More than yet another design house
More than yet another design house
Torsional Vibration Monitoring System (TVMS) is monitoring system capable to measure shaft torsional vibration and evaluate instantaneous angular velocity and displacement. Measurement of shaft torsional vibrations is based on evaluation of TOAs (Time Of Arrival) which are detected times of encoder marks. TVMS is standardly used with optical or electromagnetic probes. Voltage level of optical probe output signal is proportional to reflectivity of area focused by light beam of the probe. For the optical measurement, the zebra tape with alternating black and white stripes is used. The electromagnetic sensor uses mostly toothed gears installed on the rotor.
TVMS unit is used to measure and threshold the probe output signal. Detection times of zebra tape stripes or teeth of toothed gear are stored in database (DB) and further used for evaluation of rotor instantaneous angular velocity and displacement. Software application VMS Setup is used for setup of the TVMS unit.
Fluctuations of generator air-gap torque, caused by non-stationary conditions of electrical power grid, influence shaft torsional vibrations. Symptoms of shaft torsional vibrations are not measurable by standard sensor instrumentation, so special measurement should be installed.
The direct consequence of shaft torsional vibrations is local acceleration or deceleration of shaft circumference when it is measured by a stationary sensor. Torsional vibrations of a turbine-generator train manifest themselves as oscillatory relative angular displacements of distinct sections of the rotor. Due to the torsional deformation, material stress occurs which, in the most unfavourable scenario, causes shaft cracking. Additionally, torsionally-induced blade vibration proves to be a source of blade root cracking, presenting a severe threat to the safety operation of the machine.
| Parameter | Value |
|---|---|
| Sampling frequency per channel | 100 MHz |
| Resolution | 12 bit |
| Embedded PC | Yes (industrial grade) |
| Number of channels | 4 |
| Watchdog relay | Yes |
| Current loops | Yes |
EN - VMS-1002 flyer
Torsional Vibration Monitoring System (TVMS) is monitoring system capable to measure shaft torsional vibration and evaluate instantaneous angular velocity and displacement. Measurement of shaft torsional vibrations is based on evaluation of TOAs (Time Of Arrival) which are detected times of encoder marks. TVMS is standardly used with optical or electromagnetic probes. Voltage level of optical probe output signal is proportional to reflectivity of area focused by light beam of the probe. For the optical measurement, the zebra tape with alternating black and white stripes is used. The electromagnetic sensor uses mostly toothed gears installed on the rotor.
TVMS unit is used to measure and threshold the probe output signal. Detection times of zebra tape stripes or teeth of toothed gear are stored in database (DB) and further used for evaluation of rotor instantaneous angular velocity and displacement. Software application VMS Setup is used for setup of the TVMS unit.
Fluctuations of generator air-gap torque, caused by non-stationary conditions of electrical power grid, influence shaft torsional vibrations. Symptoms of shaft torsional vibrations are not measurable by standard sensor instrumentation, so special measurement should be installed.
The direct consequence of shaft torsional vibrations is local acceleration or deceleration of shaft circumference when it is measured by a stationary sensor. Torsional vibrations of a turbine-generator train manifest themselves as oscillatory relative angular displacements of distinct sections of the rotor. Due to the torsional deformation, material stress occurs which, in the most unfavourable scenario, causes shaft cracking. Additionally, torsionally-induced blade vibration proves to be a source of blade root cracking, presenting a severe threat to the safety operation of the machine.
| Parameter | Value |
|---|---|
| Sampling frequency per channel | 100 MHz |
| Resolution | 12 bit |
| Embedded PC | Yes (industrial grade) |
| Number of channels | 4 |
| Watchdog relay | Yes |
| Current loops | Yes |
EN - VMS-1002 flyer