Generator Pegs Ammeter!!

I am still working on our W6 with the generator problems. I will go through the steps of what I have done:
Original problem:Gen Wire came off of regulator and hit frame.
Solution:Got new Regulator and had generator rebuilt. Disconnected battery, installed assembly, reconnected battery, jumped batt and gen terminals with wire to polarize
Behavior:Would only reach the zero line at full throttle, otherwise drained.
Solution: Sent generator and Regulator back to repair shop
Behavior: After getting it back I disconnected battery,installed assembly,reconnected battery, polarized by jumping batt and gen terminals, Drained regardless of engine rpm or light switch settings
Solution: Sent generator and Regulator back to repair shop again.
Current problem: After getting it back, the gauge sits at zero when engine is off. Gauge is functioning, as it deflects when the lights are turned on. When tractor runs, ammeter is pegged at 30 amp DRAIN. Tried repolarizing, but has no effect. Tried switching to another old regulator that I cleaned the points on, did same thing, but when the tractor was shut off, it continued 30 amp drain until battery was disconnected (took about 2 sec to disconnect the cable)(I assume that means the points are stuck in it.) The guy at the repair shop told me it works fine with negative ground, but doesn't with positive ground on his machine. He suggested I reverse the electrical system of the whole tractor, which I told him I wasn't interested in doing. What the heck is causing this, should I just buy a new generator and regulator or go to a different rebuilder? The guy at the shop told me that he won't looking at it again because it can't be on his end. At the same time, I don't want to have to eat the cost of the rebuild and a new generator. Input Please?

Note: Some 4-terminal voltage regulators have the "Gen" terminal molunted on the bottom with "F", "Bat" and "L" terminals in a row along the side.
"GEN" on VR should go to "A" on Generator.
"F" (or "Fld") on VR to "F" on Generator.

I think that the worst you could have is some contacts in the VR possibly heat damaged and not closing or stuck together. You might be able to clean them up and be back in normal operation.

Took the gen off and sent it to be tested, tests great they said, no problems.

In the process they wire brushed some of the paint off the case to where the F and A terminals (if I remember right...was 10 years ago) had been stamped into the case.

Bottom line is the F and A wires were reversed by the previous owner and once set back correctly, it worked perfectly. I believe what was happening was the generator field was connected to the battery and it just slowly drew down the battery as the tractor was turned on.

Voltmeter was showing a mild discharge under normal conditions, it went back to showing full charge after the wiring was properly reset.

1 - Run a temporary ground wire from the grounded battery post to the regulator base (not to the regulator mounting base but to the metal relay frame.) Now run the tractor and see if it charges. If it does, arrange some sort of permanent ground connection to the regulator relay frame.

2 - If the above doesn't help, with the engine running at speed first ground the regulator "FLD" terminal. Then jumper the "BAT" and "ARM" terminals at the regulator (this connection may carry 15 amps or more - expect a bit of a spark!).

If jumpering causes the generator to charge it's time for a new regulator. If it does not, the problem's with the generator.

Nowwwww I know thats a lot of disclaimers and unknowns but I cant say for sure what happened. One GUESS is the genny really didnt get properly repolarized at your ground (if it was opposite from the repair shops) and when you fired her up the VR lost its smoke n marbles so nowwwww w is why shes NOT working????? ?????

When you polarized did you get a small spark????? ??? IF NOT she wasnt wired or polarized correct and you may have, therefore hurt the VR cuz the genny wasnt at the same polarity as your tractor????? ? To be safest when polarizing you may wanna be sure the gennys Field post is dead grounded in case it isnt getting a good ground via the VR as it nornmally should. BOTH the genny and VR need a good ground !!!! sure BOTH are??? Anywho if you dead ground the gennys Field post and temporarily jump/spark a hot ungrounded battery voltage feed (should be ovailable on the VR BAT terminal if shes wired correct) direct to teh gennys ARM post she ought to spark n you know shes polarized. If alls wired correct that SHOULD happen when you flash the VR's BAT and ARM terminals together buttttt t if no spark its NOT polarized cuz maybe a bad ground or not wired correct.

At this point I would polarize n be sure its done right and you get a spark..... ....then if no charge dead ground the gennys Field post (when running) n see if she charges then ????? ??? if NOT leave the field grounded n jump the VR's BAT and ARM terminals together n see if she charges then????? If so the VR's cutout relay must not be closing or teh genny is bad cuz with teh field grounded and the cutout relay by passed you have taken teh VR functiosn out of teh equation n if still no chARGE THEN GENNY IS BAD OR SHES MISWIRED????

I DOUBT THE GERNNY IS BAD MORE LIKELY ITS THE WIRING OR VR

Sure the ammeter is wired correct polarity???

Correct, that peg to dischaerge when shes shut down sounds like the VR's cutout relay is stuck closed !!!!! !!!!! assuming the ammeetr and all else is wired correct???

This is wayyyyy more then you need but heres my troubleshootign procedure for non charging, this repeats much of the above but i fear the VR is bad cuz the genny wasnt correctly polarized to the tarctor or else its good for ONLY one ground?????

TROUBLESHOOTING CHARGING SYSTEMS

ARE YOU SURE THE AMMETER IS WIRED CORRECT AND WORKS????? If you turn the lights or ignition on (if coil ignition not a mag) when she’s not running, the ammeter should swing over to the - discharge direction, does yours??? Are BOTH the ammeter terminals reading hot battery voltage?? They MUST !!!!! ! There’s but one wire on the ammeters Supply (from battery/starter) terminal while its other Load terminal wires to the BAT terminal on a Cutout relay or VR PLUS wires to feed loads like lights or ignition, unless where a 4 terminal VR is used where lights n ignition are fed from the LOAD terminal on the VR.

To Polarize the Generator, first temporarily dead ground the Gens Field post to case/frame, then momentarily flash jump a wire from the Cutout Relay or VR's "BAT" terminal over to its GEN (or ARM) terminal and you ought to get a small spark. Same things accomplished by momentarily flash jumping a hot wire (BAT terminal on Cutout Relay or VR or starter post etc) direct to the Gens ARM post to get the spark.

TROUBLESHOOTING A CHARGING PROBLEM IN CLASS A DELCO TYPE SYSTEMS

1) For a good working Gen to get to and charge the battery, it has to have a path usually from the Gens ARM post,,,,, ,,,,to and through the Cutout Relay (between its GEN and BAT terminals, regardless if on a VR or Relay),,,,, ,,,up to the Load (NOT to battery) side of the Ammeter,,,,, ,,,to and through the Ammeter,,,,, ,,,,from BAT side of Ammeter to ungrounded battery terminal, often via the starter lug post. Is yours wired that way or equivalent ??? The ammeter should read hot battery voltage on BOTH terminals, does yours??? Even if an ammeter were stuck (but still continuous) as RPM increases the battery voltage should rise from 12.6 to near 14 volts and/or the lights glow brighter (half that on 6 volt systems). Have you tried that in case the ammeter isn’t working right?????

2) If the above is so, the BAT terminal on the VR or Cutout Relay MUST ALWAYS READ HOT BATTERY VOLTAGE. Does yours??? If not, the Gen cant get to and charge the battery.

3) The Gen to VR (if it has one) wiring is as follows:

BAT on VR to ammeters load (NOT battery) side

ARM (or GEN) on VR to Gens Armature post.

FLD on VR to Gens Field post.

(L) Load (if you have a 4 wire VR) up to BAT supply input terminal on switch to feed loads like lights and ignition.

WIRING ON CUTOUT RELAYS: They wire BAT side to ammeters Load terminal,,,,, GEN side to gens Armature post. On cutout relay systems, the Gens Field post is wired to the light switch where it gets a dead ground for high charge or a resistive ground for low charge. Therefore, there must be a good connection from the Gens Field post up to the switch PLUS the switch is good and it’s well grounded !!!!! !!

4. THE GEN AND VR OR CUTOUT RELAY MUST BE WELL GROUNDED AND THE BELT GOOD N TIGHT. If any doubt, run a ground wire from the grounded battery post or clean solid frame member direct to the Gen and see what happens????? ????? ????? ????? ????

NOW, if the Gen and VR are grounded,,,,,all is wired correct,,,,, ,,BAT terminal on VR or Cutout Relay is HOT,,,,, ,,Belt is tight,,,,, ,,,Ammeter is good n continuous n works but she wont charge, have you had the batteries tested lately????? Is there electrolyte above all the plates and no cells have a gray or milky appearance????? A bad battery may not accept a charge you know!!!!! !! If the battery checks okay, proceed below to see if its a Gen or VR problem (AFTER you have insured the wiring per the above)

TO DETERMINE IF ITS A GEN OR VR OR CUTOUT RELAY PROBLEM

5. a) VOLTAGE REGULATOR SYSTEM: With the tractor running, temporarily ground the Gens Field post to case. If she charges then but NOT otherwise, the VR may be bad, or a wires missing from VR's Field post to the Field terminal on the VR, or the VR isn’t well grounded.

b) IF IT’S A CUTOUT RELAY SYSTEM and she charges only if you dead ground the Field but NOT otherwise, its either a bad switch or the switch isn’t well grounded or else the wires bad or open from the Gens Field post up to the switch. INSURE THAT GOOD SWITCH GROUND AND WIRING

6. If she still don’t charge, leave the Field grounded and jump a wire across from the VR or Cutout Relays BAT terminal over to its GEN terminal (jump by passes the cutout relay) and see if she charges. If then but not otherwise, a VR's cutout relay isn’t working correct (maybe points burned/carboned) or a Cutout Relays NOT working or not wired correct.

7. With the 2 steps above, you have basically by passed the VR or Cutout relays functions, so if she still don’t charge, you're left with a bad battery or wiring or the Gen itself.

8. MOTOR TEST. You can Motor test the Gen. If its grounded and you remove the belt and apply hot battery voltage direct to its ARM Post and have the Field Post dead grounded to frame, it should motor n run well (Armature n Brushes and Commutator likely okay). Then, if you next remove the Fields ground and it speeds up some, the Fields probably good. If it passes both those tests, it should charge, and if not, it may be a wiring or battery or grounding problem. The hot battery voltage may be taken off the VR's BAT terminal or the starter post or the battery itself for this test.

9. Typical Gen problems may be the brushes are worn down or the hold down spring assemblies are stuck/corroded/dirty and arent pushing the brushes tight down against the commutator. Check those things out. Worse may be bad fields or armature etc. Air and WD 40 etc can clean and free them, the hold downs must be free n snap and hold the brushes DOWN TIGHT and they cant be worn down too low.

SUMMARY: Check the wiring,,,,,the grounds,,,,, insure BAT on VR or Relay is hot,,,,, ,check battery (maybe load tested and Specific Gravity checked),,,,, ,,,good tight belt,,,,, ,insure ammeter is continuous (BOTH sides HOT),,,,, see if battery voltage rises above 12.6 (half that for 6 volt system) and/or light glow brighter,,,,, ,,,do the Field and cutout relay VR by pass checks,,,,, ,,insure the Gens brushes arent worn down and the hold down springs are free n clean and push the brushes down tight,,,,, ,,,,,check the connections,,,,, ,,,try the Gen Motor Test to see if its good.

You may just have a bad battery or bad ground or connection if the Gen and VR or relay are okay. Good Luck n God Bless, let us all know.

John T Nordhoff in Indiana, retired electrical engineer who usually lurks over on the Mother Deere pages instead of over here on the "dark side" lol

Do that failry simple test I posted above (dead ground field then jump BAT and GEN on VR together) to totally by pass the VR functiosn n see if even the genny will charge now cuz if not Im afraid ITS FRIED ALSO????? ???

THAT will show if the gennys is good or bad PERIOD

John T

1 – The 30 amp discharge after shutdown with the old regulator says the regulator’s cutout contacts are not opening. The regulator is indeed no good – throw it away!

2 – The 30 amp discharge with the new regulator and the engine running says the generator is providing current, but that the generator polarity is reversed. Are you certain you are polarizing correctly? (With all wiring and the battery connected, and everything shut off, momentarily jumper the BAT and GEN terminals at the regulator. You should see a small spark when the jumper makes contact – as soon as you do the generator is polarized….)

3 – The fact the generator/regulator work OK on the test machine when negatively grounded says both parts are functional. But why the guy at the repair shop says it only works on positive grounded is a bit puzzling. (On the test stand and when properly polarized, a generator/regulator SHOULD work equally well both negative and positive ground .)

I figure either the repair shop guy doesn’t know what he’s doing, or possibly the new regulator has a diode in place of the traditional mechanical cutout relay, and the diode is arranged for negative ground. Ie. the regulator works only grounded negative. (If this is true the regulator is should be clearly marked “NEGATIVE GROUND ONLY” or similar)

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Probably your quickest/cheapest solution is to simply reverse the ground polarity on your tractor. All you need do is swap the connections at the ammeter, then reverse the battery cables. (If you are a purist you can also swap the primary connections at the coil but it’s not really necessary)

Good luck, and post back what you find!

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"But why the guy at the repair shop says it only works on positive grounded is a bit puzzling."

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I meant to type this:

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"But why the guy at the repair shop says it only works on NEGATIVE grounded is a bit puzzling."

1 - If the existing ammeter terminals are so corroded they risk breaking off it's probably time for a new ammeter! ($20 or so...)

2 - Regarding the 30 amp discharge changing to a 30 amp charge if you flip the battery, keep this in mind:

Operating with the polarity reversed causes the generator's output voltage to ADD to the battery's voltage when forcing a discharge current. This high level of discharge is indicated by the ammeter pegging at -30 amps.

However with the polarity correct the generator voltage opposes battery voltage. Now when generator voltage slightly exceeds battery voltage, the generator forces current back the opposite direction and charging takes place. Thus 10 - 15 amps of charge will be the maximum and which the ammeter will indicate.

I don't see how messing up the rebuild can cause polarization problems. Only way I can figure to do it is to refit the generator with permanent magnet field shoes (pretty much impossible!)

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I guess if it were me I'd swap in a new ammeter, change the system polarity to negative ground then be done with it!