Abstract: A method and device for determining the occurrence of rotating stall in the turbine blade of a compressor, in which the blade pass frequency of at least one compressor stage and the associated vibration energy are monitored, the normal blade pass frequency being constituted by the operating speed of rotation of the compressor multiplied by the number of turbine blades in the stage, and in which incipient rotating stall in a compressor stage is indicated when, at the normal blade pass frequency of the compressor stage, the vibration energy falls below a predetermined first value at the same time as, at a blade pass frequency above the normal blade pass frequency, the vibration energy rises above a predetermined second value.

Abstract: A method for determining the condition of a turbine blade (2, 4) in a compressor and utilizing the collected information in an estimation of the lifetime of the turbine blade (2, 4), whereby a measured value reflecting the condition of the turbine blade (2, 4) is generated by a vibration sensitive sensor (10) connected to the compressor's (1) casing (6).

Abstract: A method and device for determining the occurrence of rotating stall in the turbine blade of a compressor, in which the blade pass frequency of at least one compressor stage and the associated vibration energy are monitored, the normal blade pass frequency being constituted by the operating speed of rotation of the compressor multiplied by the number of turbine blades in the stage, and in which incipient rotating stall in a compressor stage is indicated when, at the normal blade pass frequency of the compressor stage, the vibration energy falls below a predetermined first value at the same time as, at a blade pass frequency above the normal blade pass frequency, the vibration energy rises above a predetermined second value.