Generator question

I

ian Simpson

Well-known member
I thought I knew all about generators until this driving season.

When we adopted our 1928 Tudor eight years ago, the generator was not working. I purchased a rebuilt generator from Snyders and a voltage regulator to replace the cut-out from George Moir. All was well until this driving season.

This spring as per usual after the six month shut down, I charged the battery and she started right up with no problem.

However, since then I have encountered a recurring problem - the generator does not charge the battery after a one day or so shut down.

Removing the battery/ammeter wire from the output of the regulator and touching it briefly to the generator output terminal gets it going again.

Performing this once or twice a year is not problematical, but going through this rigmarole every time I start the old girl up is getting to be annoying.

Still six volts, positive ground. Any suggestions?????
 
It sounds like your cut-out is sticking closed and draining the battery. Try removing the battery connection after you shut down to see if the battery continues to drain...

Frank
 
I would suspect the VR that you have. Do you have a good cutout that you could install in place of the VR for a test?
 
Is your cut-out of the original style with coil and points, or is it a more modern style with a diode ? Tap it against your hand, and if it vibrates, it is of the point style where the points might be sticking as "emf" suggests.
 
Per responses #3 & #5 he replaced the cut out with a voltage regulator.
Re- Read the original post..
I believe you can short out the regulator by jumping the wires the way you are doing it.. The regulator should be removed from the circuit before polarizing etc

You can remove the regulator from the circuit / connect the harness directly to the output stud and retest..disconnect the wire after shutting down or you'll drain the batt. Make sure your 3rd brush is set properly.. I believe your VR is the issue

I know you know most of what I mentioned, just putting it out there for others
 
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Mitch, I do cut the regulator out of the circuit by removing the wire from the regulator output that connects to the ammeter. It is this wire that I touch to the generator output. Once polarized, the generator charges the battery as expected.

I think I have a suitable diode somewhere in the garage to replace the regulator for testing. The original cut-out was stuck and I think this is what burned out the original generator.
 
You said you replaced the genny. It may have the field coils reverse wired. Loosen the fan belt, remove the wire from the cutout /regulator and touch the battery lead to the output terminal. The generator should motor in the same direction as the engine runs. If it motors in the opposite direction it is depolarizing itself every time you stop it or disconnect the load.
 
So, with the new generator and cutout/regulator all was well for 7 years, then you recharged the battery this spring, and now it needs to be polarized each day.
How old is the battery, and how well does it test for function?

If the battery is fine, then do as Katy said in #4.
 
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Thank you all for the suggestions. It will take me some time to get to a fix as family matters are intruding.

I will try to remember to post the solution when it occurs.
 
"So, with the new generator and cutout/regulator all was well for 7 years, then you recharged the battery this spring, and now it needs to be polarized each day.
How old is the battery, and how well does it test for function?"

It is actually possible to charge a battery that is very low or dead backwards. I should know I have done it.

Is there any possibility this happened this spring?
If the ammeter needle moves in the correct direction with lights on etc then this is not the case.
 
I think Mitch go it. The VR is shot.

I did not initially notice, but when I get the generator charging, it is charging at a constant 10 amps that the third brush is set for and does not drop over time as expected. Turning on the headlights reduces to charge to close to zero. I.E. the VR is not working as advertised. I will check out the battery to ensure that all is well with it and then bite the bullet and replace the VR.
 
I would suggest using a voltmeter to determine for SURE what is wrong before you start replacing stuff. Test voltages on the battery, on the VR output, and on the VR input, all in reference to gnd. Do this with engine running and not, post the numbers. That''ll tell a lot.
 
Hi all, as promised, I am trying to put an end to this thread.

Over the past week we have undertaken four short club runs to local senior residences. At the start of the first run, I had to polarize the generator to get it working properly. On the subsequent two runs, it retained its polarity and the ammeter flickered mainly on the positive side but when I hooked a battery tender, it charged for an hour or so. Today, the ammeter remained positive on a three hour run in city traffic and when I hooked up the battery tender when we got home, it showed the battery to be fully charged.

I have no idea what is happening, but I am not going to fix what ain't broke. Thank you all for your interest and advice, I am going to leave well enough alone.

You have given me enough to work with should the trouble reoccur.

Thanks again
 
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It could be a poor wire connection, such as where the field coils wire ends are twisted together and soldered (hopefully soldered). I worked on a powerhouse generator and had to solder the base of the ground brush post to the frame it was riveted to. Even though the post was tight and looked good, it wasn't making a good electrical connection until I scraped it clean at the base of the post and frame, then soldered it. Actually I soldered both ground posts, as it was a 5 brush powerhouse.

If you have to solder this post, it takes a lot of heat and you want to get it soldered quickly and take away the heat before it messes up the bakelite. My WEN 250 does a good job for this and also for the heavy copper terminal on a starter contact.
 
I think I finally got the problem licked.

The issue became more and more problematic and with the help of a club member the generator was thoroughly tested and found to be in good condition. The voltage regulator was replaced with a diode cut-out and the problem was not fixed.

Finally, earlier this week when I started the Tudor for a run, the lights and horn did not work in my pre-run testing. A quick check through the wiring revealed a very loose connection at one ammeter post. No problems since tightening it.

Thank you all for your help.

Regards

Ian
 
Loose or corroded connections at the terminal box or ammeter are one of the top electrical problems. Out of sight.......out of mind.
 
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