Condition Monitoring

[mikeprior]

I am currently investigating the merits and advantages / disadvantages of installing one or two sensors per bearing. We have 32 large bearings to measure vibration on and must decide if we are going to install one or two vibration sensors to each bearing. We plan on using the 9200AT for temperature and vibration measurement. From what i have experienced in the past, one sensor can suffice due to the fact that when a radial bearing is starting to fail, it will emit small amplitude vibrations in a radial pattern which can be detected by a sensor placed in any radial location around the bearing. So why have two sensors, (X & Y) per bearing ? What is the advantage of having two sensors when one sensor will be capable of measuring what you are looking for ? (great for the sensor manufacturers and vendors)

[tyagi]

Mike,

Using two probes indifferent direction will help in complete diagnostic of rotating system. two probes along witha phasor will give the complete advisory about the system that you can get in form of shaft centerline, orbit & bode plots. Instead of all these facts there is good document that will clear your doubts. Pls go through with that... 

Message Edited by tyagi on 09-10-2009 04:04 AM

[rrs_dave]

Probes and transducers are two completely different animals. You will not get a true "orbit", etc. with a transducer that you would with a shaft probe.

For what you are doing, it is probably not worth the expense of going to two transducers vs. 1, especially if you can get to the bearings and do some analysis if one of them starts trending up. You can get all the readings you need then.

Dave

[pc]

For rolling element bearings one sensor is fine. Insure to mount it in the least stiff direction.