Do all oils lubricate?

[Loobed]

I wasn't sure where to post this question.

I was wondering if all oils lubricate, or reduce the amount of friction between two parts. I have noticed that thicker oils and grease gives the appearance that friction is increased on very light parts, but those oils and greases must reduce friction under heavy loads otherwise they wouldn't be used.

One time I experimented with different types of oil for machining parts on a lathe and I found that a transformer cooling oil was worse than no oil at all. I know there are many different kinds of oils. Do they all have lubrication properties, or do some increase friction?

 

[Quest]

transformer oil serves 2 functions that fundamentally differ from the basic lubrication properties of lubricant oil:

(1) cooling

(2) dielectric properties (or, depending on application, can be blended for much higher electrical insulation properties).

With those 2 requirements in mind (an no moving parts within a high power transformer to lubricate to begin with), I'd say that transformer oil is not for lubrication, period.

Q.

 

[JimPghPA]

I once read of one of the initial searches NASA was doing when designing something and looking for an oil. They found a listing of a very high temperature oil, and ordered some. When it arrived it was a powder packed in a paper package. They called the manufacturer, and were told that below a certain temperature that oil is a solid.

So along with your example of transformer coolant, some are designed for specific areas of application, such as very high temperature, and may have inappropriate physical characteristics when used outside of intended area of application.

 

[Tempest]

Transformer oil is not made from typical oils:
http://en.wikipedia.org/wiki/Transformer_oil

I think part of your confusion comes from conflating terms.

A "heavier" oil is typically defined as a more viscous oil. Viscosity is (in simple terms) the resistance to flow of a fluid. If you put something in a more viscous oil it will be harder to push around. This same principle is why more viscous fluids are used under higher localized loads...the oil doesn't move out of the way as easy and it is more likely to stay between the parts under load.

Also, not all "oils" have the same lubricating properties, especially under load. This is why silicone "oil" is not typically used for metal on metal conditions. It doesn't "push back" (increase in viscosity as it is squished) as much as other types of oils do.

I can't imagine any liquid not reducing friction to some degree, unless you have a situation like water between 2 pieces of glass.

It is possible that oil might react with the cutting material or burn at the cutting zone and make things worse.

 

[djb]

Originally Posted By: Tempest
Transformer oil is not made from typical oils:
http://en.wikipedia.org/wiki/Transformer_oil


As the Wikipedia article correctly notes, transformer oil is primarily mineral oil. Carefully refined, and with a bunch of additives, but mostly common mineral oil.

Other cooling applications for electrical and electronic equipment use plain refined mineral oil with no additives. The oil needs to be non-toxic so that the equipment can be easily serviced. You wouldn't want a simple mistake to shut down an office for an extensive clean-up.

I would expect transformer oil to work OK as a lubricating oil in an undemanding application.

 

[Stelth]

Also, not all lubrication is the same. I can tell you from experience that motor oil makes a lousy thread-cutting lubricant, but sulfur-lard based cutting oil works really well.

 

[Shannow]

Transformer oil is a great lubricant.

I've seen bearings run in transformer oil run for 20+ years for 8,000 hours per year, and not have any wear related issues.

Throw it in your engine or your fuel tank (have seen both), and stuff will fail badly.

Big transformers have circulating oil systems to force the convective cooling.

These systems have submerged (in transformer oil) motor/pump sets, that are cooled and lubricated by transformer oil.

The bearings are designed that they are hydrodynamically lubricated by the oil, at the temperatures, clearances, and RPM appropriate for the pump.

That same oil has proved useless on a lathe...

yep

lubrication design is a circular argument. oil begets design, begets oil...

 

[MolaKule]

Quote:
I was wondering if all oils lubricate, or reduce the amount of friction between two parts.


What exactly is your question? From all of the discussions and data presented here on this website this question just seems, well, interesting.

All oils lubricate and reduce friction. But that is not the whole story. You also have to have a performance package to increase the total oil's performance. Different oils and of different viscosities and different additive packages are used in each application.

Greases have oils in them but are thick in order to stay in place. Some greases have tackifiers in them in order to stick to parts so the oil or grease will not get slung off.

Quote:
One time I experimented with different types of oil for machining parts on a lathe and I found that a transformer cooling oil was worse than no oil at all.


My point exactyy.

I don't know what kind of transformer oil you used, but most transformer oils (or cooling oils, heat transfer oils) used in the smaller transformers is simply a mineral oil or blend or synthetic base oil wih two additives, those addtives being an anti-oxidant and anti-foam.

Please do a search on the Stribeck curve.

 

[MolaKule]

Also see

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=729336#Post729336

this link about Greases.

 

[MolaKule]

And

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=729025#Post729025

 

[HerrStig]

Transformer oil, and the oil used as a diaelectric in capacitors of a certain type, used to contain PCBs, pretty nasty stuff. Pyrenol was one of the trade names.

 

[bruce381]

world wide most transformer or insulating oils are low vis with low PP in the USA that is napthenic. AO and metal inhibitors are used to offer longer oil and component life in use.

 

[Shannow]

Originally Posted By: Quest
transformer oil serves 2 functions that fundamentally differ from the basic lubrication properties of lubricant oil:

(1) cooling

(2) dielectric properties (or, depending on application, can be blended for much higher electrical insulation properties).

With those 2 requirements in mind (an no moving parts within a high power transformer to lubricate to begin with), I'd say that transformer oil is not for lubrication, period.

Q.


The ones that I'm familiar with have some fairly decent examples of moving parts

 

[bruce381]

yeah built in pumps for cooling and oil circulation

 

[camelCase]

As MolaKule said, transformer oil is typically just base stock mineral oil with a low amount of additives for anti-foam, dielectric performance, etc. Pretty much the same oil used in oil emerged computers and EDM machines.


Cutting fluids actually have a large amount of EP additives. Like someone mentioned, the very sulfurous lard based ones are a great example. Sulfur is an awesome EP agent. All cutting fluids have EP and antiwear agents in them - transformer oil does not.