OK, let the electronics guy try to clean this up. I've been meaning to get around to this for a while, but kept putting it off.
Got a little pain thing going on, so probably not the best time, but what the heck.
Dielectric anything is electrically non-conductive. It also usually refers to its ability to store an electrostatic charge, but that is not important for this.
Dielectric grease is usually used where lubrication that will not conduct electricity is necessary.
Spark plug boots is the most common.
Heat sink grease or compound is thermally conductive. It conducts heat really well.
It is used between two objects that need to pass heat between them.
In most cases, having the objects actually touch firmly is the best.
But, since most surfaces are not perfectly smooth, a thin film of heat sink compound will fill the gaps that would otherwise be filled with poorly conducting air.
Here is where the trouble comes in.
A dielectric grease should not conduct electricity. It may or may not conduct heat well.
A heat sink compound should conduct heat well, it may or may not conduct electricity.
Most heat sink compounds will not conduct electricity, since they are often used on electronic components.
But, since their use is for heat transfer, you can't be sure.
Silicone grease is an excellent dielectric grease. And is the basis of many heat sink compounds.
Additional materials are added to increase heat transfer. Titanium dioxide is one of them, and is a nonconductor, so the resulting heat sink compound is a good dielectric grease.
But,some companies use colloidal silver, which can cause it to be conductive at higher voltages.
The big problem is that some companies and many people use the two terms interchangeably.
With a distributor module, the primary need is for removing heat. So, you want to be sure what you use is a heat sink compound.
But, since there is high voltage jumping around, dielectric properties are good too.
What to use? Well, if you do not have a known good alternative, use what came with the module.
Personally, since I do lots of electronics work, I have access to stuff that is probably better than what comes from discount auto houses.
But, my stuff has its heat transfer properties AND its dielectric properties listed, so I know what I am dealing with.
The important thing is to not put it on too thick. Anywhere the surfaces can touch, you want them touching with no compound between them. Heat sink compound cannot increase the transfer of two clean surfaces actually touching, it can only break even or usually make it worse.
But it must fill any gaps to keep out the air.
So, heat sink compound may be dielectric or not, dielectric may be heat sinking or not, or either one can be both.
See how simple it is.................
