Cub alternator issue

[jimodekerken1985]

if you have the delco with 3 wires 1st make sure you have battery voltage at the stud on the back of the alternator, if so then jump the wire marked #2 on the alternator in the diagram and see if it charges, should be around 13.75 to 14.5 volts if working

How do you mean? jump #2?

[Eugene]

How do you mean? jump #2?

Battery voltage to #2 terminal.

There is a possibility that the alternator is faulty. It appears that the alternator is not supplying 12 volts to the #1 terminal when the engine is running.

Looking at your wiring diagram, you need either the ballast resister or a 12 volt coil with resistor - - not both.

[jimodekerken1985]

How do you mean? jump #2?

Battery voltage to #2 terminal.

There is a possibility that the alternator is faulty. It appears that the alternator is not supplying 12 volts to the #1 terminal when the engine is running.

Looking at your wiring diagram, you need either the ballast resister or a 12 volt coil with resistor - - not both.

I have a 12 volt coil with resistor, not an external one.

[jimodekerken1985]

if you have the delco with 3 wires 1st make sure you have battery voltage at the stud on the back of the alternator, if so then jump the wire marked #2 on the alternator in the diagram and see if it charges, should be around 13.75 to 14.5 volts if working

Update: i jumped #2 terminal from the battery stud and the system charges, about 14,4 volts. As soon as the ‘idiot light’ is in position the charging stops (maybe thats another reason for calling it that way). Take it out and it works once in while.
Jumping the #2 terminal causes the alternator to heat up tremendously.

So… what to do next?

[jimodekerken1985]

Maybe another option to persue…
I managed to fix the 74 year old generator… it generates about 17 volts @ 1800 rpm when i adjust the brushes to the max. Only the cut out relay is 6v based, exchanging it with a 12v regulator would be a possibility?

[Eugene]

Keep the alternator. What I/we have found out is that changing to a 12 volt alternator is usually less expensive than purchasing a quality voltage regulator.

[Glen]

Hi,
Below are pages from the 1949 Cub owner's manual telling about setting the 3rd brush in the generator.
The info is for the Delco generator with cutout, or Relay IH called it, on top of it.
The generator is meant to be used with a 6 volt system.
The info begins on the right side of the page.

https://farmallcub.com/rudi_cub/www.cle ... age-36.jpg

https://farmallcub.com/rudi_cub/www.cle ... age-37.jpg

[staninlowerAL]

Keep the alternator. What I/we have found out is that changing to a 12 volt alternator is usually less expensive than purchasing a quality voltage regulator.

Agree with Eugene. Reading your introduction post on page 1, you have already said that availability and price of 6v parts is a problem so that's a good reason to keep the 12v system conversion. In addition, even though you got the 6v generator is working, how long will it last? JMHO Stan

[jimodekerken1985]

Keep the alternator. What I/we have found out is that changing to a 12 volt alternator is usually less expensive than purchasing a quality voltage regulator.

Agree with Eugene. Reading your introduction post on page 1, you have already said that availability and price of 6v parts is a problem so that's a good reason to keep the 12v system conversion. In addition, even though you got the 6v generator is working, how long will it last? JMHO Stan

Ok, clear enough,thanks.
I’ll continue searching where things go wrong.
Suggestions are welcome though.

[jimodekerken1985]

Figured it out…
Solution was in the adding 2 diodes.
1 before the warning light and the other one on the + of the ignition coil.

I’ll draw out the diagram and share it here.

[jimodekerken1985]

This is the final diagram with the diodes in place.

[Gary Dotson]

What’s the purpose of the diode, in line to the coil? I see no purpose or need for it. Otherwise, it’s the same as I generally set them up.

[jimodekerken1985]

Well I don't know exactly, but it works.
The conversion of the original magneto ignition with an external internally resisted coil in combination with an alternator without both diodes still caused the warning light to remain on.
Somehow somewhere there was somekind of interference (AC?) 2 diodes on these locations seemed logical. And have proven to be effective.

[phill_mi]

I agree with Gary's comment. I can't see any need for the diode in series with the ignition coil. I also run the wire from pin #2 back to the battery's + terminal to take advantage of the voltage sense input monitoring the battery without any voltage drop in the wiring.