Sorry, I got unexpectedly called out of town on a work related issue. I just love it when a customer calls and tells us we have a problem, only to find a forklift speared the equipment and damaged it. Somehow that's our problem. And if you want to see the effects of the government shutdown try going thru TSA security. Talk about some testy people, and then you get the TSA agents...NOT a fun time for air travel.
Originally Posted by
pdlamb
How do contacts fret? Doesn't fretting require small repetitive mechanical motions? Electrical contacts on my bike stay connected for months or years at a time.
The pin & socket designs on most electrical contacts DO move relative to each other when they are mated due to vibration, stress on the wires, temperature variation, etc. Depending on the contact's surface finish and lubrication fretting will eventually happen. Contacts like Anderson Power Poles that use spring force to hold two overlapping contacts together are actually much worse for fretting, but their contact design anticipates this and the finish of the contacts minimizes the effect. Lubrication still helps.
I have it on every contact on the bikes, staying there for ages. Without the grease the contacts that are not golden usually go south pretty quick, at least on my bikes.
If by "golden" you mean an actual gold finish, yes, I would not expect to see any issues with fretting. Gold is one of the only contact materials that typically won't fret in electrical contacts due to its self lubricating properties.
Originally Posted by
unterhausen
I have used dielectric grease on car connectors, seems like a good idea. It's commonly used on cars and I always buy it at auto parts stores. It seems pretty inert, never seen a problem due to using it.
On a bike I wouldn't expect too many issues with dielectric grease on electrical contacts, but on vehicles I have reservations. Dielectric grease is typically silicone oil in a soap base to thicken it. The silicone oil will soften the silicone seals used on most electrical connectors, reducing the effectiveness of the seals. I've seen dielectric grease soften the nylon connector body, allowing the electrical contacts to get pushed out of the connector body and cause issues. When used on contacts the silicone will migrate out from the oil and/or evaporate, leaving behind the soap base. The soap base becomes sticky, and in many of the cheap dielectric greases can actually become abrasive to the finish of the electrical contacts, causing them to fail in use. I'd actually use petroleum jelly on contacts before I'd use dielectric grease.
The grease is really just making the contact gas-tight. It fills the gaps between the mating surfaces and prevents any gases like water vapor from getting in. ANYTHING that is soft enough but will allow the contacts to make surface to surface contact will work and, if the material will not migrate or wash out, will prevent deterioration of the contacts due to moisture. If that same material can also lubricate the contacts it will help prevent fretting damage. In my experience (30+ years engineering connection systems) NyoGel 760G is the best product out for electrical connections. Dielectric grease is pretty much near the bottom of the list (just above butter,) but is the most commonly specified due to its availability. It falls into the category of "it's better than nothing" but often nothing is better.