CTRL Systems, Inc. worked with a windmill installation in Canada to test high frequency ultrasound sensors for slow speed bearings. A total of 9 windmills were tested by CTRL. The rotational speed of the bearings was typically 15-20 rpms during the recording process.
An initial review of the data shows the clear presence of ultrasound at 40 kHz is produced by the bearings. The characteristics of the ultrasound was similar for each windmill tested. Some windmills produced slightly higher amplitude signals.
It is determined that CTRL's ultrasound detectors are capable to be used for slow speed bearings with confidence. The signal-to-noise ratio and sensitivity is sufficient to capture meaningful data. The data can be trended and analyzed to determine the condition of the slow speed bearings. These tests demonstrated the proof of principle. CTRL looks forward to future tests for the integration of ultrasound for slow speed bearings in different conditions.