Another Ammeter Question

M

MaineDad

Well-known member
Guys,

I have a question regarding the ammeter on my 52 Cub. It shows a discharge when the ignition switch is pulled out, but when the tractor runs, it just stays at zero with no movement. When the lights get turned on, it shows a discharge. It has a new VR and rebuilt generator. The ammeter looks newer too.

Thoughts?
 
Your ammeter sounds fine. The problem is in the charging system. Ground the F terminal on the generator and see if the ammeter indicates a charge. If it does, your problem is in the regulator. If it does not, the problem is with the generator. Did you re-polarize the generator just to eliminate that as an issue?
 
Can you polarize the generator with the hood on? It looks like the terminals are on the back side of the VR.
 
If you are careful.... I use a piece of wire with the ends barely stripped. The terminals on the VR are the center one on the side with 3 and the other side.

EDIT: you can get at it from underneath the VR, look carefully and you will see the metal the terminal(s) are connected to and that will work too.
 
Update: I grounded the F terminal as BD suggested and the ammeter showed a charge, so that would indicate that the VR is bad. I removed the VR, which was new about 7 months ago, and re-did all the connections. I started it up again and no charge on the ammeter :(

So my questions are why is this new VR failing so soon and can I ground the F terminal again and use it as is until I get a new VR?

Thanks,


Micah
 
First of all, a lot of the voltage regulators being sold today are junk. They do not last very long. Good voltage regulators are available but expect to pay about twice the price of the cheap ones. (well worth it in my book)
Now, as far as grounding the field and operating - if you use the tractor for work where it runs for an extended period of time you run the risk of over-charging the battery. You might be better off to run from the battery and re-charge periodically or between uses. They will run quite a while on a fully charged battery.
 
Went to Napa this morning and bought a new VR. They had two in stock at $38 each and yes they were American Made!

Installed it and taaadaaah we have charging again. The needle is kind of bouncing though. Anything to worry about? It also had a resistor that is used on the F terminal.
 
OK - so I had to ground the F terminal again on the VR because it stopped charging again. The recently installed Napa VR that was made in the USA seems to have gone bad too. Could something else be causing these VR's to go bad?
 
Unfortunately - most of the time it is just poor workmanship even on the low end American made ones. I think a lot of the components from the cheap ones are sourced offshore. There really isn't much of anything in the system to make them go bad.
 
Thanks BD. I do have one question regarding the Napa VR I installed. The instructions said to maker a new lead between the "Bat" terminal of the light switch to the "L" terminal of the regulator. Now the original wiring diagram for the tractor shows the "L" terminal being connected to the Ignition switch, not the ammeter, so I did not make the instructed new lead. Was I wrong to do so?
 
As long as the ignition system works and the charging system works - leave things alone.

It really doesn't make any difference where the ignition feed comes from, the amp guage or the L "load" terminal of the voltage regulator.
 
Something that was a problem on my '51 was the fact that the steel plate the voltage regulator bolts to was not well grounded. The ground connection the voltage regulator uses is thru one of its mounting legs. You will see a copper braided wire along the left side of the voltage regulator. The is connected to the left side (on voltage regulator) mounting clip (part of regulator). You can check with a voltmeter between this ground braid and any good ground point on the tractor. If you measure any significant voltage (tractor running) , your ground reference for the voltage regulator is poor.

Paul in NJ

1951 Cub
Cub -22 mower
54A blade
Woods 42
 
Minor point that may help others. Grounding the F terminal on the generator and having it show a charge does not indicate that the VR is defective, it tells you what is working but not what is not working. It tells you that the generator, meter and wiring to the battery are good but what is bad could be several things. The VR, wiring from the generator to the VR, and the VR ground can all cause the problem. The wiring to the VR field terminal and generator F terminal is easy to check, the ground on the VR should be easy to check. If those 2 are good then the problem should be the VR. Checking the wiring first may save the cost of a not needed new VR.

I had the same problem as did Paul in NJ on my 154. Needle bouncing and poor charging. Grounding the F terminal showed a charge but the actual problem was a broken bonding wire as Paul described between the VR and the mounting tabs on the VR. Grounding the F terminal gave a partial ground through the field resistor and allowed the VR to function.
 
Running a short braided or stranded lead from the voltage regulator base to a known good ground might be worthwhile to insure good grounding for the regulator.
 
Well guys, I removed the hood today to see if I could check all of the wiring and ground connections. I removed the generator and VR and completed sanded the brackets and base;

GenBracket.jpg


ground.jpg


I checked every single wire and every connection. I actually removed the braid that held all of the wires to look for shorts etc. I cleaned every connection and replaced a few that looked bad. I then double checked the wiring diagram, wire by wire, to make sure everything was correct. Put it all back together again, and still no charging unless I ground the F terminal. I even polarized the generator after it was all back together too. I guess I have to go out and buy my 3rd VR in just a few months? Very frustrating...
 
First, if you have the storage space, hold on to the old regulators. They may have application, I may be interested in one of them. Below is the email for a fellow, Bob Jeffers, who does electronic conversions of regulators. I have not done business with him, but have seen several references to his conversions, all of them positive comments. If you will post the numbers on the plate on your generator, I will post the maximum rated amperage which is one of the things he will want to know.






bobj50@comcast.net 603-654-9852
 
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