Delco D-283 issues 1925 Buick Standard

[Buick Downunder]

Hi All

 

Having not worked on the Delco SG for my 1925 Standard for some time, I am finding some tricky issues have arisen, which are stopping me from advancing with the car any further.  At the worst case scenario I am getting a dead short between the field and the main body, which is starting to drive me crazy!  On a simple circuit test the positive battery terminal and the field are beeping as a short on the multimeter, as well as the two wires for the field (F & other end where the third brush connects) to ground, while A is not grounding and remains open circuit. 

 

I have pulled the unit down and everything is in very good order, apart from some wear to brushes, which are still 50% or greater in size.

 

I initially thought that I might be getting an intermittent ground through the brush holder insulators, but this is not the case.  There are no shorts until the earth brushes to the commutator are screwed in - which is as you would expect I guess.

 

This morning I attempted a careful bench test and with a dowel placed in the starter hole to pivot the brush off the commutator there is no short when you connect ground to the body and a positive lead to the battery + / ammeter pole.  Once you release the dowel and engage the starter brush to the commutator (without connecting the F terminal) it fires up the starter.  I was not sure, but I thought it would normally require you to also connect power to the F at the same time as the Batt + pole - so not sure if this is correct or not.

 

With the starter brush disengaged and positive connected to the Batt + pole - it is open circuit when you flash the A terminal, but the generator will (on occasion) spin up when you power up the opposite end of the field from F - where the 3rd brush connects.  

 

I have changed the field with another I have and it does exactly the same thing. 

 

 

Help!

 

Edited April 16, 2022 by Buick Downunder (see edit history)

[Hubert_25-25]

There is a write up on your starter generator August 4th.