Generator woes part 3

[Sean Jackson]

So I’m back to messing with the generator again, again. 
1948 Windsor- all stock. 
 

Earlier today I was driving around and noticed a no-charging condition. First I checked the VR as it has been the biggest cause of headaches yet. The breaker contacts were simply not closing with the engine revving. At first it was slightly moving toward closed so I assumed the generator was making some juice but not enough. I pulled the generator brush strap and inspected everything, but nothing seemed to be out of the ordinary. With the engine off I manually pressed the VR breaker contacts closed to see if the generator moved (motored) at all and I could feel the slightest jump as if it wanted to turn (belt still connected). It was very weak, just the slightest jolt. The points did show a small spark upon releasing. 
I then moved on to other tests with the engine running.

Grounding the field and bringing the engine above idle yielded nothing on a voltmeter across the battery and no movement at the ammeter. Removing the armature wire at the regulator and striking it against ground yielded no spark. 
 

This must point to a generator issue, but I am at a loss at what could’ve gone wrong with it. Open winding? Are there any basic tests I can do with an ohmmeter to see what has failed?

 

Thank you
 

[Sean Jackson]

So I yanked (more like grunted) the generator out of the car and put it in the vice for the basic motoring test. 
Grounded the field terminal to the case, applied battery negative to the armature terminal and +6V to the case of the generator. 
The generator spins nice and fast in this configuration. Disconnecting the field terminal from ground it stops (as it should, right?). I have good continuity everywhere- from A terminal on generator to A terminal on VR, and from F terminal on generator to F terminal on VR. Generator case is grounded to engine block solidly.
How come the thing just won’t charge? When I run the car and hit the armature terminal to ground I get no spark, that test should bypass the VR entirely right??
I’m pulling my hair out over this one

[Sean Jackson]

Alright, generator is back in the car and it is functioning as it should. The VR must’ve decided to go out. I can’t figure out why it failed the first test, but as of now the gen. is putting out what it should when spun by the motor and can generate more than enough juice. I ran the engine, put a voltmeter at the output and grounded the field. It pegged the meter when I briefly revved the engine so I know it’s working. I guess these aftermarket VRs have about a one year lifespan. What junk. 
 

anyway, I’ll just order an NOS AutoLite and take it to the shop to have it all adjusted properly. 
thanks for reading

[Sam Buchanan]

The aftermarket VR I bought was DOA....but I fixed it:  

 

Edited September 15, 2022 by Sam Buchanan

[Dodgeb4ya]

4 hours ago, Sean Jackson said:

Alright, generator is back in the car and it is functioning as it should. The VR must’ve decided to go out. I can’t figure out why it failed the first test, but as of now the gen. is putting out what it should when spun by the motor and can generate more than enough juice. I ran the engine, put a voltmeter at the output and grounded the field. It pegged the meter when I briefly revved the engine so I know it’s working. I guess these aftermarket VRs have about a one year lifespan. What junk. 
 

anyway, I’ll just order an NOS AutoLite and take it to the shop to have it all adjusted properly. 
thanks for reading

Modern chinese VR's are absolute junk...don't waste your time with them.

Find a good NOS Autolite or equivalent...sad to say this is the only long lasting way.

[Kilgore47]

16 hours ago, Sam Buchanan said:

The aftermarket VR I bought was DOA....but I fixed it:

My what big cables you have.  I have the same set up.  Removed the generator and went with a six volt positive ground alternator and that fixed all the charging problems.

[Sam Buchanan]

36 minutes ago, Kilgore47 said:

My what big cables you have. 

 

The better to eat the electrons!   ?