Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Ford 9N, 2N & 8N Discussion Forum
:

12 v conversion

Welcome Guest, Log in or Register
Author 
Jon-Ia

11-28-2004 08:32:22




Report to Moderator

What is the purpose of the marker light? Can a diode be used instead? Whats the best place to run the P2 lead one the three wire installation? Thanks




[Log in to Reply]   [No Email]
Bob

11-28-2004 09:03:02




Report to Moderator
 Re: 12 v conversion in reply to Jon-Ia, 11-28-2004 08:32:22  
The purpose of the marker light is to emulate the "idiot light" the alternator was originally designed for.

The "194" bulb passes enough current to excite the alternator, but limits the current to a level that will not be enough to backfeed the ignition system, and cause the engine to keep running with the ignition switch shut off.

A diode, connected with the cathode end to the #1 alternator terminal will work. I use 2 - ECG-125 diodes in parallel. This is WAY OVERKILL, by the specs, but having done a lot of these conversions, I had occasional failures with smaller diodes. The ECG-125's are 2.5 amp, 1000PIV.

The #2 lead is for voltage sensing, and on the simple "N" electrical system, jumpering it over to the alternator output stud works just fine. Here's a treatise on the "sense" wire:

[Log in to Reply]  [No Email]
Dell (WA)

11-28-2004 09:00:33




Report to Moderator
 Re: 12 v conversion in reply to Jon-Ia, 11-28-2004 08:32:22  
Jon..... ....the purpose of the marker-lite is to act like the "idiot-lite" that the 3-wire Delco alternator uses in GM automobiles. It decouples (technical term) the built-in electronics guttz from the tractors ignition ON switch. Iff'n you don't stop the backfeed of volts from inside the alternator out P-1 (switched excitation) you will NOT beable to stop your engine when you turn your ignition switch off.

Yes, the diode will decouple the P-1 volts and allow you to stop your engine. It is one of 8-ways that I know to stop the backfeed of volts to the ignition coil.

P-2 (remote volts sense) should be shortwired to the BIG BATT STUD on the back of the alternator..... ....Dell, a 12 volt advocate for the right reasons

[Log in to Reply]  [No Email]
Jon-Ia

11-28-2004 09:28:27




Report to Moderator
 Re: 12 v conversion in reply to Dell (WA), 11-28-2004 09:00:33  
Ok, I must be confused. The P1 lead marked "F" on the case of the alternator goes directly to the large "batt" terminal of the alternator already. The P2 lead marked "R" on the case of the alternator is the one that's confusing me, it runs alongside the large "batt" lead up to the area of the switch and appears to require exciting to make the ammeter work.



[Log in to Reply]  [No Email]
Bob

11-28-2004 09:56:05




Report to Moderator
 Re: 12 v conversion in reply to Jon-Ia, 11-28-2004 09:28:27  
Ignore the "R" and "F" markings. When the 10SI alternators first came out, a certain number were made with a "dummy" voltage regulator inside that were used with the old-style external mechanical regulator. The "R" and "F" markings are a carryover from that, as they correspond to the connections on the older alternator series the 10SI replaced. (As one example of a setup like I just described, I have a 1972 Olds "88" that is set up that way.) With the the internally regulated alternators, the "1" and "2" markings are what we're concerned with.

Going by the #1 and #2 markings, #1 is "switched excite" and #2 is voltage sense. If you reverse the two wires, the alternator will work, but will drain the battery while the engine is shut off.

If you look around the "MAD" website, from the link I posted previously, there are PAGES of detail on this.

[Log in to Reply]  [No Email]
Dell (WA)

11-28-2004 09:55:38




Report to Moderator
 Re: 12 v conversion in reply to Jon-Ia, 11-28-2004 09:28:27  
Jon..... .....looking at the BACK of your alternator, P-1 is the blade closest to your BATT STUD. Shortwire P-2 (Remote sense) to the BATT STUD. Connect P-1 (switched Field excite) thru diode or idiot-lite to ignition switch ON..... ...Dell



[Log in to Reply]  [No Email]
Gary Prestridge

11-28-2004 08:47:14




Report to Moderator
 Re: 12 v conversion in reply to Jon-Ia, 11-28-2004 08:32:22  
Link



[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy