Wiring in an alternator

~Even then you probably won't find an actual wire diagram for the installation. I have drawn a few wire diagrams for Delco alternator installations on the Dubuque tractors like the M, 40, & 420 but haven't had a need to do so on the numbered series [yet].

~In any case, IF you installed a Delco alternator [that's the most common alternator used for a tractor conversion] it is an easy conversion.

~Until we know exactly what alternator you used I will post a standard [the one I usually E-Mail] 12 volt Deere 2-cylinder tractor [Delco 10-SI] alternator installation [3 wire]. If you installed a ONE WIRE Delco disregard the parts referring to the # 1 & # 2 terminal wiring. Also IF you did install a one wire Delco alternator you might have to jump start the alternator the first time used [if that�s the case post back or E-Mail for a one wire Delco alternator initial start-up jumping procedure..

~Note: the Delco 10-SI was the standard alternator used on the mid 70's to mid 80's GM cars & trucks..

The alternator installation instructions I am posting below is just for your information & not to be used to wire to [UNTIL WE KNOW WHAT ALTERNATOR YOU INSTALLED]. It will give you an idea of what�s required to install a Delco [3 wire] alternator on a 2-cylinder Deere tractor.

~~~~~~DELCO 10-SI ALTERNATOR INSTALLATION~~~~~

How to correctly install a GM [internally regulated] Delco 10-SI alternator on a 12 volt 2-Cylinder John Deere....

~The Delco alternator you need will have the regulator terminals running like this [- -]..... ...If the regulator terminals are running like this [.l l.], it is the old externally regulated Delcotron and won't work without an external regulator. The best Delco 10-SI alternators for tractor conversions are the lower output units with a 55 or lower amp output. Due to the high parasitic loads of the higher output Delco alternators at full charge they put a fairly high load on the early tractor's fan shaft drive gears.

(1)-First, the tractor must be, or have been, converted to negative ground- [unless a high dollar positive ground, alternator is used]..... If a 12 volt ignition coil is used it should be the internal resisted type. If in doubt about the coil type, or whether it has the correct resistance for a 12 volt system, just measure the coil primary resistance between the [+] & [ - ] terminals. If the resistance is over 3 ohms it is probably an internally resisted 12 volt coil & will function correctly at 12 volts without an added ballast resistor. If the resistance is under 2 ohms it will then require a ballast resistor between the ignition coil and ignition switch, or points burning will probably occur.

(2)- The wires should be swapped at the ammeter to reflect the new ground polarity [if the ammeter reads backwards when the conversion is done, the wires that are hooked to the ammeter are connected incorrectly and will need to be reversed]. Only one wire should be hooked to the battery side of the ammeter, that should be the wire running to the battery [non grounded side], or to the starter [battery cable stud]. All other electrical loads, including the wire from the alternator rear [BATTERY] stud should be hooked to the [NON] battery post of the ammeter. The exception would be a cigarette lighter, it would hook to the battery side of the ammeter.

(3)-The old generator & regulator should be removed, and [ if so equipped] remove the ignition switch and light switch power feed wire [L] wire that ran to the old regulator�s [L] terminal. The ignition switch and light switch feed wire(s) should then be hooked directly to the [NON] battery side of the ammeter, the old [L] wire going forward to the old regulator can then be eliminated...

(4)-The alternator should be mounted so the belt is tight and not out of line. If need be, the alternator 4 case securing bolts can be removed and case halves separated slightly [not more than a 1/4" or the internal brushes will fall out], then the rear case [with stator] turned so the regulator terminals are facing out and away from engine interference or exhaust heat.

(5)-A short 14 ga. wire should be made up and run from the big [BATTERY] stud on the back of the alternator to the #2 internal regulator terminal of the alternator. That is a low power battery sensing circuit so it doesn't have to be heavy gauge.

(6)-If the alternator is over 60 amps, a 10 gauge wire should be run from the [BATTERY] stud on the back of the alternator to the [NON] battery side of the ammeter. The old wire that ran from the ammeter to the battery [or from the ammeter to the big starter cable stud on the starter] should be replaced with a 10 gauge wire capable of handling the 60+ amps from the alternator. If the alternator is under 60 amps then the wires used can be 12 gauge.

(7)-If the tractor is distributor equipped, or has an ignition switch that supplies power to the coil/mag terminal instead of ground, a 14 or 16 gauge wire should be run from the coil power terminal on the ignition switch to the #1 terminal of the internal regulator. An inline 10 ohm [2 watt + ] resistor should be installed [in series] in that wire, [that resistor isn't required for the alternator to actually operate, but is put there to protect the diode trio inside the alternator from damage due to a power surge]. Make sure the resistor isn't taped inside the harness or placed close to anything that will burn as it gets quite hot when the ignition switch is on and the alternator isn't charging [I usually install the resistor at the ignition switch]. While a little over kill, the Radio Shack 10 ohm 10 watt p/n- 271-132 works very good and is under 2 dollars.

(8)- If the system charges, and the engine shuts off promptly when the ignition switch is turned off at high RPM, that's all you need to do. If the engine won't shut down consistently, or wants to run on a little after shutdown, or you just want to make sure it will always shut down correctly, then you can install a 1-2 amp 50 volt diode [in series] in the wire that is run from the ignition switch [coil terminal] to the alternator [#1] terminal. The diode is installed in series and in addition to the added 10 ohm resistor. The diode must be installed with the polarity indicating [stripe, dot, k, +, or cath.,,,,, "cathode side"] towards the alternator and the [non] marked [anode] side towards the ignition switch. That diode is placed in the system to keep the alternator form back feeding the ignition coil when the ignition switch is shut off. Not all systems need that back feed protection [depends on the ignition coil & if the tractor has a coil shorting post on the ign switch] and once the alternator stops charging after shut down there is no additional power flow [from] the alternator�s #1 terminal to the coil terminal on the ignition switch. I always include that diode in any conversion as it is easy and cheap and it won't have to be added later if a shut down problem arises. While again, a little over kill, the Radio Shack p/n 276-1141, 3 amp power rectifying diode will work good and is well under 2 dollars.

(9)- If the tractor has a magneto, or there isn't a functioning ignition switch, a 2 terminal oil pressure switch can be added to the engine oil pressure tap and a 14 or 16 gauge wire run from the big battery stud on the back of the alternator to one terminal of the oil pressure switch, then a 14 or 16 ga. wire run from the other oil pressure switch terminal to the #1 terminal of the internal regulator. Again, a 10 ohm 2 watt resistor should be added [in series] in that wire. A diode isn't required in this circuit due to no ignition coil interface.

~Any questions? just post back or E-Mail..

[email protected]

What type of an alternator did you convert with, a one wire unit or like a GM 10 SI internally regulated (3 wire) or another???

Not knowing what you have, I will still go ahead and post a few things and maybe after you provide more information I can post back or e mail you in a day or two.

1) Do you have an ammeter?? does it work?? and does it stay at 0 when the tractor is off ??and show any charge when running or what??? If you turn on the lights tractor not running, does it swing to discharge???

2) Most alternators (including the GM 10 SI) are for use with negative ground only. Are you at pos or neg ground?? If you switched from pos to neg ground when you converted to an alternator, the ammeter leads would have to be reversed to make it read correctly.

3) If you have a working ammeter, the alternators big main output terminal should have been wired to its load (non battery) side. The ammeter should only have one wire on its supply side, and thats the wire to the starter post or battery. The ammeters other (load) side is where any lights or switches or ignition PLUS a wire down to the alternators main big output terminal is. That could be the wire down to the BAT terminal on the old Voltage Regulator if the old wire was used. On new installations, however, I replace that with a 10 gauge wire.

4) If you used a GM 10 SI alternator, theres more wires to be connected, so if thats what you have and tell me, I will then post back or e mail you telling you how to wire it up.

5) The old generator wiring could have been partly used with the old wire that was on the VR's BAT terminal now wired to the alternators main output terminal, as it leads to the ammeters load side. (but I prefer a new 10 gauge wire as posted above) The other wires and the old VR would, of course, all be gone now.

6) See if the wire on the alternators main output post has battery voltage on it now at all times????? Cuz it has to be that way for the alternators outut to get to and charge the battery via the ammeter. If the alternator is like a GM 10 SI internally regulated, the lil side 1(F) and 2(R) terminals need to be wired also, however. The 2(F) lil terminal needs to be jump wire connected up to the big main output post and the 1(R) has to be wired for excitation current.

7) Are the bateries good?? Bad batteries can discharge plus not take a charge even with a good alternator, thats why I need to know what the ammeter is doing now in my questions above.

Let me know what alternator you have, your ground, and what the ammeter is doing, and I will post back or e mail you how to wire it. Still basically, all needed is the right ground system, a wire from the alternator's output to the ammeters load terminal, plus the 1(R) terminal excited and 2(F) wired to the output if its a GM. The alternators (GM) 1(R) wirign is usually just a 14 gauge insulated wire ran from the ignition switch output (hot ONLY when ignition on) with a series 10 ohm resistor and a 5 amp diode (- side to alternator) then to the 1(R) lil terminal on the alternator.

Let me know, post back or e mail me at [email protected] or call me at 812-824-4608 and I will try and get you going.

Good Luck n God Bless

John T