Hey all, I took the truck out today to get some seat time before the snow starts coming down. No issues while I was out, but I did notice that the ammeter was showing more discharge than normal while waiting at stop lights on the way home. There was also a distinct lag before the ammeter would show charge again even after I started accelerating, and it would peg to full charge and then settle back into the normal range right away. I have had the same generator and regulator on the engine since 2007 and it has been dead nuts reliable, it may still be, which is why I need the deets on how to test the regulator correctly. Once I was back home I threw my multimeter on the regulator and got these numbers; - Armature showing 12.9 at idle, 14.7 - 16.1 at 1800 rpm - Field showed 13.0 - 14.3 volts at idle and would taper off to 9.3 - 9.7 when revved up - Battery showed 12.7 at idle and 14.7 - 15.1 when revved up -I took temp readings with the infrared thermometer as well, generator was the same temp as the engine which was 151*F or so after sitting for a bit while I grabbed everything, regulator came in at 106* F which is strange since it is mounted inside the firewall to the far left of the cab, fairly far away from the hot engine. There is not any type of insulation on the firewall though. I do recall the charging voltages in that range, but the reading on the field side are what's throwing me off, seems like the readings are backwards, should be sending more juice once the RPMs are off idle. The generator is a factory Ford 12v unit and the regulator is likely a Nieoff brand from over 20 years ago, I cannot remember and I peeled the label off for looks a long time ago. After sitting everything went back to normal and there was no lag between discharge and charge, it only happened twice, but I want to get ahead of a potential problem. I threw up some pics from the drive out to Red Rocks. Just need the proper procedure to see what might not be up to snuff. Thanks in advance.
Good deal, I was just considering they might just be starting to stick. The google machine is not being my friend about this, or I just suck at using the correct search terms.
As you rev the generator, you will see less voltage at the field as the regulator is modulating to control voltage at the higher rpm. On a generator you not only need to regulate voltage, you also need to regulate current. The three units in the voltage regulator are the cut-out relay, opens to keep the generator from trying to motor when voltage output is lower than battery voltage, such as idle. The other two units are the voltage regulator and the current regulator. You can tell them apart by the windings on the relay coil. The voltage regulator has a lot of turns of fine wire while the current regulator has fewer turns of heavy wire. So, what would cause the problem you described? If the cut-out relay is not closing as rpm comes up, the generator won't charge. If it closed late, you might see a surge of current and the ammeter jump way to the charge side. If the voltage or current relay stuck to the full field point, (both of these have two sets of points) you might see the same thing. In the 27 years I drove my 57 T-Bird I went through probably 3 voltage regulators. They all exhibited the same problem, the current relay became unstable. Some times it wouldn't close, so I had a no charge condition. The first two times I attempted to adjust the field relay with little luck. I'd get it to close at 12.7 or 12.8 and it would work for a while (sometimes only minutes) and then get to where it wouldn't close. The third time I just replaced the voltage regulator. At any rate, your description points to something causing the generator to go to full field. On a Ford generator you have to supply voltage to the field to full field it. Unless there is some odd short to power inside the generator, the only other way to supply voltage to the field it through the regulator.
Excellent reply, I just needed to know what each one of the coils do exactly and you provided that. I will pop the cover off the next time I wander out to the garage and give it a look over for anything out of sorts. Once I left the last stop light to when I got home everything was back to normal, I have a feeling that the age of the regulator is starting to show, I just hope the new ones available last as long if I need to replace it. Thank you.
Nick, if you’re going to replace the regulator at some point, I would look for an NOS one on eBay or what-have-you. 1956+. Atlas, Echlin and such. I have had terrible luck with new ones and the old ones have been spot on.
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