Vibration monitoring unit AIRGAP

Large, low-speed hydro generators have a very small ratio between the stator bore diameter and the air gap, which makes it impossible to center the elements perfectly during the assembly process. As a result, the machines operate with a small but relevant misalignment. Faults on the poles can lead to a considerable unbalance of the magnetic attraction forces, which also leads to significant misalignment, vibration, and additional losses. It is therefore important to assess the following parameters: misalignment; minimum and maximum air gaps; stator and rotor shape; magnetic flux of each pole; and, above all, to check the machine’s mechanical trend, to ensure safe operation and avoid serious damage. Rotor-to-stator rub Pole mechanical instability Loss of operating efficiency Magnetic unbalance Thermal hotspots Depending on the stator size, between 4 to 16 airgap sensors installed uniformly around the stator core MPS: Minimum gap per revolution CMS: Pole profile, stator shape, rotor shape, stator and rotor center position, minimum gap position, pole stability Gearmills millsdrive Windturbines Hydrogenerators Airgap transducers