I have a generator that I am unable to adjust below 19 Amps charge using methods according to MTFCA electrical system book previously successful on other generators. This generator I have...
-Fitted new glass fibre insulators
-Fitted new brushes
-Re insulated field tails
-Replaced terminal insulator
-Set null point according to book
-Using a quality external analogue Amp meter
...but still with 3rd brush fully away from block the minimum current output on the external analogue meter is 19 Amps which just increases moving 3rd brush towards block. I have a Fun Projects VR that I want to use but certainly not at 19A! I need to get the current way down, any ideas please. Many thanks John
I think your problem is the death point setting. I was there some time ago and redone the death point setting. After this I could set the charging from 0Amps to over 10Amps without any problem than my Ampere was toasted. After I use a 7.5amps fuse in serial with the amp-meter. The fuse is cheaper as a new amp-meter.
I also test the generator first without a cutout or a VR. Only as the test results are right I go for the cutout or the Fun Projects VR, depends on what the friends are going for.
Andre has some good suggestions. Might be helpful to get another set of eyes on the problem to check it out as well. Sometimes we all develop those "mental blocks" and miss obvious things repeatedly. Besides going back over your work and basic settings, I would do a continuity check on your entire wiring system. Sometimes and "open" in the wiring system will cause weird things to happen. One time I was driving and noticed my generator output spiking intermittently. Turned out to be a bad battery ground to the chassis. Cleaned things up and never had another issue.
Andre / Kevin, thank you for your response. Yes I did double check with a friend and got the same issue. With the null point set perfect (no rotation either way). However we have found by setting the null "very" slightly off so it just rotates then we are able to get a good range (low to high current) of adjustment by the 3rd brush. Not sure why but solved the problem, thanks again.
John, Glad you solved your generator issues. It might not be a manual approved solution, but never argue with what works.
Fine to read you found a solution for your generator problem. Sometimes you need to try things that are not written.
Interesting solution. I would love John Regon to comment on this.
I had the same problem and after searching
I found the brushplate lead setting procedure in an old post:
You will need a helper to watch the ammeter while doing this.
Loosen he third brush and move it to the fully retarded (counterclockwise as viewed from the front of the car) position. Tighten the third brush nut. Start the engine, run at a moderate speed and loosen the four 6 X 32 screws in the brushplate cap about one full turn. With your fingers move the brushplate inside the cap back and forth till the ammeter reads about 2 amps charge. Tighten the four screws. Now set the third brush to the desired charging rate.
If the generator is working correctly that should correct the problem.
Third brush regulation and the twisting magnetic fields requires the brushplate to have a small amount of "lead" with respect to armature. The problem is what is a small amount. The window is quite large and if it is off the charging current cannot be adequately controlled by the third brush setting.
With today's type of driving (assuming not all night time with he lights on) the generator will keep the battery charged at 5 Amps output.
Ron the Coilman
Ron is right of course......
I had the same problem once and having experience with repulsion induction motors figured that's what needed to be done but Ron asked me to call him to verify what needed to be done.
In fact he even called me back to ask if that resolved the issue.
What a guy........
Thanks Clifford and Craig, that gives me confidence in my own findings regarding the null adjustment. Thanks again. John
The repair manual says, set the null adjustment to the point the generator wants to motor but does not.