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Mr. Wilson how to use diode

Geo-TH,In

Geo-TH,In

Well-known Member
This is how I used a diode on my Jubilee to make a hotter spark when starting. The anode end gets 12v off starter. Jubilee solenoid has no 12v terminal, solenoid is grounded by starter button on tranny.
a246816.jpg
 
A diode by allows you to bypass ballast and
apply 12v to a 6 v coil for a hotter spark
than using a 12v coil.
 

I don't get it.. The typical silicon diode has 7 tenths of a volt drop. You are applying 11.3 volts to a 6 volt coil even with the diode. Actually more than that when the alternator or generator is operating. Thinking the coil is still being stressed.

If the diode is only used for starting then it's probably OK but am getting the impression some are actually running it all the time?
 
As an added 'bonus', it even allows you to start the engine without turning on the ignition key! :twisted:
 
A diode is basically a check valve for electricity.

I really try to teach my young engineers how fluids and electricity behave similar, learn one the other is easy.
 
Thomas Edison invented the first. It was a vacuum tube. He discovered electrons would bubble of hot metal in a vacuum and would travel to the cold plate when the hot metal was connected to the negative and positive to the plate.
 
Assuming anode of diode is tied to output post of start solenoid that goes to activate the starter. If so, with the switch off, as soon as solenoid releases that voltage will disappear and engine should die, regardless of condition of a fuse or ballast resistor.

If tractor has a Delco alternator with internal regulator and no isolation (diode, lamp, resistor) in line from #1 pin of alternator to switch output the engine could continue to run with switch turned off.
 
I have no way to confirm, but I think applying 12v to a 6v coil will make a hotter spark when starting. How simple is it to add a diode?
 
I don't get it?? A diode as has been stated is an electric check valve. Why do you need one in line to give your 6 volt coil 12 Volt?? Deere used this system for years with no diode. They used a 6 volt coil with a resistor in line to get 6 volt at the coil. Then when starting a wire comes directly from the starter to the coil to give it 12 volts when starting. Your diode system makes no sense to me.
 
(quoted from post at 17:55:36 12/31/16) I don't get it?? A diode as has been stated is an electric check valve. Why do you need one in line to give your 6 volt coil 12 Volt?? Deere used this system for years with no diode. They used a 6 volt coil with a resistor in line to get 6 volt at the coil. Then when starting a wire comes directly from the starter to the coil to give it 12 volts when starting. Your diode system makes no sense to me.
Click to expand...
imply because his tractor does not have the very different solenoid (extra contact) that Deere had, which by the way is the same way GM cars & trucks did it for more than a decade.
 
(quoted from post at 14:34:06 12/31/16) I have no way to confirm, but I think applying 12v to a 6v coil will make a hotter spark when starting. How simple is it to add a diode?
Click to expand...

I've always wired my ignition systems so that the 'S' ('start') position on the switch bypasses the resistor and supplies 12v to the coil during start up. I guess I just don't get the need or desirability of using a diode for that function. 8)
 
Hello Geo-TH,In,


Sure you can!🔧 If by hotter you mean more volts, a voltage test wood tell the story,!

Guido.
 
On several tractors of various brands, the starter switch is mechanical and has no terminal for a bypass to the coil. Others have a relay to the starter that has no 4th terminal for bypassing (Ford cars/trucks had the 4th terminal). If a vehicle had a ground to engage starter relay (many old Ford tractors) again no source for 12v for starting. Wiring the bypass to the battery side of any of the above, caused the ignition to be on all the time. If wired to the starter motor side of the relay or switch the bypass will work (briefly) while starting, but the ignition system will try to operate the starter motor. (the smoke rolls) The diode is a easy answer to provide 10 or so volts (cranking voltage drop) to the coil for nice hot temporary ignition "encouragement" and preventing back feeding the starter motor which has about 0.15 ohms. Jim
 
That how cars were wired, but Jubilee has a
starter button that energizes solenoid by
providing ground. No ignition switch like
cars use. No terminal on solenoid to
By pass ballast. 'Other tractors mat use a
manual starter button, No solenoid, then
only option is diode if you convert from 6v
to 12v.
 
Back in the late 50's I put a resistor bypass starting system on Dad's Moline GB propane tractor. They originally came with a 12V coil that did not need a ballast resistor. The tractor was a poor cold weather starter and was hard on points, usually had to replace them twice per year.
We had a wrecked 55 Chevy with ballast resistor and matched coil that was a great cold weather starting car. I wondered if I could improve the tractors cold weather starting by fitting it with the Chevys resistor bypass ignition system. I fitted the Chevy coil and ballast resistor to the tractor , but the Moline did not have the 4th solenoid terminal to bypass the ballast resistor while cranking. I knew I could not connect a bypass wire directly to the starter stud as it would back feed power from the coil into the starter which would short out the ignition. I got around that by using the 55 Chevys horn relay to feed 12V to the ignition coil to bypass the ballast resistor and feed 12V to the coil for better spark when cranking. When not cranking, the relay opened the connection to the coil so I would not back feed to the starter.
The system cobbled together out of junked Chevy parts worked well. The tractor would now start in much colder weather, but also a set of points would last an entire year, so I suspect the Chevy coil and ballast resistor must have pulled less amps through the points which about doubled point life.
 
There are a lot of ways around a problem.
To me, the question is What is wrong with you tractor?
Why does it need a "hotter spark" then it was designed with?
It's already been converted to 12V and that's still not enough?
It might be time to look into the root cause.
 
Now we have switched from the original post of using a diode, to will it run with key off. I wired my jubilee so the key controls both terminals to alternator, so mine will start with key off and die when I stop pushing on starter button.

I wired my alternator that way because new alternator had a small drain on battery and I saw no benefit in not sending both alternator wires through the switch.

Now you have given a very good reason why you should run both alternator wires through the switch.
 
(quoted from post at 20:52:43 12/31/16) That how cars were wired, but Jubilee has a
starter button that energizes solenoid by
providing ground. No ignition switch like
cars use. No terminal on solenoid to
By pass ballast. 'Other tractors mat use a
manual starter button, No solenoid, then
only option is diode if you convert from 6v
to 12v.
Click to expand...

Yep-you're right........if a guy wants to stay with the manual start button then he'll have to push it with one hand and turn the ign. switch to start with the other, also gotta buy and wire in a solenoid. :x ........ a diode looks better all the time! :lol:
 
(quoted from post at 04:56:19 01/01/17) Back in the late 50's I put a resistor bypass starting system on Dad's Moline GB propane tractor. They originally came with a 12V coil that did not need a ballast resistor. The tractor was a poor cold weather starter and was hard on points, usually had to replace them twice per year.
We had a wrecked 55 Chevy with ballast resistor and matched coil that was a great cold weather starting car. I wondered if I could improve the tractors cold weather starting by fitting it with the Chevys resistor bypass ignition system. I fitted the Chevy coil and ballast resistor to the tractor , but the Moline did not have the 4th solenoid terminal to bypass the ballast resistor while cranking. I knew I could not connect a bypass wire directly to the starter stud as it would back feed power from the coil into the starter which would short out the ignition. I got around that by using the 55 Chevys horn relay to feed 12V to the ignition coil to bypass the ballast resistor and feed 12V to the coil for better spark when cranking. When not cranking, the relay opened the connection to the coil so I would not back feed to the starter.
The system cobbled together out of junked Chevy parts worked well. The tractor would now start in much colder weather, but also a set of points would last an entire year, so I suspect the Chevy coil and ballast resistor must have pulled less amps through the points which about doubled point life.
Click to expand...


Jon Hagen Any relation to Hagen's in Iowa or Missouri My grandpa was Cecil E Hagen
 
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