Burnt stator yellow wire three-spade-plug revisited

[Bixxer Bob]

I was searching for help on a non-Girly problem (blown solar panel regulator in my motorhome) when I found this neat little explanation that more or less agrees with the supposition that dirty spade connectors in the three-wire-plug are the root cause of many charging faults.  The dirty connections overheat and draw a lot of current thus killing the reg rec or the stator or both.  It's only short and worth a read.

http://support.morningstarcorp.com/search/?search_product=99

Edit: bugger, wrong link, stand by....

OK, couldn't copy the link, so copied the text:

When two conductors (a wire and screw terminal for instance) are mated, there is a resistance at that connection. Usually this contact resistance is very low and poses no threat. However, when connections become loose, oxidation builds on the surfaces, or corrosion accumulates, the resistance at the connection can increase to a dangerous level.

When current passes through resistance, power is dissipated in the form of heat. If the value of the resistance goes up, so does the power dissipated (for the same amount of current). When a connection has high resistance, the heat generated at the connection can melt surrounding material such as plastics and actually catch fire.

Resistive connections can occur on any electronic device that carries significant amounts of power. It is important to periodically check the tightness of the connections and inspect for corrosion as suggested in the Maintenance section of the Operator's Manual. Along with periodically checking the connections, dielectric grease can be applied to the terminals to avoid corrosion build-up on the conductor surfaces. Mobile installations tend to be the most susceptible to developing resisitve connections because motion works cables loose from their terminals, however, resistive connections can occur on stationary installations as well.

[Sin_Tiger]

Sanding by 

[Bixxer Bob]

Sorted it and linked to the wisdom page. 

[mat-tiger1]

  I train our service engineers to watch out for that Bixxer especially on electronic circuits, we call it connector asperity.

They're microscopic peaks & valleys created where the contact plating starts to wear over a period of time & creates a higher than normal contact resistance.  (Causes havoc with electronic control systems) The areas that do make contact carry higher current than normal and tend to locally overheat!

Moral of the story, if connectors are used they should be inspected regularly (especially in dusty or humid environments) for signs of asperity which appears initially as a fine white powder on the surface of the contact which can turn grey/green as corrosion starts to set in.