Skyplane

I got an aftermarket alternator to help keep up with my subs and stuff, but now it seems to just cut out when I go over 2000RPM and it doesn't always come back on right away when it goes back under 2K, I've checked all connections, and I don't think the belt slips.

[IMG]local://upfiles/30765/F1BCD844D5D84A84A2C8DD8D35FCD519.jpg[/IMG]

Archion

Having had this problem before, it is rings that the brushes ride on, i believe they are called commutator rings, some ppl call them stator rings. They are machined improperly, I have actually seen it more and more on the offshore built units, they are probably buying China's finest. What is happening is the brushes are actually bouncing off of the rings as rpms increase, there is a way to fix it, but it involves partial disassembly of the unit (removing the regulator/brush assy.) some fine grit sandpaper or emory cloth, a lot of patience and turning the shaft and sanding the rings flat. The rings are "out of round" kind of like a warped rotor. If you pull the regulator/brush assy. you will see the uneven wear patterns on the rings, kind of like squiggly lines. You could call the supplier and tell them you have a defect, but they will want to bench test it and you will have to explain to them that bench testers do not turn that fast. This info should give you some ammo with them, good luck.

Skyplane

thanks I'll try takin that out and sanding it

Archion

Cool, just remember a Fine grit, a lot of patience, and a light hand, you are basically hand machining soft copper.

Skyplane

well I tryed doin what you said, didn't help at all. seems to be doin exactly the same as before. I prolly didn't do it right but yea, I just ordered a new alternator.