Part 56 - Oil Varnish in rotating equipment
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- Опубликовано: 5 фев 2025
- About the presenter:
• Recipient of the ASME Burt L. Newkirk Award.
• Recipient of the ASME Turbo Expo Best Paper Award (Structures and Dynamics Committee).
• Recipient of the Best Paper Award from International Rotor Dynamics Conference - IFToMM.
• Recipient of the ASME IGTI Young Engineer Award.
• Ph.D.
• American (US citizen)
• Email: rotordynamics101@gmail.com
• LinkedIn: / rotordynamics
• Twitter: / rotordynamics1
It was great video .. !!
In case of natural cooled bearings where oil is not flown outside from lubrication oil system how to monitor or find out oil degradation.
Thank you! I’m glad you enjoyed the video!
For naturally cooled bearings where the oil stays within the system and doesn’t circulate externally, monitoring oil degradation can be a bit tricky, but there are a few reliable approaches:
1. Temperature Monitoring - Keep an eye on bearing temperatures. A gradual rise in temperature can indicate oil degradation or varnish buildup.
2. Vibration Analysis - Changes in vibration patterns can signal lubrication issues. Degraded oil often leads to higher friction and wear, which reflects in vibration data.
3. Acoustic Emissions - Listen for unusual noises. Degraded oil may reduce the lubricating film, causing bearings to produce more noise during operation.
4. Regular Oil Sampling - If possible, extract small amounts of oil periodically to test for oxidation levels, Total Acid Number (TAN), or contamination. This gives a direct insight into the oil’s condition.
5. Filter Inspection - If the system has any inline filters, inspecting them for residue or varnish buildup can provide clues about the oil's condition.
Let me know if you need more details on any of these methods!
great video
Thank you! I'm glad you liked the video!
Good information regarding varnish. I would like to add two more points here : Some of the varnish related problems that are arising today are due to switching of oil from group I base stock to group II base stock as the later has lower solvency than the former due to higher purity , it also involves oil replacement procedure because the varnish / coked residue of group I when left untreated in the system can cause problem at later stage when mixed with group II. However it does not mean that group I base stock is superior to group II & II in terms of varnish or oxidation resistance ,in fact it’s the opposite. The only drawback comes in the form of conductivity where base II & III have lower conductivity compared to group I due to its higher purity but that is being managed with additive supplement in case specific turbo machine oils.
Thank you for sharing your insights! You're absolutely right - the transition from Group I to Group II base stocks and the associated solvency differences play a critical role in varnish-related issues. I didn’t cover that aspect in this video to keep it concise, but I’m planning to address it in a follow-up video dedicated to oil base stock transitions and their impact on varnish formation. I appreciate your detailed comment - it adds great value for viewers!
Good video... What is FZG @3:48 of this video?
Thanks.
Great questions. FZG refers to a gear scuffing test method developed at the Forschungsstelle für Zahnräder und Getriebebau (FZG) in Germany. It is commonly used to evaluate the load-carrying capacity and scuffing resistance of lubricating oils, particularly for gear applications.
In your case:
FZG = 9: This indicates the scuffing load stage in the FZG test. A rating of 9 means the lubricant can handle moderate to high levels of gear contact stress before failure.
PRT (or Part Running Time) = 1700 hours: Refers to the total operational hours of the lubricant in service.
VVRT (or Variable Viscosity Running Time) = 456 hours: Refers to the time under varying viscosity conditions, such as high-temperature or high-load operations.
@@RotorDynamics Appreciate for such a detailed explanation!
Thanks for sparing your valuable time.
@ You're very welcome! Glad I could help.
How do you know if the varnish is caused by electrostatic discharges?
Great question! Varnish caused by electrostatic discharges typically results from the buildup of electrical charges on surfaces, leading to localized heating and breakdown of insulation materials.
Signs include discoloration, unusual wear patterns, or degradation of insulation around (near) electrical components.
It can be confirmed through testing, such as conduct oil analysis to check for byproducts of ESD, such as specific contaminants or degradation products. And, also inspecting for arcing marks. Would you like more details on detecting this? :)
@RotorDynamics that's cool thanks! Yes, I would like to know more if there is a video
Thanks
What's different between varnish & scale & deposit & sludge?
Sure! Here’s a simple breakdown:
1. Varnish - This is a thin, sticky coating that forms when oil breaks down, usually from high heat or oxidation. It can build up on surfaces and affect performance.
2. Scale - Scale is more like a hard, crusty layer, often from minerals left behind by water or heat. You’ll see this in boilers or pipes.
3. Deposit - This is a general term for any material that settles or builds up on machine parts - could be from oil breakdown, dirt, or contaminants.
4. Sludge - Sludge is thick and soft, more like a goo that collects at the bottom of tanks or sumps. It’s usually from oil degradation mixed with contaminants.
I hope that helps! Let me know if you’d like to dive deeper into any of these.