Worn Ball Bearing
Taken with the VPE-2000; Listen closely, you can actually hear the "chattering" ball defect.
Ultrasound from the motor side bearing of a high-speed overhung cantilever fan. The sound is barely audible.
Bad Gear Tooth
The bad teeth in this gearbox sound almost like a "pop" as they make contact. Otherwise it has a smooth healthy sound. The gear cracked shortly after these readings were taken.
This trace shows the fan side bearing, approximately one foot away, on the same fan. The excessive ultrasound was due to a bent fan shaft.
Air Leak with VPX-WR
Here is an example of "DND" at work. This air leak was recorded with the VPX-WR with a noisy compressor in the background. Listen to how the background noise is reduced and how the screaming leak sound dominates the signal.
This is a low speed gearset (38 RPM) in a enclosed gearbox for a conveyor drive. The sound was even and regular, indicating good performance.
Air Leak With VPE-2000
This is the same leak as you heard above recorded with the VPE-2000. This unit uses a traditional heterodyne translation.
This is a gearset in the adjacent conveyor in the same service. The gears are showing excessive interference which will lead to accelerated wear.