Miswired F640

[Baysweb01]

Hello All:
New member with my first query. I recently acquired my father's 1956 Ford 640 from my brother prior to his death. I brought the tractor home and it seemed to run fine for about a week. Then it started running very rough. I discovered the points were locked up and replaced those and re-timed it. Thought all was good.

Then I noticed the battery was boiling over almost immediately after being started. Not a good thing. I began tracing wires. I have a voltage regulator with L, BATT, & F terminals on the side and I assume A terminal on the bottom. It was wired with the gen A term to the bottom, gen GND terminal to F, gen Field term to L and BATT to the terminal block and then to the ammeter. My understanding this is all wrong. It should be A to the bottom lug, FIELD to F, BATT to the ammeter, GND to ground, and L can either be open or connected to lights and other loads.

I made the changes and polarized the generator by shorting the BATT and F terminals and got a really healthy spark. I saw conflicting information online on how to do this. Some said to short the BATT and A terminals instead.

However, now the generator does not seem to be "generating." I thing it was working before since the battery was overcharging. Is that just because it has not been "excited" yet since the battery is actually overcharged? Is my regulator fried from being wired incorrectly? Bad ground to the GND terminal? Or what?

 

[JMOR]

That is not they type of VR that was factory on a 640. I don't know what generator you have, but if it is factory, I would say that the wiring you described as well as what would be an incorrect polarizing attempt resulted in a ruined VR.

 

[Baysweb01]

I do not see any manufacturer marking on the generator. It appears to the the original. Photos attached if that will help. The tape on the wires are my tracing markings. Someone spray painted the tractor, and all the wires are painted red.

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[JMOR]

From the looks of it, probably factory or an equivalent truck/auto generator of the same time period. That would make it a Type-B generator, meaning that power is supplied to Field for full output....& as it was wired, with gen Field tied to VR L-terminal, it was being full-fielded 100% if time, thus overcharging battery. Now the bad....with Ground tied to the VR Field terminal, that makes the Field contacts try to supply voltage into ground (fundamentally a short circuit), thus burning up the field contacts of the VR. If that didn't kill the VR, then trying to polarize by applying battery voltage to the VR Field terminal means that such current would be many times the rated current for those contacts (think 50 to 100X). You say, why? Because doing so not only supplied power to the Field, but due to VR internals/contacts, current will also be applied to the very low resistance armature by way of Field contacts, a very high current! Poof!

 

[Baysweb01]

JMOR, thanks for the responses. I did disconnect the Field lead from the VR before attempting the polarization. But I understand that the previous wiring likely did damage.

My primary concern is the generator since it appears original and I want to keep it. Would it have been damaged in all this?

I have seen where I can test the generator. If a B type, I apply 12V to the Field terminal, rev up to approx 1500 RPM, and measure the A term for 13+V. Is this the proper test?

 

[JMOR]

(quoted from post at 12:46:55 05/18/23) JMOR, thanks for the responses. I did disconnect the Field lead from the VR before attempting the polarization. But I understand that the previous wiring likely did damage.

My primary concern is the generator since it appears original and I want to keep it. Would it have been damaged in all this?

I have seen where I can test the generator. If a B type, I apply 12V to the Field terminal, rev up to approx 1500 RPM, and measure the A term for 13+V. Is this the proper test?

es, that is a decent test and the longer you run it like that , the higher the battery voltage will go. I have seen 12v batteries go as high as 17v....not good for battery,

 

[Baysweb01]

I am having trouble locating a B-Circuit VR with screw terminals. Any suggestions?

 

[JMOR]

(quoted from post at 22:26:23 05/21/23) I am having trouble locating a B-Circuit VR with screw terminals. Any suggestions?

f you can find a real parts counter man (not a kid with a computer), he can probably find one that is at least close enough to work from vintage Ford cars around 1940's era. Best bet is locally owned parts stores, not Advanced, O'Reillys, Autozone types.

 

[Baysweb01]

Yeah, I know.... Went into Advanced about a year ago to buy some points for my 69 Camaro. The young man behind the counter had no clue what I was talking about to even begin to look it up on the computer. Not being critical.... just stating a fact.

Unfortunately, I don't know of any privately-owned parts stores in my town. The big box stores have put them out of business.

For the record for others who may encounter this problem: If my research is correct, the OEM part numbers for a 3-terminal (ARM, BATT, FLD), B-circuit, 10-12 amp VR are GR278 or C0NF-10505A. Purchasing a VR that is "compatible" with these should work. I found a few online such as Steiner Tractor's ABC1164 and Rare Electronics 231-14007. I ordered one. We will find out in a few days.