Often, “plant floor” realities can create a problem when planning shutdowns because sometimes power transmission components like sprockets, idler rolls, sheaves, timing belt wheels, couplings, etc. can’t be inspected properly without shutting down an entire process. In such cases, there are times when a simple “visual” inspection would be enough to reveal the need to order a new part and have it ready. If this might be the case for you, take along a good strobe light, and if you can get close enough safely, “freeze” the coupling, sheave, sprocket, or whatever the component, while in motion to get a good look at it. By carefully varying the strobe timing, you can cause a component that is spinning at 3600 RPM to rotate at any speed you like (say a half RPM) and inspect all of it—every tooth of the gear, every part of the belt or sheave. If flaws are obvious, you may have just saved your company some downtime, not to mention a potential catastrophic failure!
CAUTION! Remember that with strobe lights the eye is deceived into believing that something is not moving, or moving very slowly, when in fact it is moving very fast. Do not ever forget this and NEVER reach out to touch the part you are inspecting!
Condition Monitoring, Maintenance Tips by Mike Fitch CRL