boxes are multiple channel connecting centers for terminating the outputs of accelerometers
The CMCP-300 Series Junction Boxes are available in three (3) versions, NEMA 4x Fiberglass, NEMA 4 Powder Coated Steel and NEMA 4x Stainless Steel. Both internal and external BNC models are available. They can be found on both internally and externally circuited.
Cables Connectors
CMCP-603L Standard 3-Pin Accelerometer Extension Cables
CMCP-602H High Temp. 2-Pin Accelerometer Extension Cables
CMCP-603H High Temp. 2-Pin Accelerometer Extension Cables
CMCP-604 Low Cost 2 Pin Accelerometer Extension Cables
CMCP-625 Accelerometer 5015 Connector to BNC Adapter
CMCP-630 A/B Switch for Micro log
CMCP-660 BNC to BNC Extension Cables
CMCP-665 BNC to Fisher Cable for SKF CMXA50
For accelerometer or phase inputs into the SKF CMXA50 data collector
Damages Identified by Vibration Analysis:
Faults occurring in vibration are -
Unbalanced machine
Misalignment
Resonance
Bent shafts cause vibration
Irregular Gear mesh
Improper blade disturbances
Improper Vane pass disturbances
Recirculation & Capitation
Motor faults
Bearing failures
Mechanical looseness
Critical machine speeds
Dynamic Vibration Analysis:
The measurement and analysis of dynamic vibration involves accelerometers to measure the vibration, and a data collector to collect the data. Analysis is usually completed by a trained engineers in the field of rotating machinery vibration.
The analog voltage output of the accelerometer, 100 mV/g, is measured by the data collector and presented as a Time Waveform and FFT for frequency identification
The plots of amplitude vs. time and amplitude vs. frequency are required for the trained engineer to analyze and determine the machine prblems. Since each rotating element generates an identical frequency, analyzing the frequency disturbances will identify the faulty element. Once the fault is identified, repairs are done to the nessary parts
Dynamic vibration analysis can be accomplished by-
Portable sensors and data collector
Permanent sensors and portable data collection .
Permanent sensors and permanent data collection that provides machinery protection 24 hours/day, 7 days/week, 52 weeks/year.
Vibration Alarms:
A recent development in the predictive maintenance and reliability market is to leverage the investment already made in process control systems (PLC). This allows the operations, maintenance, and process control teams to monitor and alarm vibration levels on critical machines. Using a standard
4-20 mA output, the loop power vibration transmitters and sensors provide a current output proportional to the overall value of the machine vibration. This is not a dynamic analog signal, and it can not be used to analyze the machine fault, but it can be used to alarm the machine and indicate when vibration levels are too high. When high vibrations are measured by the process control system, action can be initiated to determine the cause of the vibration or shut the machine down to prevent damage and failure.
Loop power 4-20 mA outputs can be achieved using three different methods.
A dynamic accelerometer with a 100 mV/g analog output can be connected to a transmitter. The transmitter provides signal conditioning and a 4-20 Ma current output proportional to vibration. It offers several different frequency filters to alarm the region of interest. The dynamic signal, 100 mV/g, is also available for the trained technician or engineer to analyze.
A loop power sensor with a direct 4-20 mA output can also be used. This sensor does not require a transmitter, but the frequency filters are limited to
10 - 1000 Hz and 3 - 2500 Hz.
A dual output loop power sensor with a direct 4-20 mA output and secondary 100 mV/g dynamic output can also be used. This sensor does not require a transmitter, but the frequency filters are limited to 10 - 1000 Hz and 3 - 2500 Hz. It does have the dynamic signal, 100 mV/g, available for the trained technician or engineer to analyze. No matter what method you choose, standard 4-20 mA outputs proportional to machine vibration are available for process control. This allows the factory to leverage typical process control monitoring methods and alarm schemes. Convenient alarms for critical machines!
ADVANTAGES
Advantages of this technique
Rotating equipment such as motors, pumps, blowers, fans, gear turbines can be kept in check
Interconnected structures, static equipment and piping
unbalance
Misalignment
Looseness
bent shaft
Gear problems
bearing problems
Motor internal faults
Electrical grounding faults
Noise excitation (piping/structural)
Summary of vibration analysis
Over the last 100 years, this technology has been refined for today's industrial market to provide fast effective measurements of rotating machinery vibration. Sensors have been made to withstand the harsh industrial environments and provide critical measurements year after year. . Junction boxes are extremely useful in collecting multiple cables and organizing them in a manner that protects them and makes them accessible to the user. They prevent tangled cables and identify each measurement point. Dynamic Vibration Analysis or Process Vibration Alarms will provide a proven technology to predict failures in rotating machinery and improve machine reliability.
Cables and connectors are constructed of the most rugged materials available, and provide the critical link from the sensor to data collection. Designed for all types. Mounting hardware is available for a broad range of applications. Measurements are accomplished quickly with portable magnet mounts or quick disconnects. Permanent sensor installation can be accomplished with stud mounting,
So we must all take a decision to protect your investments by using CTC Industrial Vibration Sensors, Cables, Connectors, Mounting Hardware, & Junction Boxes!
Conclusion
Thus with the help of this paper presentation it can be stated that with the help of vibration analysis companies can reduce the amount of damages and break down happening to there firm.
Thus in all ways vibration analysis is good for a well organized manufacturing firm.
