Hi all, recently I did install a 3G alternator, 160Amp - 12V on My F150 1986. It is working really nice but I need some clarification:

The voltage regulator Connector has 3 wires as fallows, one Wht/Blk going to alternator connector, one Lt Grn/Red going to cluster charging light, one Poer Red going to Starter Relay/Battery + and finally...

There is a Yel/Wht connected directly to alternator B+ Output terminal, I have seem some installations like Explorer's where this wire is connected to a 15 Amp fuse located in the Engine Comp. Fuse Box OR 20 Amp fuse located inside a Inline fuse holder close to alternator.

My question is: should I install this fuse also? why not all vehicle applications doesn't use this fuse? This fuse is installed to protect what? the Regulator? diodes?? anything else???

Thanks in advanced for your help??

Here are some diagrams:
http://s54.photobucket.com/albums/g9...97Charging.gif

This is my actual wiring http://s54.photobucket.com/albums/g9...96Charging.gif

 

The only reason I see for fusing the yellow/white wire is because sometimes it's connected to a large wire which goes directly to the battery + terminal. If the yellow wire was to become shorted to ground, there would be all that potiental of the battery on the yellow wire, which could cause a fire.

I was looking at some of the other diagrams, and if you notice in those that do not have the yellow wire fused, the yellow wire is always hooked downstream of a maxi fuse or a fusible link between it and the battery +.

The yellow/white is the sensing or feedback wire for the regulator. It tells the regulator the voltage level of the elec system, and the regulator varies the output of the alternator based on the yellow/white wire's info. So you can actually vary the voltage level of different parts of the vehicle depending on where you hook the yellow/white.

So, if you have a maxi fuse or fusible link in the large output wire going from the alt to the bat +, and the yellow/white is downstream from the link or fuse, you should be ok. If you don't have any protection on the large wire, but the yellow wire is very short and jumped right around to the bat + wire near the alt, I would not worry too much, since the wire is so short and should be in less danger of damage.

If you are worried about it, an inline fuse should work ok, but make it fairly large(I notice the factory uses a 15 amp). Fuses have natural voltage drops, smaller fuses having more. So that may make the system voltage run a little high and give battery water problems.

 

Ok, thanks for the info, it have sense to me, very clear.

There is a fuse link 175Amp at the alternator output and the yellow wire is very short. But since this is the voltage sense for the alternator, I'm going give more brain to the location of this wire in the electrical circuit in my truck. Wiring it directly from the Engine Comp. Fuse Box will compensate for small voltage droops on cables..