S35 generator

[BrianReynolds]

Hello All,
Ok, yet again I need the benefit of your expertise. Rebuilding my 57 S4 engine, just assembled the generator ready to install to set the valve timing. Did the usual spin test on the S35, nothing, not even smoke. It was dismantled, cleaned, looks good, new bearings etc. I need the detailed test procedure to figure out what is wrong. Bear in mind I am in rural Manitoba, Canada, a long way from knowledgeable support or parts. I have a comprehensive machine shop and testing equipment. As always, advice appreciated. Thanks.

[Roger Gwynn]

If you are a member see the library, document repository/generic/lucas

[BrianReynolds]

Thank you Roger, yes I am a member so will take a look. Thank you.

[Chris Sealy]

Hello Brian. Assuming that you are spinning it fast enough; a battery powered drill may be too slow; then the most likely reason for lack of output is that the residual magnetism has faded away, due to lack of use.
As its name suggests, residual magnetism, is what's left in the iron pole pieces when the dynamo is at rest.
Its presence is essential for the dynamo to produce an output, after a period of rest.
It is quite easy to restore. Simply connect a battery between the body of the dynamo, and the Field contact for about two seconds.
Make sure that the wire connected to the body is the same polarity, as you will be using as frame earth, or ground.
There will be sparks, so watch your fingers. If you don't get sparks; the Field coils are open circuit.
The Field contact is on the right.

[BrianReynolds]

Hello Chris, thanks for the response, something I will try. Further to the previous post I felt that I was missing something so today I dismantled the generator (again!) thoroughly cleaned everything, already fitted new bearings etc. Set up the rotor in the lathe, polished the commutator and cleaned the grooves between the segments. Checked each segment for any fault to ground ( shaft) all OK, very clean. Checked the total resistance of the coils, manual states 2.6 - 2.8 ohms, I am at 2.7. No obvious damage. Assembled the generator, Checked and cleaned the brushes, good fit. Tried the spin test ( F&D linked to negative on a battery, positive to ground. There was a kick of the shaft as though it was starting to spin then it stopped. when trying to rotate by hand there is distinct magnetic resistance. No overheating, sparks etc. Set it up as a complete generator in my lathe and run at 1000 rpm, no output. I am at a loss. The engine had not run for at least 20 years when I got it, so worth trying your suggestion, but certainly open to any advice as to what this issue could be. Thanks.

[BrianReynolds]

[simon.holyfield]

Individual armature coils shorting each other? Just thinking aloud, and not an expert here, but adjacent commutator segments shouldn't connect to each other. The armature is a bundle of coils, and each coil has a segment at each end, so each segment should show continuity to one other.

[Mick D]

Hi

Going on your progress to date I'd concentrate on the electrical path from the 'F / D' connector to the commutator, it sounds like the armature side of things is fine.

Good luck Mick

[BrianReynolds]

Thanks, so far everything I have tested appears to be fine, I did remove the F/D Bakelite plate, cleaned and checked for cracks etc, all looks good, brushes as new. Connections clean, I am at a loss. I am halfway through assembling the engine and need the generator to assemble the timing gear etc.

[Mick D]

Hi

Have you done continuity checks from F/D to the commutator and is it good when the armature is moved?

Regards Mick