Diagnostics & Maintenance

This engineering domain includes the testing and analysis of the systems which are commissioned and already in operation. Such testing and analyses practices that are employed during the operation of a machinery are critical for two reasons viz., to prevent any breakdown from happening and to ensure its smooth running according to the functional requirements of the given machinery.

The problem solving in this demanding arena requires an engineer to possess thorough working knowledge of different kinds of equipment like bearings, gears, drives, motors, reciprocating machinery, turbines, pumps, etc. and use the appropriate fault diagnosis technique to identify any defects in the machinery. Envicon has a team of degreed engineers with a multi-disciplinary background who are adept at catering to your needs for system reliability, diagnostics and prognostics. We have rich experience in:

  • Condition Monitoring
  • In-situ Balancing
  • Diagnostics and Troubleshooting
  • Operating Deflection Shape Analysis

Condition Monitoring / Structural Health Monitoring

The process of extracting information about the health of a machinery or a system by monitoring one or more of the pre-identified parameters like vibration, temperature, current, etc. in order to identify a significant change which is indicative of a developing fault is called structural health monitoring. It is also commonly known as condition monitoring in the industry jargon and is a primary element of the predictive maintenance philosophy which happens to be the single largest maintenance philosophy followed in today’s industrial world.

Condition monitoring assesses the health of a machine by periodically monitoring and analyzing the data obtained during its operation and by trending the results against the levels of acceptability. The use of condition monitoring allows the maintenance to be scheduled or other actions to be taken ahead of time in order to prevent failure and avoid its consequences. It has a unique benefit in the conditions that would shorten the normal lifespan of a component and can be addressed before they develop into a major breakdown.

Envicon has received several annual maintenance contracts for the condition monitoring of both precision and process machineries from the leading process and manufacturing industries in the different engineering sectors and continues to be their valuable resource partner for condition monitoring related activities.

In-situ Balancing

An imbalance in a rotor is the most common source of vibration in the machines with rotating parts and can develop in an installed equipment due to various reasons like surface wear, welding repairs, etc. It often leads to excessive loading of the bearings causing them to fail due to fatigue thereby decreasing the useful like of the machinery. Rotor imbalance become an even more critical parameter in the design and operation of the machines where the high operating speeds and the system reliability are of significant concern.

In many situations balancing or re-balancing a rotor on a balancing machine is not only time consuming but is also extremely difficult and rather impossible due to the logistical constraints posed by the size and weight of the rotor. Envicon’s on-site balancing service is an answer to such situations. Envicon has so far carried out balancing of hundreds of rotors of different kinds of machinery and equipment. These include: 

  • High Speed Internal Grinding Spindles, Gun drilling Spindles, high speed spindles (operating speeds up to 100000 rpm), Machine tool spindles and fixtures.
  • Rotors of Electrical machinery – Motors, Alternators (weighing up to 25 tons)
  • Impellers, fans, blowers, flywheels of reciprocating compressors and pumps, couplings and many more
  • Vertical hydraulic turbine and generator shafts of plants with capacity ranging from 500 kW to 400 MW. 

Diagnostics and Troubleshooting

Vibration and noise diagnostics are aimed at identifying the source and the cause of vibration and noise problems of the machinery and equipment currently in operation. Various techniques such as frequency spectrum analysis, resonance testing, order tracking, etc. are employed for this purpose and the remedial measures to be taken are determined based on the results of the system diagnosis.

A team of engineers from Envicon visits the site with the required measurement systems and carries out the various tests to diagnose the problem. A detailed report based on the measurements along with the remedial measures is then prepared and presented as the deliverable to the client.

Typically, a newly installed machinery, a reconditioned and/or a repaired system often requires this service and on the basis of the type of the machinery, it can be classified as one of following two:

Analysis of Rotating Machinery

A rotating machinery based on its operating speeds can be categorized as a fixed speed or a variable speed machine. The measurement and the analysis techniques for the characterization of the noise and vibration of these two types of machines are quite different and require special knowledge of the advanced topics in the data acquisition and signal processing such as real time order tracking and waterfall measurement techniques. Envicon has analyzed a variety of both, fixed speed and variable speed machines, for bench marking, troubleshooting, acceptance testing and quality control. A few case studies involving rotating machinery analysis will typically include tracking of magnetic noise of an automobile alternator, vibrations of a hydro electric generator, vibration analysis of a marine engine, machine tool spindles etc.

Analysis of Reciprocating Machinery

The vibration analysis of reciprocating machinery is not only a meticulous and a tedious exercise but it has also boggled the industry for quite a while now because of the complexity of the forcing systems. Most of the reciprocating machinery vibrations are related to the foundation, compressor supports, imbalance, ducting etc. Envicon has developed a keen expertise in handling such problems and has an excellent track record of measuring, analyzing and solving any issues related to the vibration of the air/gas compressors and the IC engines.

Operating Deflection Shapes Analysis

Operating Deflection Shapes (ODS) analysis is a technique of determining the forced vibration response vector of a system under a given dynamic loading which is the combined result of its transfer function and the frequency of the forcing function exciting the system. In order to perform such an analysis, the response of the system is measured at various locations and directions and the signal is processed to determine the response vector. The input to the system is the ambient excitation present during its operation (engine, aerodynamic forces, etc.) and it is not measured.

Such an analysis helps in visualizing the vibration pattern of a system under the real-life operating conditions and by animating the spatially acquired data in the slow motion, the relative motion between the different subsystems or the components can be clearly viewed thereby making the hotspot areas prone to fatigue failure clearly visible.

One important point to be noted here is that an ODS analysis does not involve estimating the modal parameters of the system. Therefore it is quite different from an experimental or an operational modal analysis as are the signal processing techniques and the related computations.

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