The vibration sensors used in turbine, generator etc are allsame type i.e proximity type of sensors.
The sensor aremounted at the proximity of the Turbine and generator rotor.
From the sensors one coaxial cable runs to the proximater,which is mounted in a separate JB nearby.
From TSI Monitors, this Vibration probes gets +24 Volts DC.
The proximater gives a signal 0 to -22.4 Volts DC depending upon the vibration measured by the sensor.
Generally the distance
between the probe tip and the rotor is maintained such that it gives -10 Volts DC when the turbine is not running.
The sensor works on eddy current principle. As the rotor vibration increases, the eddy current generation remains constant, but the absorption of power in terms of eddy current increases.
This loss of power is sensed by the proximater and DC voltage signal is transmitter to TSI monitor.