Farmall Super A charging help - 6v pos ground.

[tractorsam]

A little backstory - my 53 Farmall Super A has been sadly
neglected and under used for the last 5 years or so and has
developed a charging problem. After getting it going last year I
replaced the dud battery and it still wont charge. Its all
original and I messed around with the regulator to no avail, life
happened, winter came, and now Im trying to get to the
bottom of it.

I was thinking my issues lay within the regulator (as old as the
hills) but Ive verified my ammeter (both ways), and if I ground
the field coils I can hear the engine load up but the ammeter
reads a significant discharge (and my multimeter confirms the
battery voltage dropping). I have attempted the motor test on
the generator and if I power the armature it motors nicely.
With the field grounded, it will not motor. If its motoring and I
ground the field it rapidly slows and even appears to try and
reverse. Im thinking the field coils of my generator have
failed. Does this seem correct? Thanks, Sam

 

[Janicholson]

It may be that the field is internally shorted (not to ground, to itself). this can cause high current flow through the field. The fact that it stops quickly when the field is grounded is an indicator. Field current should be about 3 to 4 amps. Jim

 

[tractorsam]

So if I was to apply power to the field post on the genny and measure the current I should get 3-4 amps? Ill give it a whirl sometime soon.

 

[BarnyardEngineering]

Look up "John T's generator troubleshooting procedure" on this site. Heck he might even be along to post it.

I printed it out and stuck it in my service manual so I'd have it out in the barn.

 

[tractorsam]

Appreciate you mentioning it. Thats what I followed to get me
this far.

 

[Janicholson]

NO not that. The field is not grounded internally. it is grounded in the regulator and gets its hot side from the Armature post, or a third brush in the generator. Putting negative source voltage there would not show anything. (both sides getting negative is no flow) put the amp meter in the field circuit and a ground like when motor testing, but check the amps while applying a jumper from Neg to the Armature terminal. (regulator should be disconnected for this). Jim

 

[tractorsam]

Got it, thank you!

 

[gene bender]

ground the field if that makes it charge the reg is bad if grounding the field does NOT make it charge the gen is bad. ALL COMPONETS NEED TO BE GROUNDED FROM THE REG TO THE GEN TO THE LITE SW