The Data Acquisition & Analysis Program
Generatortech provides a Windows-based program that combines data acquisition with the display and analysis of rotor shorted turns. The system uses a high-speed, 32-bit data acquisition board to record the flux probe waveforms. The program provides an oscilloscope-like display while recording the data. The waveform can be analyzed immediately with Generatortech's software. The program automatically identifies and labels the waveform features and measures the appropriate values to provide accurate estimates of turn shorts in each coil.
Ease of use was the most important guiding principle behind the design of the program. The program has two automatic recording modes that eliminate the need to man the equipment during testing periods. The hardware takes between 10-15 minutes to setup. The Generatortech program is then started before a unit startup or shutdown (or before a large load swing). The program will automatically record all the required waveforms to help optimize sensitivity to detect all true turn shorts and to eliminate the reporting of false turn short indications.
In addition, all user settings are saved when exiting the program and are reloaded when the program is restarted. Therefore, after the initial setup, the process of acquiring and saving data is reduced to a few simple steps.
Below are sample graphs showing the variety of displays available when analyzing waveform data.
Raw Flux Probe Graph - shows the raw data recorded from the flux probe at a low load. This is a 2-pole rotor with 6 coils/pole and 18 turns in Coil 1 and 20 turns in Coils 2-6.
Analysis Graph - shows a little over one cycle of raw data (red) with the flux density curve (dotted blue) overlaid. The flux density zero-crossing (FDZC) position is marked with a green vertical line in graphs other than the Raw Data Graph.
All Slots Overlay Graph - shows an overlay graph with leading and lagging coil slots. For a generator, the FDZC position is always in the leading slot region, thus, lead slot data is much more sensitive.
Lead Slots Overlay Graph - shows an overlay of the each pole’s leading slots. The single short in Coil 5-Pole A (20 total turns) is clearly displayed at this load whose FDZC position is well aligned with Coil 5.
Summery Sheet Printout - shows four graphs, plus the Shorted Turn Data Table.
