Ford 9N - discharging quirk ??!!!??

Hello- I have a quirky problem with my 9N electrical system, and am hoping someone will have had the same experience or can offer a solution. This is a fresh rebuild with a brand new harness, generator, and cutout. I believe all is connected correctly, and have checked that thouroughly. Tractor starts, and while cranking the ammeter shows slight negative, after starting shows positive with an increase when revved up. So far, so good. When I turn off the keyswitch, the ammeter goes 30A negative. I think this has to mean the cutout is sticking closed. So I replaced the cutout with another brand new one, same result. I think the generator is trying to "motor" from battery power. What would cause the cutout to stay closed, am I doing something wrong???
Any help is appreciated - Brian

Sounds like you've had a couple of "bad" cutouts, typical for today's parts from "the land of almost right".

You need for find a quality replacement cutout or go "solid-state".

There are aftermarket outfits catering to the antique Ford car and truck folks that sell OEM-looking units with a diode in them, a solid-state solution to the "stuck cutout points" problem.

Should be easy to find on GOOGLE.

Also, check over at the "N" Forum. Several guys there have built their own, gutting out the old cutout and installing a diode. ONE school of though uses 1/2 of a bridge rectifier, making the changeover part easy to mount.
Ford

Sounds like you need to get the Wiring Diagram out and double check how it's routed. Sounds to me that you may have a wire to the switch or the ammeter on the wrong post.

It's NOT a wiring error, so long as the cutout is in the line from the generator to the ammeter, with the exception that reversing the BATT and GEN wires at the cutout could cause the problem with it staying closed.

HOWEVER, as I previously stated many of today's imported electrical parts are worse than useless.

As for quality of the parts, the first one was purchased from Dennis Carpenter, not sure where it was made. The second was from New Holland, with CNH box, but looked just like the first one. $26.00 from New Holland. $20 from Carpenter. If I have to go buy a third, I guess I'll try solid state.
I'm 100% sure the BATT side of the cutout is connected to the Battery lead.

Thanks guys.
Brian

take the cover off of the cut-out and manually trigger it "OFF" after running to check for sure. Make sure you have excellent grounds in the system, especially where the cut-out mounts.

If anyone knows a source for a solid-state 9N cutout, please let me know.
Thanks! Brian

There are some new cutouts with the cover on backward.This is easy to check on the bench with a 6 v battery or an ohm meter.

If the cutout cover is removable, check to see that the cutout contacts are not welded together.
If not, the cutout return spring may be adjusted a bit weak so normal battery voltage keeps it closed. Increase the spring tension just a bit and see if the cutout will open when you stop the engine.
If the cutout spring is set too weak, the cutout will not open against normal battery voltage.

If the cutout spring is set too strong, it will take very high rpm to close it if it will close at all.
If you error, try to error on the side of the spring being too strong.
I would rather have to rev the engine a bit to get the cutout closed, instead of having it stay closed, discharging your battery and over heating / burning the generator.
Adjusting mechanical cutouts / regulators is about a lost art.

an electronic cutout is availble for the 36 ford car.

A diode cutout has a .7 volt drop.This produces heat that will short the diode.The generator will have to produce 8 volts.This happens to be the point where armatures heat and throw solder.Do the bench test on the cutouts to make sure they they are wired right.A 6 volt spring top battery used in flash lites will supply power to make the tests.

THANKS A LOT, Guys!

OK, I've been away a few days, but got back to this problem. I installed a new cutout, but am still puzzled by the cutout staying closed each time the motor is stopped.
Now I am running without the cutout cover so I can watch the contacts...
Starting with the gap open, it stays open until the motor is revved, then the generator is putting out about 6.8V, which is more than the battery (6.38V), and enough to make the relay close. Fine so far, ammeter on the dash shows +2 or 3 amps, OK. Every time i turn off the key, the contacts stay closed, and the ammeter goes negative, a few amps, which I think is battery current moving through the generator to ground. My assumption is that because the battery current moves through the contact, to the generator terminal of the cutout, one of the coils (I think it is the smaller inner coil) stays energized since it is grounded through the cutout mount. Consequently, current can continue to the generator and to ground there also.
I think I can fix this by moving the wire that connects the BAT terminal of the cutout FROM the lower junction post TO the left upper junction post. This will essentially put the key switch into the generator circuit, so when the key switch is off/open, both the ignition circuit and the generator circuit will be broken. It really doesn't seem right, because when the tractor runs, I'll have charging current moving through the key switch wires. Not as designed.
Two questions -
First, why is ther a fine wire coil on the cutout relay AND a large wire coil? Is one a sensing coil and one a holding coil??
Second, What is supposed to open the contacts when the generator stops moving, in other words, why does my battery current "replace" the generator current?

Thanks for all the help - Brian.

The small fine coil is the voltage sensing coil (shunt coil) and sees generator voltage & when high enough, it closes contacts to connect gen to battery. The heavy wire (series) coil carries the generator current to the battery and the magnetic field created by that current aids the shunt coil in holding the contacts closed, BUT when generator slows or stops to the point that it is no longer supplying current to the battery, then the battery is supplying current to the generator (discharging the battery). Note the reverse direction of the current flow. This reverse current in the series coil also produces a reverse magnetic field, which now is in opposition to the shunt coil and at some point should reach a magnitude which cancels the shunt coils mag field and now this zero mag field releases the contacts, thus disconnecting the generator from the battery. Next time it hangs like that, let us give a boost to that reverse current, just for educational purposes. Momentarily (perhaps a half to one second) short the gen to cut out wire to chassis & see if cut out opens.

Thanks JMOR for the fine and thorough explanation.
I will try the short "test" tonight or this weekend, and let you know what happens.
Brian

Well, I tried again, after turning off the tractor, the contact was stuck in the closed posiiton. I jumpered the GEN side of the cutout to ground, and she stayed closed. No luck there. I plan on buying another (the third) cutout, and seeing if that takes care of it.
Brian

(quoted from post at 11:48:35 03/08/10) Well, I tried again, after turning off the tractor, the contact was stuck in the closed posiiton. I jumpered the GEN side of the cutout to ground, and she stayed closed. No luck there. I plan on buying another (the third) cutout, and seeing if that takes care of it.
Brian

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f that didn't make it release, I would also declare it dead. Bob, I believe suggested a solid state cut out replacement (can purchase or build you own) and these are simple, cheap, reliable. 36 always chimes in that these make the generator run 0.7 volt higher than a good switch type cut out, but I contend that 0.7 volt is insignificant in that the battery itself will run around voltage wise more than that & further more an extra 0.7 volt will result in only a 10% increase in field current and these generators are well known to keep 8 volt batteries charged, and that is a 33% increase, so I say not to worry.
Here are links to SS cut out construction:
https://photos.yesterdaystractors.com/gallery/pieces/v5567.jpg

https://photos.yesterdaystractors.com/gallery/pieces/v764.jpg

https://photos.yesterdaystractors.com/gallery/pieces/v762.jpg

Thank you JMOR for your continued interest. I ordered a solid state cutout from Dennis Carpenter yesterday, $69.50 plus shipping. Hope that is the end of it. I will take a look at the links you provided, just curious how difficult it would be to make.
Brian

(quoted from post at 10:48:09 03/09/10) Thank you JMOR for your continued interest. I ordered a solid state cutout from Dennis Carpenter yesterday, $69.50 plus shipping. Hope that is the end of it. I will take a look at the links you provided, just curious how difficult it would be to make.
Brian

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Brian, the $69.50 9N-10505-VR isn't just a soild state cut out.......according to the manufacturer, it is a field control voltage regulator. Be sure you read & follow the installation instructions exactly, as it has delicate electronics inside, well beyond a simple diode. I would be very interested in hearing from you on how it works when you install it. If you would, jot down my e-mail address & let me hear from you. E-mail addr is showing in Modern View. Thanks.