Alternator up-keep

[Scott T-Bird]

I've removed my alternator to do some housekeeping on the entire engine. When it's reinstalled, it will have a new serpentine belt kit. Looking at the back end of it, there is an odd jumper wire from the pos post to the neg post. I'm curious if this is some kind of fuse for safety or what?

This is before disconnecting the cables and wires. Below is with everything removed except the jumper.

Also, what kind of servicing can I /should I consider?

 

[justsomeguy]

https://www.prestolite.com/literature/tech/alts/TSB-1057_Universal_alternator_wiring.pdf

This help?

 

[dlochner]

It is a variation of one of these Zap Stops

Balmar TSP-12 Spike Ground Protector 12V - e Marine Systems

Balmar TSP-12 build in an additional level of system safety by ensuring an exit corridor to ground should an AC or DC spike invade the vessel’s charging system.

www.emarineinc.com

It is a diode that blocks surges in the alternator output. If a load is suddenly cut off while the alternator is running, it dumps the load to ground before the internal diodes blow. This could happen if the alternator output is wired to the common post on a 1-2-Both and the switch is turned to off while the engine is running.

As for alternator maintenance, you could take it to an auto electrical repair shop. They will bench test it and clean it up and replace anything that needs replacing. Much cheaper than a new alternator.

 

[Ken13559]

Yes dlochner is right it being a Zap Stop/Arrestor.
I made one up using couple of 24V 1N5359 zener diodes wired back-to-back.
Works just like the Sterling Power Alternator Protective Device but in simpler form.
You'll find this setup on YouTube.

Ken Y

 

[All U Get]

I've removed my alternator to do some housekeeping on the entire engine. When it's reinstalled, it will have a new serpentine belt kit. Looking at the back end of it, there is an odd jumper wire from the pos post to the neg post. I'm curious if this is some kind of fuse for safety or what?
View attachment 188942
This is before disconnecting the cables and wires. Below is with everything removed except the jumper.
View attachment 188943
Also, what kind of servicing can I /should I consider?

I’m jealous of you getting the serpentine belt, that was Maine Sails recommendation after he corrected all the charging issues we were having. One item was that little wire. Our boat has a complicated wiring system with too many redundant parts so I won’t let anyone near what Maine Sail fixed.

 

[Scott T-Bird]

Thanks for the information! It make sense to provide that protection. As far as I can tell, there is not any alternator isolation on-off switch, so I think that will also be an addition. I disconnected the cabling obviously with the selector switch off, but I am still nervous about leaving the cables loose right now. I'll have to secure them before using the selector switch.