My thoughts are not expert, I don't know much about electrical motors, but for what it's woth: There has to be something better than petroleum jelly. I'm going to look up what the large tub of grease they use at the bike shop here. Its' a kind of general grease really not made for bicycles, but it's just a fraction of the cost in large buckets. It looks very much like the original Singer grease made in 1950, very smooth between the fingers, but I have no idea of it's melting point, petroleum or synthetic. Then again, if petroleum jelly is very good stuff?