Checking continuity with a voltage regulator

I have just finished reassembly on a 1957 Cub LB with a 6v generator and Delco Remy VR. I have no spark. Tractor ran before disassembly and painting.

I am performing a continuity check to see if I have maybe missed a connection or compromised a ground with paint. I have a good strong battery with a fresh charge. Full voltage measured at battery, starter, both sides of ammeter, and the "battery" terminal on the VR. The "F", "L", and "GEN" terminals do not register. Using the schematic in the back of the service manual, it would seem that there needs to be current at the "L" terminal which would then energize the ignition switch thence to the coil...etc.

Not completely understanding how a VR functions makes it a little hard to continue. I was wondering if someone could provide a simple explanation of how the VR works (keyword:"simple")? Does anyone have a schematic for my VR? Any help appreciated.

The L terminal is not connected to the Bat terminal, it is only energized when the Generator is charging (it kind of bypasses the battery to give lights more power (a generalization))
The ignition switch (assuming it is a distributor/coil system) should havwe a wire going to the load side of the amp gauge, where the Bat wire is attached. Jim

When it is not running, there is no voltage or continuity between the Bat and Gen terminals. Thus it is OK. There is also no connection between the F terminal and anything but the regulator ground and the Gen F terminal. They are very separate on the inside. These Type A circuit generators get field voltage internally and ground the field to make adjustable output. Jim

Jim, thanks for the reply. The first point of interest in your response is about the wire going from the "+" side of the ammeter to the hot side of the ignition switch. Hopefully my schematic will come up on the post here. There is no jumper on the schematic. Are you saying that I should run one from the "+" side of the ammeter to the (green wired side) of the switch? That would provide constant voltage to lights and the "L" terminal of the VR if I am reading it right. Right?
Cub Schematic

Let's try again with the schematic...

With the engine running you should measure out-put volts at the gen terminal if the gen is charging.

That was going to be one of my first questions when I get it running. Currently I am in the "getting it running" part of the game. Actually the fun part from my view. I like diagnosing starting issues. Just in untested waters with the VR is all.

From what I can assess the L terminal should be hot at all times Running or not. If it is not, then Running the lights and ignition from the Non battery side of the VR should not be a problem. I would not connect the wire from the L terminal to the Lights if I were to rewire it like this. Jim

OK sorry, you lost me. The wire from the L terminal connects to the same post as the wire that powers the lights. That is pretty much a done deal. My question is as follows:

You mentioned a connection from the ammeter to the hot side of the ignition switch (this would be same side the L terminal and light switch are connected). There is no such wire on the schematic near as I can tell. Is this an error on the schematic do you know?

The first thing you need to do is disregard Janicholson's pontificating and look at your diagram. The BAT and L terminals are joined together inside the regulator and they are both HOT at all times whether the tractor is running or not. This is obvious by looking at your diagram. If the L terminal which feeds both the lights and the ignition switch was not hot with the tractor off, the tractor would never start and the lights would only come on when running!

If you have a voltmeter or test light the B and L terminals must be hot as well as both ignition switch terminals(with the switch on of course), and the negative side of the coil. Check this by following your diagram Report back your findings. The plus side of the coil should be no volts with the points closed and six with the points open. Be sure to check this before you report back.

Yo Jim, Sure you dont wanna re think your statement:

The L terminal is not connected to the Bat terminal, it is only energized when the Generator is charging (it kind of bypasses the battery to give lights more power (a generalization

If you go up to a tractoR that uses a 4 terminal VR witH the (L)oad terminal and turn the lights or ignitio ON the lights work and the tractor starts and thats BEFORE THE GENNY CHARGES AND EVEN IF IT DONT CHARGE

John T

here is a link to an old Delco Remy regulator manual explaining operation of the 4 terminal regulator

http://chevy.oldcarmanualproject.com/electrical/49dr324/1r11102.htm

First of all, lay off Jim. Without his help and patience over the years I would have had to give up this pursuit long ago. Mind your manners and act your age. You don't have the excuse that some of the younger forum participants have.

Second...I AGREE with you which is why I am asking Jim for clarification. The schematic clearly would indicate a flow of electricity from battery to starter to ammeter to VR-BAT to VR-L and right back up to the ignition switch. We will sort this out but I am going to need someone beside you to assist me. Your references won't hold up to examination...Jim's do.

Dave, Heres the real deal:

If the ignition switch is fed its hot voltage off the L terminal on the VR and thats NOT hot, SHE CANT EVER SPARK OBVIOUSLY.

There MUST be hot battery voltage present on:

BOTH sides of the Ammeter,,,,The BAT terminal on the VR,,,,,the L terminal on the VR (contrary to a post below). The L terminal is what feeds hot battery voltage to loads lights and Ignition EVEN IF TRACTORS ISNT RUNNING AND EVEN IF GENNY ISNT YET CHARGING

Okay, you ask for a VR Diagram, here is one:

http://chevy.oldcarmanualproject.com/electrical/49dr324/1r11102.htm

To see if the VR is the problem (L should be hot and if not she cant fire) feed the ignition instead off the Load (NOT battery/starter) side of the ammeter n see if she fires then?????

On tractors that used a 3 terminal VR that didnt have the Load terminal, loads like lights and ignition got fed off the load side of ammeter. Thats the same (load) side of ammeter that wires down to BAT on the VR, the ammeters other Supply side wires to the battery.

If you wanna still use that VR thats bad cuz the L isnt hot, just unhook the wire off L and wire it instead to the load side of the ammeter (or even over to BAT, same thing electrically). the its working just like a 3 terminal (NO L) VR with loads fed off ammeter. If L works (always hot) then Id use it as it regulates a bit better

If still no spark run my Troubleshooting Procedure:

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

Got it?????????? If no voltage to L and ignition is fed off L: NO FIRE,,,,,Try to feed ign switch off ammeters load side or VR's BAT n see if she sparks???

Let me know, Im on and off aS iM ON THE ROAD IN MY rv IN fLORIDA but I will eventaully get on

John T
John Ts Ignition Troubleshooting

I appreciate the link very much. Am I wrong or does that conflict with the tractor schematic as it does not show a connection between the BAT and F terminals. At least now I know what F stands for.

John, I was hoping you would show up at some point! Looking at the schematic for the VR, it would appear that I DO need a short wire from the ammeter to the ignition switch, am I right?

The ignition switch MUST HAve hot battery voltage from somewhere !!!!!!!! Otherwise it sure cant feed voltage to the coil to make a spark. Sooooooo if L on the VR isnt hot, feed loads (lights n ignition) instead off the load (NOT battery/starter) side of the ammeter and dont use L on that dern VR. The BAT terminal on the VR is electrically almost same as the Load side of ammeter (thats where it wires to) ya know...

See my post above and theres a 4 terminal VR diagram linked. Jim is a good man n gives good advice also, we usually agree but NOT this time about L on a VR not always being hot, I stand on my post L IS ALWAYS HOT see my diagram and teh link the other poster noted TO EXPLAIN HOW L ON A VR WORKS

Best wishes

John T

I misspoke in my first post. There is supposed to be a near direct connection between the L terminal and the Bat terminal inside the regulator. Thus the L terminal should be at battery voltage all the time. My second post and John Ts are correct.
There is no connection between the F terminal on the VR, and the Bat terminal. The F terminal on the VR grounds the field windings in the generator. These windings get their electricity from being connected to the third brush in the generator, or are directly connected to the Armature post of the generator.

I do not know why you are not finding battery voltage at the L terminal. I would suspect the VR has internal problems, if the fault is not visible from the outside.

Jim (and thanks for your support)

Thank you and you are welcome at the same time!
Just consider the source.

Geeeeee Jim, my fingers get ahead of my old brain is why I mess up BUT YOURE NOT AS OLDDDDDDDD AS ME YET LOL Luckily I dont have All Timers, I only have Part Timers so far grrrrrr

Heres Jim Beckers post I saved about 4 Terminal VR operation, until then I knew how they worked but didnt have a pic handy, now i do thanks to Jim

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=776571

John T

OK John, thanks! I'll print this out and take it out there with me later. Time to go up to the school and watch my daughter play b-ball. I'll post back later.

No, there is no conflict.

The diagram in the link shows a schematic of the internal circuitry of the regulator.

The tractor schematic shows the regulator in what is called a "block diagram" which gives just the external connections.

I just want to chime in and say that this is a great discussion. I hate mechanical voltage regulators. Eventually the points stick and I find a dead battery when I want to use my H. The link to the old Chevys site was also very good.

Thanks

Greg

Overly simplified explanation is that the voltage regulator varies the "grounding" of the field circuit according to battery voltage. The lower the battery voltage, the more direct the grounding becomes, usually through a 6 or 7 ohm resistor under the regulator base & the vibrating field relay/contact inside.