Capacitive air gap sensor CS25

non-contactfor generators and alternators

 25 mm measurement range  Non contact measurement of static or dynamic surfaces  Robust sensor arrangement with integral dual coaxial cable  Driver unit with multiple output options  Dynamic, Pole Profile and Minimum Gap outputs  Probe operating temperature range -20 °C to +125 °C Air Gap monitoring of hydro electric generators is a critical measurement requirement driven by the need to understand the dynamic relationship between the rotor and stator in power generation applications. On large hydro electric plant the rotor to stator air gap can be used to monitor both the eccentricity of the rotor relative to the stator and individual pole to stator air gaps. Centrifugal and magnetic forces, in addition to changes in temperature, have a direct impact on the eccentricity and hence the efficiency of the generator. Individual pole gap analysis also provides important rotor condition monitoring data which can be utilised to schedule maintenance and extend the life of older plant minimising downtime for inspection and refurbishment. The early detection of rotor / stator rubs allows the generator to be shutdown prior to the onset of permanent damage. The CS25 air gap sensor from Sensonics is a non-contact dynamic position transducer utilising a capacitive technique to provide an accurate displacement measurement from the sensor face to a metal target. The advantage of the capacitive technique in generator applications is the high immunity to magnetic fields; the CS25 also provides high resolution and relative insensitivity to different (metal) target materials.