Proximity probes

[tmoritz]

I am currently responsible for specifying portable machine testing and monitoring equipment for use on 14 small hydroelectric generators. All the units are vertical francis units with three fluid film guide bearings and a single thrust bearing. These are low speed units with the fastest unit spinning at 480CPM. The turbine and rotor shafts are forged carbon steel.

My question for this discussion group is what type of proximity probe, eddy current, capacitive, or inductive, is best suited for measuring shaft motion relative to the bearings? I will be using this equipment to record base line values (orbit, shaft centerline, vibration signitures, etc.), periodically monitor each unit under normal operating conditions, complete pre-teardown readings taken over a range of unit loads, post-overhaul readings to confirm unit condition, and evaluate bearing dynamics when unit conditions indicate there's a potential problem.

Thank you in advance,



Tom Moritz
Mechanical Engineer
US Bureau of Reclamation

 

[sms]

It really depends on how much range you need. A typical eddy current probe has a rang of 100 mils, with an extended range probe having maybe 150 mils. If you need more range you would need a different probe type.

What is the bearing diametral clearence?

-The future's so bright I gotta wear shades!

 

[dgallagher]

This is a simple application that we commonly monitor. Please contact me via e-mail or phone - contact information is at website on my signiture and I'll discuss offline a cost effective proximity probe monitoring solution.