(800) 853-2651
SHOP NOW

12V Square Coil

D

DrLarryE

Member
Tim PloughmaN has been helping me diagnose some (probable) electrical problems with my 9N but while at the local "tractor" store I saw something I want to ask about. There was a 12V square coil that specifically said "no resistors needed if alternator voltage is not over 13.5V". Is this a different coil than is talked about here because it is usually stated that the ballast resistor would still be needed with a 12V square coil.
 
At the risk of being labeled a heretic, I have been using a 12 volt coil on a 9N converted to 12 volts without a resistor for 5 years. No
problems to date. I think the new square coils are probably more robust that the original ones. Note, I do use the ballast resistor on my
front mount dist tractors that are still 6 volt.
 
I've always wondered why they couldn't (or didn't) make a square 12V coil that couldn't just be connected to the system without any resistors. Seems like it would solve a lot of confusion/problems.
 
Everything I have read or heard indicates PROPER 12 volt battery charging needs to be close to 14.25 volts... I would be unhappy to find my alternator only charging at 13 volts.... Your Call.....
 
I don't know the answer to your question Larry.
But if the resistor or connections to it are suspect, why not
bypass it temporarily and see if the problem is resolved?
It won't hurt anything for a short duration test.
 
(quoted from post at 11:03:35 09/29/19) At the risk of being labeled a heretic, I have been using a 12 volt coil on a 9N converted to 12 volts without a resistor for 5 years. No
problems to date. I think the new square coils are probably more robust that the original ones. Note, I do use the ballast resistor on my
front mount dist tractors that are still 6 volt.
Click to expand...
I beat you. ran my 1940 for nine years with out one, then I sold it.
 
The front mount 6V 'square' coil requires the OEM Ballast Resistor. When fellas do 12V jobs, they often discard the ballast resistor. Some run fine, some don't, some will for while; it depends on what your primary is. On a 12V front mount, it was best to add the external, in-line, white ceramic 1-OHM resistor to the circuit. If on a Front Mount 12V switchover, a 12V coil can be purchased and not the external resistor. I've seen some with the ballast resistor, some without, and every combination in between. There are but a handful of correct ways to wire the 12V system and about a 1001 incorrect ways. Often I see units run without any resistor or just the 1-OHM one, but they are simply running straight off battery voltage then have to be charged when they fail. You can do whatever you want, it's your tractor.

Tim *PloughNman* Daley(MI)
 
(quoted from post at 09:31:56 09/29/19) Tim PloughmaN has been helping me diagnose some (probable) electrical problems with my 9N but while at the local "tractor" store I saw something I want to ask about. There was a 12V square coil that specifically said "no resistors needed if alternator voltage is not over 13.5V". Is this a different coil than is talked about here because it is usually stated that the ballast resistor would still be needed with a 12V square coil.
Click to expand...

It would seem they are claiming the coil is different than the other coils that are intended use with a resistor. If you doubt that; simply check the primary resistance of the coil. A 12 volt coil for use without an external resistor should have a primary resistance of 3.0 ohms (nominal). A 6 volt coil for use without an external resistor should have a primary resistance of 1.5 ohms (nominal).

Do they tell you how to insure the alternator charging voltage will never exceed 13.5 volts? Typically alternators for US vehicles regulate at 14.5 volts. (nominial).
 
You must log in or register to reply here.

Similar threads

63mercragtop
Farmall A 1941 Magneto Conversion
2
Replies
26
Views
797
teddy52food
T
W
Ferguson TE20 - converted to 12V with a generator?
Replies
9
Views
943
Jim.ME
J
J
coil resistance
Replies
8
Views
426
jds535
J
K
50 with a 6 volt coil
Replies
12
Views
423
Pete in MD
Pete in MD
Geo-TH,In
Why mess around with a ballast resistor when you can ?
2
Replies
25
Views
1K
Geo-TH,In
Geo-TH,In
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.

Copyright © 1997-2024 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

Back
Top