Flashing a gen...running or not?

Excellent info here on this board. I have read lots of genny questions answered by John T and Clooney and have one more question for you boys.

When flashing a gen, do you do it while it's running or at a stand still? Can it be done with the genny still connected to the VR?

Thanks for the help.

Paul

To answer your question, the Gens Field post needs a ground return path, and thats via the VR THEREFORE the VR requires a good ground itslef which is usually via the Gens case and it must, therefore, also have a good frame gtound connection.

I will cut n paste my Standard Charging System Troubleshooting Guide: This is for Class A Delco type charging systems NOT for Class B Ford type.

TROUBLESHOOTING CLASS A CHARGING 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 output,,,,, ,,,,,to and through the cutout relay portion of the VR (between its ARM and BAT terminals),,,,, ,,,up to the Load (NOT to battery) side of the Ammeter,,,,, ,,,to and through the ammeter,,,,, ,,,,from BAT side of ammeter to ungrounded battery post, 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. Have you tried that in case the ammeter isnt working right????? ?

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

3) The Gen to VR 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 ingition.

4. THE GEN AND VR 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 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 she dont, 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 PROBLEM

5. With the tractor running, temporarily ground the Gens Field post to case. If she charges then, the VR may be bad, or a wires missing from VR's Field post to the Field terminal on the VR, or the VR isnt well grounded.

6. If she still dont charge, leave Field grounded and jump a wire across from the VR's BAT and ARM terminals (jump by passes the cutout relay) and see if she charges. If then but not otherwise, the VR's cutout relay isnt working correct (maybe points burned/carboned/resistive)

7. With the 2 steps above, you have basically by passed the VR functions, so if she still dont 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, it should motor n run well (Armature n Brushes and Commutator okay). Then if you ground the Field and it slows down some, the Fields probably good. If it passes both those tests, it should charge, and if not, it may be a wirign or battery or grounding problem.

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. Chekc 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.

SUMMARY: Check the wiring,,,,,the grounds,,,,, insure BAT on VR 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 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 you say the Gen and VR are okay.

Good Luck n God Bless, let us all know.

John T Nordhoff in Indiana, retired electrical engineer

Well, I answered my own question. I just did while it was not running and now I have output again but now..... I can't get output from the regulator. Have a look at the schematic of the standard 3 coil regulator here, and my question is, where does the field winding get its' ground connection to turn on? I can get good output from the regulator if I disconect the field wire from the reg and ground it, but if I leave it connected to the VR (voltage regulator) and then ground the field, I get nothing, no output. I have several different regulators of the same construction and none of them seem to give me any output.

Help! please :-)

Cheers

Paul

• DC genny regulator

Wow! See, I knew someone would have an explaination. It sure was a dome scratcher for a few days for me. I didn't know the difference between the 2 and it's quite amusing (now) that I ended up with 2 more Class B regulators to play with which would never have worked anyway. One was from a tractor of unknown origin and the other was a RB340 from a 60's Healy 3000. Maybe they were meant for positive ground??

Anyway, thanks for your help. I did give up on the genny on Thursday and I went to the wreckers and bought a Pontiac Firefly alternator and put that in in a half hour. Wow! What a difference. 35A out at 14.5VDC with the lights on!!

Thanks again boys!

Paul

As to the grounding...First test is from the actual base plate of the regulator to the battery ground (pos terminal in the VAC Pos ground system). You are really just ensurring that the regulator has a viable ground. (Regulators mounted on the generator have to ground through the generator mounting bracket which can have corrosion and high resistance. The field terminal ground test should also be to the mounting plate (assuming you passed the first test).

Email me I can send you a diagnostic from the Farmall Board that works for ours also

Paul f

Thanks for the input...I have been working on this thing for 2 days straight now and decided my time is worth more than trying to get the old DC genny working so I broke down and spent $20 on a Pontiac Firefly alternator. It fits perfectly where the genny was and only needs a simple 12VDC ignition wire to excite it and away it goes. 35A output which keeps up with the lights etc just fine.

For those of you who want to do the same, the Firefly alternator is MUCH smaller than the standard 10SI Delco alternator. This one is made by Nippn Denso and is a 1988 which still had a V belt and is about the same size as the genny and puts out lots of juice, even at idle. I also had to use one of my old 60's Pontiac muscle car alternator brackets to fit the top mounting lug but it was worth it.

I can post pics if anyone wants to see what it looks like.

Cheers for now.

Paul....now back to farmin'