Larry Kastens
Member
Does the 6 volt coil for a 1956 John Deere Utility tractor have an internal or external ballast? Thanks to anyone who responds.
Larry
Larry
- Thread starter Larry Kastens
- Start date
Except in very unusual cases (older "N" Fords, for example) 6 Volt tractor coils do NOT have a resistor INTERNALLY or need an EXTERNAL resistor.
You simply need a standard "round-can" 6 Volt coil, which will likely have a primary resistance of around 1.75 Ohms.
(That is the actual resistance of the primary winding itself.)
You simply need a standard "round-can" 6 Volt coil, which will likely have a primary resistance of around 1.75 Ohms.
(That is the actual resistance of the primary winding itself.)
Just a side note. When I was in my teens I was plowing with the 300U. It was still 6 volt and stock igniti9n wires. When plowing you are really using the horses. Coming up the field the tractor started running a little flukey and then POWW!!! Smelled hot tar. Get off and looked , the coil is now pretty much and empty can with a whole bunch of wire and hot tar all over the place. That is the only 6volt coil I have ever seen blow up.
Janicholson
Well-known Member
In the early battery ignition systems there were a few manufacturers that actually had a resistor inside the coil and 3 small terminals to allow that resistor to be bypassed for starting. None made today have internal resistors, the words "external resistor required" found on the coil seems to imply that there is a internal resistor in some coils. Not true. coils today are made to operate at about 7 volts (charging voltage), or 14.5 volts (charging voltage for 12v batteries) A 6v coil can use a external resistor to allow it to operate at 12v. This often includes a bypass wire form a special terminal on the starter relay/solenoid, to operate at cranking voltage to assist starting. Jim
James Howell
Well-known Member
Agree.
On a John Deere 6 volt tractor their "6 Volt Coil" had NEITHER an Internal nor used any External ballast resistor.
Typical old farm tractors used EITHER 6 or 12 nominal volt rated coils NEITHER of which contained an internal discrete ballast "resistor" tucked away inside the can...??. A few older car coils indeed contained internal discrete ballast resistors that were inside the can but I (used tractor dealer in years past) never saw such on any old farm tractors
HOWEVER some 12 volt tractors used a 6 volt coil PLUS an EXTERNAL voltage dropping (6 down to 12) ballast resistor and could be equipped with a ballast by pass when cranking to improve cold weather starting.
Got it ???
John T
Typical old farm tractors used EITHER 6 or 12 nominal volt rated coils NEITHER of which contained an internal discrete ballast "resistor" tucked away inside the can...??. A few older car coils indeed contained internal discrete ballast resistors that were inside the can but I (used tractor dealer in years past) never saw such on any old farm tractors
HOWEVER some 12 volt tractors used a 6 volt coil PLUS an EXTERNAL voltage dropping (6 down to 12) ballast resistor and could be equipped with a ballast by pass when cranking to improve cold weather starting.
Got it ???
John T
Larry Kastens
Member
Thanks to all of you who replied and especially to James Howell for posting the schematic of the wiring. I appreciate the caretaker of this site and all of those who answer questions that I have.
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