wiring question

[marc walker]

I used farmall bobs # 5 wiring diagram for this A with the 135 engine bypassed the starter relay, worked great took it across the road today and used the turning plow worked fine . when I got back home the alternator had stopped working, Delco 1102913 61amp 8E10 neg ground 3 wire, I had one in the shop Delco 1102480 61amp 8D13 3 wire neg ground. Put it on the tractor flipped the switch showed discharg hit the starter charged fine. fliped the switch to off tractor keeps running. What it wrong? Thanks as always. Marc
 

[Janicholson]

If one of the following: a 10 ohm resistor, Marker lamp, or 3 amp diode connected with the band end to the alternator, is not in series with the #1 terminal wiring to the ignition, it will not shut off. Jim
 

[marc walker]

I have been running the tractor off and on for the past week with no on/off problems, it started acting up when I changed the altenator today. Marc
 

[Janicholson]

does it have the diode or lamp, or resistor in the #1 terminal connection? If the original Alternator was a One Wire design, it might work with that terminal connected and not fail. but a real 3 wire must have it, no exceptions. Jim
 

[marc walker]

Jim, it has none of the above in line, I can disconect the jumper from the #2 side wire to large battery terminal and the on/off switch works. So I will add a diode tomorrow, will that be sufficent? .Thanks for the help.
 

[Janicholson]

The diode goes in the wire from #1 to the ignition, with the band on the diode toward the alternator #1 spade terminal. The #2 terminal should be connected to the Big output terminal going to the amp meter. (short lead) it needs to be able to handle about 3 amps. (an old alternator can be scavenged to take apart the diode bridge removing one of the 6 diodes. (these are often not marked for polarity, so test it to assure it cannot pass electricity from the alt to the ign. but will from ign. to alt. Jim
 

[old]

Radio shack part #276-1661 works great and cost around $2.50 for a pack of 4 and it over kill so you never have to worry about burning it out. The silver line goes to the alternator side in the #1 wire off the 2 wire plug
 

[marc walker]

I'll get her done tomorrow, Thanks for your time. Marc
 

[Owen Aaland]

The wire on the #2 terminal is the voltage sense wire. When that wire is disconnected the alternator stops charging. (at least that is the way Delco Remy designed it) Since it is no longer charging there is no voltage to back feed the ignition system and the engine shuts off with the switch.