Shaft vibration

Expert Vibro devices are capable of acquiring, analysing and monitoring up to 16 synchronous shaft vibration sensors. Both static and dynamic movement is measured of journal-bearinged, rotating shafts in relation to fixed bearing housings. Radial shaft position and rotation is also acquired via a KeyPhasor reference on the shaft. Phase information is computed from the shaft position.

The Expert Vibro device can directly compute spectrums and characteristic values such as smax or Peak-Peak from the measured time signal. The device independently records the data, or transmits it via Ethernet or PROFIBUS-DP to DCS-systems or PCs. The ProfiSignal software and Vibro option enable users to portray and evaluate measurement data in FFT or orbit diagrams.

Shaft vibration systems are typically found in hydro-power machines, steam/gas turbines or compressors.

Benefits of Inobalt products

• Evaluation of peak to peak spp and maximum deflection smaxmax according to VDI2059
• Sensor – wire break - monitoring
• Monitoring of static shaft position
• Monitoring of dynamic shaft vibration
• Analysis within device / frequency band monitoring
• Speed measurement and triggering via impulse from rotating shaft
• Process and vibration measurement in a single device
• Intelligent recording within device
• Visualization and analysis using time signal, trend spectrum, cascade and orbit diagrams

Gear box test stands using vibration measurement systems

Inobalt cooperates with other company to advise, design, plan and supply test stand measurement systems for the inspection of gear units. The measurement systems are made up of special vibration velocity sensors, one or more Inobalt AMDT modules for signal processing and the ProfiSignal evaluation software. The system has a range of interface options to enable its integration into existing hardware and software set ups.

The measurement system enables user to, for example, determine vibration values for gear units (fingerprint), signal analysis, data archiving, in-depth analysis of data with assessment on series production. This also enables users to perform acceptance tests for gear units (geometry) according to ISO 8579-1/2 using vibration velocity inspection and quality inspections for airborne-sound gear meshing.

Product features

• Synchronous and parallel acquisition of up to 16 vibration signals
• Digital signal processing (DSP)
• FFT computation and monitoring directly within Message device
• Determination of characteristic values (Peak-Peak, Gap), order analysis
• Characteristic value monitoring and alarm notification (text messaging, email)
• PROFIBUS-DP or Modbus RTU/TCP interface to enable reporting to main control systems
• Measurement data trends and analysis using ProfiSignal and data networks
• Evaluation using orbit, FFT, cascade and XY graphs
• Calculation of envelope frequency spectrum and vibration speed

Benefits of Inobalt products

• Quick detection of test sample weakness via signal imaging analysis
• Quality control via detailed acceptance of gear units
• Simultaneous acquisition of vibration and process measurement data
• Data logging for data security
• Universal connection to acceleration, speed and distance sensors
• Compact design, modules equipped for high channel density (suitable for cabinet installations)
• Very cost effective

Casing vibration

Vibrations occur frequently in machinery and test stands. High levels of vibration can lead to inefficient performance and/or unintended shutdowns.

Expert Vibro devices can process the signals from different vibration sensors. Expert Vibro devices differ to other systems by their ability to process unfiltered measurement data. Processing takes place of vibrations in the 0 - 20,000 Hz frequency spectrum. The frequency spectrum often enables users to determine excitation frequencies. Excitation frequencies are required to enable users to improve vibration performance.

The Expert Vibro device is able to continuously acquire and monitor the level of damaging frequencies. The devices can function fully independently due to their integrated data logging capability.

Visualisation takes place using Inobalt's ProfiSignal software. Users can portray their measurement data as cascade, frequency spectrum or trend diagrams. This provides all the prerequisites for an immediate and fast analysis of vibrations. The vibration data can be saved via LAN to a server database and then analysed.

Benefits of Inobalt products

• Connectivity for any type of vibration sensor
• FFT analysis within device / frequency band monitoring
• Evaluation using frequency spectrum
• Monitoring of vibration levels
• Process and vibration measurement in a single device
• Intelligent data logging within device
• Visualization and analysis using time signal, trend spectrum, FFT, cascade and orbit diagrams

Bearing vibration

Diagnostic procedures on bearing systems are an essential part of modern systems of preventative maintenance. Condition Monitoring Systems (CMS) are being used increasingly for machine diagnostics. Many of these systems are based on bearing vibration measurement. The systems are required to perform diagnostic qualitative procedures (envelope spectrum) and quantitative procedures (vibration velocity). Inobalt's Expert Vibro devices are capable of performing both types of procedure.

Different types of velocity sensor are in use. These have high cut-off frequencies and good levels of resolution. Expert Vibro devices can compute envelope spectrums from the time signals of velocity sensors. An envelope spectrum delivers detailed information on the state of a bearing. For example, the spectrum can reveal the state of the inner and outer rings, the bearing cage and the ball bearings. The ProfiSignal software and Vibro option enables users to portray and evaluate envelope spectrums.

The quantitative procedure converts the velocity sensor's time signal into vibration velocity. A Expert Vibro device is able to perform this conversion directly online. The vibration velocity is then usually monitored as a sum level.

Benefits of Inobalt products

• Evaluation of vibration strength veff according to DIN ISO 10816
• FFT analysis within device / frequency band monitoring
• Evaluation of bearing damage diagnosis using envelope curve frequency spectrum
• Monitoring of vibration levels
• Intelligent recording within device
• Visualization and analysis using time signal, trend spectrum, FFT cascade, and orbit and polar diagrams

Air gap measurement

Inobalt's Expert Vibro devices are used to measure air gaps on generators.

Narrow distance sensors are installed at the stator. Measurement is non-contact. The rotor generates an equidistant signal for each rotor pole passage.

The sensor system is made up of an air gap sensor and a module for signal feed and conditioning. The air gap sensor is usually fixed to the stator. Measurement typically ranges from 1 ... 50 mm.

The Expert Vibro device records the time signal (distance) from each air gap sensor for each turn of the rotor. Synchronous triggering takes place via a digital rotation pulse.

Each rotor pole is portrayed with a negative signal level. The Expert Vibro device automatically determines the minimum air gap and a chronological pole position that can be converted into phase information in the 0 … 360° range. The data then enables a rotor profile to be portrayed (as polar coordinates).

The Expert Vibro device monitors the minimum air gap for critical values. The ProfiSignal software enables users to portray and evaluate the measurement data in trend diagrams.

Benefits of Inobalt products

• Compact, inexpensive monitoring systems for measuring generator air gaps
• Independently operating device with a 16 GB data logger capacity
• Universal inputs suited to air gap sensors
• Determination and monitoring of minimum values
• Connectivity to control systems via PROFIBUS-DP or digital outputs

Combustion chamber vibration

The efficiency of gas turbines is a primary factor for economic success. Every technological possibility must be exploited. This brings new challenges to the secure operation of gas turbines.

Monitoring is required not only of conventional vibration data from bearings and shafts, but also of dynamic pressure vibrations within combustion chambers. To achieve this, several (usually 2-3) high-temperature-resistant pressure sensors are installed within the combustion chamber. These sensors provide dynamic pressure vibrations that are then recorded by Inobalt Expert Vibro devices.

Pressure vibration data contains information that is relevant to machine security and analysis. The first step in analysing this data is to perform FFT-analysis on the pressure signal. An FFT spectrum enables users to determine and monitor narrow-band characteristic values. Expert Vibro devices immediately calculate the TRMS value for each frequency band. TRMS values undergo monitoring and in the event of an alarm, either messages are sent via PROFIBUS to a main control system, or switching occurs at digital outputs. Characteristic values and FFT spectrums are recorded to the Message device's internal data logger. The ProfiSignal software and Vibro option enable users to portray and evaluate measurement data in FFT or cascade diagrams.

Benefits of Inobalt products

• Compact, inexpensive monitoring systems for combustion chamber vibrations
• Independently operating device with a 16 GB data logger capacity
• Universal inputs suited to pressure sensors
• Computation of pressure and narrow-band characteristic values
• Computation of TRMS characteristic values
• Connectivity to control systems via PROFIBUS-DP or digital outputs

Mobile vibration measurement

Specialist firms have become established in the field of vibration measurement technology, who provide services for analysing and rectifying vibration problems.

Large companies use their own in-house technicians to perform the vibration servicing of their plant and machinery.

Vibration analysis requires the on-site acquisition of relevant data.

Inobalt's mobile measurement case enables users to acquire data from a wide range of different types of signal. Versions exist for virtually any type of connection. The typical types of sensor connection are Lemosa, BNC, Tuchel or customized connections.

ProfiSignal's Vibro option enables users to portray and evaluate raw vibration data, frequency spectrums and characteristic values.

Inobalt's mobile vibration-measurement case is intended for users who perform on-site machinery measurements either independently or with PC support. The measurement cases are designed to cope with tough environments and frequent relocations. They have an internal data storage capability to enable independent measurement over long periods of time.

Benefits of Inobalt products

• Compact mobile measurement case for tough environments
• Connectivity for virtually any type of vibration sensor
• FFT analysis and characteristic value computation integrated within the case system
• Monitoring of vibration levels
• Process and vibration measurement can be performed with a single case system
• Intelligent data logging within device
• Visualization and analysis using time signal, trend spectrum, FFT cascade and orbit diagrams