Lubrication Questions Flashcards
In a bearing the rolling surfaces should not run dry. As a general rule for lubrication, how far up the lowest rolling element should the oil level be? And why?
Oil level should be between one-third and one-half of the way up the lowest rolling element. If the oil level is too high, the rolling elements churn the oil and generate excessive heat.
What is the maximum speed of a journal when being lubricated by a bottle lubrication system?
Low surface speeds of 250feet/min.
Name one advantage and disadvantage of a bottle lubrication system:
- Advantage – Oil is always visible
- Disadvantage – Oil is wasted instead of circulated
What is one of the oldest methods of applying oil?
Wick feed oiler is one of the oldest methods of applying oil.
Constant level cup lubrication requires the bottle to be mounted on a specific side of a bearing housing. What side would you mount it on?
Constant level cup should me mounted on the side of the machine that is in the direction of rotation. If the machine rotates in a clockwise direction, mount the bottle on the left side. If the machine rotates in a counterclockwise direction, mount the bottle on the right side.
At what speed should you not go past when using a Drip feed lubricator?
Maximum speed of 3600 rpm
Ring or chain oilers can lubricate at speeds up too 3600rpm. When changing the bearings in this set up, what should you also inspect at the same time? Why?
When changing bearings, always inspect the ring or chain oiler for wear and replace it if there is any noticeable thinning of the material. Failure of these oilers quickly leads to bearing failure.
Pressure lubricated systems recycle oil through a filter, give an example of where you would use this set-up? Also at what temperature would you want to add a heat exchanger to the system?
- Applications o Engines o Gas turbines o Steam turbines o Large reciprocating compressors o Medium and large vane compressors o Centrifugal compressors - The heat exchanger controls the temperature of the oil if it is exposed to temperatures above 55 degrees Celsius.
What is the result if oil/filter is not changed periodically or to manufactures recommendation?
Filter can become severely clogged, reducing the volume of oil passing through the filter.
Name three types of fittings found on an Air-Activated lubrication system and one application for each:
- Spray fitting
- Condensing fitting
- Mist fitting
What pressure would you set the compressed air to for the oil to atomize?
10 to 50 psi
Air-oil lubrication system has one main advantage over an oil mist system in terms of safety. What is it? Also name one disadvantage to this set-up.
- Air-oil systems deposit fine droplets of oil on bearings without creating a potentially dangerous aerosol.
Disadvantage of air-oil lubrication system – Expensive, requires several oil lines, potential for fretting corrosion on the shafts
Why must you make sure the supply oil for a block lube system is clean and free of grit?
Heavy particles and floating debris can clog up several components in the block lubrication system and interrupt flow of oil.
Oil Analysis is an important part of preventative maintenance. Name four things this tells us about the oil in a system:
- Oil analysis provides silicone concentration in oil which can indicate seal wear and prevent leakage.
- Metal found in oil can identify which components are wearing and how fast.
- A change in viscosity indicates the oil is contaminated or has oxidized.
- Oil analysis checks for total acid number and total base number, a rise in TAN and/or drop in TBN generally indicate increasing oxidation and may also be related to depletion of an additive. The TAN and TBN numbers can be your guide to oil quality problems and the need for filter or oil changes.
In an oil analysis, it shows contaminants in the oil. How is this measured? What would you want to compare this reading to?
Particle count gives number of particles per milliliter for each of the following particle sizes: 2, 5 and 15 microns. The results are given in ISO range numbers which can be checked against cleanliness target levels established by the manufacturer.
Why would you take an oil sample right after the machine has been running?
Samples should be taken immediately after the machine has been running at its normal operating temperature for correct oil analysis. When machine in not running, any debris in oil settle to the bottom. These materials need to be circulating for correct oil analysis.
What are the two safety considerations to keep in mind when you handle or store lubricants?
Cancer and fire.
What position would you have the openings of a drum of oil face when storing and why?
Openings should be at 3 and 9 o’clock, covered on the inside with the lubricant to prevent dirt and water from being drawn in whenever there is a temperature drop.
Is it ok to use new oil straight from the drum on sensitive equipment? Why?I
New oil does not meet the cleanliness target for sensitive equipment.
Excessively high heat could potentially break down the oil. Name three things that could happen in this case:
- Oxidation
- Separation
- Evaporation of water from fire-resistant fluid
