Si 10 Alternator on a Ford 850 not charging

   / Si 10 Alternator on a Ford 850 not charging #1  

biker4jc

Bronze Member
Joined
Aug 22, 2012
Messages
93
Location
Burton Mi
Tractor
AC WD 45, JD 212, Ford 850
Hi all, Hope this is the right place for some help. I'm changing the electrical system on my Ford 850 from 6 volt to 12 volt using an Si 10 alternator. I've wired it with new wiring and plugs and followed the diagrams I've found online, and it still doesn't seem to be charging. I did take the newly rebuilt alternator to Advanced Auto and had them test it on their machine, and was told it was working correctly. I've done this change over before on my Allis WD 45 and it's working like a charm ......... I'm not sure where to go from here and could use some help. One of the questions I have is that I'm wondering if those alternators are direction sensitive, do they have to turn a specific direction? If not what have I missed?
 
   / Si 10 Alternator on a Ford 850 not charging #2  
Clockwise as you are looking at the pulley is the general direction of rotation. Which model 10 SI did you get? Is your tractor negative or positive ground? They make several configurations of 10SI alternators. Different voltages, different amperage, for positive and negative ground. Generally, connect the alternator charge lead directly to the positive post on the battery. Starting the motor should show an increase in voltage from the standing voltage without it running.
 
   / Si 10 Alternator on a Ford 850 not charging #3  
Clockwise as you are looking at the pulley is the general direction of rotation. Which model 10 SI did you get? Is your tractor negative or positive ground? They make several configurations of 10SI alternators. Different voltages, different amperage, for positive and negative ground. Generally, connect the alternator charge lead directly to the positive post on the battery. Starting the motor should show an increase in voltage from the standing voltage without it running.

So where did you find one set up for positive ground?
 
   / Si 10 Alternator on a Ford 850 not charging #4  
pull the small connector then... try running it up over 2400 RPM ... it should self excite at that speed ...

if it does, you have the wiring to the internal regulator incorrect ....

if it doesn't ,reconnect the small connector , bypass the internal reg by inserting a small metal pin / nail in the small D shaped hole in the back of the alt ... (look for a small metal tab to touch ) ... ground it to the alt case ... that should make the alt produce full power...

if it fails that test , the brushes / windings are faulty ....
 
   / Si 10 Alternator on a Ford 850 not charging #6  
I'm using an alternator turning the opposite direction (counterclockwise) and it's working fine. The fan still blows a lot of air even though it's going the wrong way. Just thought I'd mention it.
 
   / Si 10 Alternator on a Ford 850 not charging #7  
alternators don't care which direction they turn in ... but the cooling is reduced ( unless you get a reversed fan blade to match ) ....

the trio diode and bridge rectifier is what determines the polarity in these alternators ...
 
   / Si 10 Alternator on a Ford 850 not charging #8  
So where did you find one set up for positive ground?

If he's changing from 6 to 12 volts why would that matter? Typical conversions such as this are going to be just like our daily drivers....negative ground.

Biker, do are you positive (lol) that you have that thing hooked up properly?
You have a light or a diode in place?
Did you try juicing up the throttle to see it it will start charging?
If you don't have the excite hooked up properly? It will not charge until you throttle up, or instead of having to throttle up you can wire in a marker style light that will do the excite for you.
 
   / Si 10 Alternator on a Ford 850 not charging #9  
you noted the install of new wiring this means you took out the old regulator and all related to also there is several alternator starter shops close to you call one and get them to install transpo part number d10AC this set up allows the alternator to truly use one <1> wire to operate also it will let the alternator start charging at about 500 rpm's if they dont know about this part repost i have them in stock this is the best fix out there truly using a hot wire only to operate
 
   / Si 10 Alternator on a Ford 850 not charging #10  
Biker go check out yesterdaystractors.com and search for the ford forum, there's tons of information, wiring diagrams too.

From what I've seen and read the 1 wire jobs aren't as reliable as a 3 wire with a light. The bonus feature of having the light, when she starts charging the light goes out. If im not mistaken a 1 wire can back feed from the battery and drain it given enough time. The light or diode stops that from happening.
 
 
Top