New to oil analysis I'm getting a chemistry that says dielectric increase. Just wondering if any info was out there that could help me out.

What type of machine are we talking about? IMO it's a bit odd since dielectric properties should, in any case, decrease as the oil impregantes with contaminats such as water or metallic particles.

Could you post the lab results? Are you 100% sure the sample was correctly taken?

Also, did you take a sample of unused oil for comparisons?

It is a CSI 5200 mini oil lab. I do run a reference oil. It says it indicates free water on some of them. It also says check oil color.

Here is a link to a good explanation:
http://www.practicingoilanalysis.com/article_detail.asp?articleid=226

Our TMEH 1 Oil Analzer measures dielectric constant. Dielectric change is directly related to contamination and degradation of the oil.

Regards,
Dave G.

Good article, Dave

I apologize Albert. The info I posted above was wrong. As the article states, when there is contamination or degradation of the oil (e.g. oxidation) the dielectric value WILL increase.

You should check the viscosity and basic number, to see how bad your oil has turned.

I hope no harm has been done.

Cheers

The original post was not specific about what kind of dielectric parameter was being tested.

There are two dielectric parameters we can test:
1 - "Dielectric constant" - this is what is referred to in the link above. It is a unitless number (symbol epsilon with subsript r for relative permeability) in the range of maybe 2 - 5 for most insulating materials.

2 - "Dielectric breakdown" - this is more commonly tested in transformers. It is expressed as a voltage, typically in the range 30kv - 45kv. Low values indicate contamination or degradation of the oil.

At the time mechanical pawn first answered, we didn't know which parameter it was. And his initial answer was correct for dielectric strength. So no need to apologize

I googled CSI minilab and it does in fact measure dielectric constant as discussed by Dave G.

Hello All,

CSI 5200 measures Dielectric Constant.

Very often we see reduction in dielectric constant value of used oil compared to reference oil (new oil). We use CSI 5200 as well. Any possible reason for this?

Thanks

Maha

I'm now having trouble on yet another thing. When I go take an oil sample out of a gearbox it may show Wear and no contamination. I go back the same day and take it again and it shows contamination and no wear. I'm having this problem alot and any help will be appreciated.

I'm not sure exactly what you mean by wear (direct reading ferrography?) and contamination (ISO cleanliness / particle-count?).

I can tell you we observe a lot of variability in the ISO cleanliness / particle-count and I believe it is well recognized in the industry that normal ASTM particle count test method (based on counting things that block light) can be very variable and fooled by things like water and oil oxidation products (very early stages of sludge). There are a slew of methods and some are better than others... about the limit of my knowledge.

And of course, cleanliness and DRF tests would both be be sensitive to sample location (representative sample), flushing, etc.

Hi Albert,

It might be useful to check your sampling method. We have installed sampling valve in most of our equipments and are able to get very consistent results.

If you are using CSI 5200, you can verify Wear by making a Patch test and use microscope to view it.

Hope this helps

Maha

I'm still having trouble when I go get an oil sample I can run the oil and it show Wear or contamination or both and I can run another sample out of the same bottle of oil and it show to be fine. Remember I am new to this and I've had no training. People are starting to ask questions and I really do not know what to say. Almost every gear box I pull a sample on shows either wear or contamintation and I no the oil is not bad because it has just been replaced and the gearbox has been flushed. Another question is what do you recomend flushing the gearboxes with?