I've resently had two gearbox failures on philadelphia 3807 gearboxes. One failure was output bearing failure about 30rpm. The other gearbox failure was an output pinion gear. I didn't see any spectrum analysis to indicate a problem before the failures occured. I'm running the route frequency (vibration data collection) every 180 days. Am i missing too much having the route frequency at this high of a span.

Hi there,
Looking at your posts as a pair, I think you are not doing high frequency measurements at each bearing and not frequently enough.

That's why you are missing the failure signs.

We always do Velocity and Impulse demodulation to 100x shaft speed at the measurement point,and wide band acceleration 0-10,000 Hz.

You need to do the measurements more often than the time you think the bearing can go from good to bad condition.

Despite all this I have missed several failures, so don't feel to badly about it.

Cheers

John