On 8/8/15 8:24 AM, Stormin Mormon wrote:
On 8/7/2015 10:24 PM, J Burns wrote:

Oil draws moisture from the air. I wonder if that's true of all oils.

No, just detergent oils. Didn't you hear the
old saying "oil and water don't mix" ??? To
mix oil and water requires detergent.

http://reliabilityweb.com/index.php/..._oil_and_water

Unfortunately, this disagrees with you. All oil absorbs water.

Fortunately, this agrees with you. Detergents make oil absorb a lot
more water.

Unfortunately, this disagrees with you. Having water in the oil is fine.
It's when it comes out of the oil that it damages bearings.

Valvoline advertises the demulsibility of its compressor oil. In a
factory, you want water in the oil to demulsify and settle in the sump
so a watchful engineer can drain it.

By definition, detergent increases emulsibility. I think I see why motor
oil has detergents. There is no engineer watching the sump. In winter,
maybe water could accumulate to the point that the oil pump would pick
it up and send it to the bearings. So they put detergent in the oil to
be sure water stays in the oil.

In an electric motor, the water in the oil will depend on the humidity,
but it shouldn't end up on the bearings, whether the oil is HD or ND.
Water in oil can speed deterioration of the oil. That's what additives
are for.