Reversed battery polarity on 8N

[JC-jetro]

shouldn't be odd if you do electronics for a living.

you likely closed the cutout, which polerized the genny..

no need to read the reg to polerize an a circuit system.. just jump bat to armature and go.

easy to tell what circuit type if you don't know by looking at the vreg field control, since it connects the field coil to ground via a vibrating contact.. has a bias resistor from fld to grns onthe bottom of the reg too.

soundguy

soundguy

Soundguy,

You are indeed a learning/teaching smorgasbord. You need to start charging for it

JC,

[Soundguy]

naa.. these old tractor electrical systems are just too simple.. about 3' of wire.. and a few switches, couple balls of copper and other assorted bits...

soundguy

[kleake]

shouldn't be odd if you do electronics for a living.

you likely closed the cutout, which polerized the genny..

no need to read the reg to polerize an a circuit system.. just jump bat to armature and go.

easy to tell what circuit type if you don't know by looking at the vreg field control, since it connects the field coil to ground via a vibrating contact.. has a bias resistor from fld to grns onthe bottom of the reg too.

soundguy

soundguy

Well, I was meaning to say it seems odd to most people, and a little to me because I do electronics as in the internals of monitors, power supply's, and just general things, but I haven't messed much in the old car/truck/tractor world with generators.

I tried to jump the armature to the bat, but I couldn't read the terminals on the regulator, and I couldn't get any kind of spark or reaction on the generator no matter what I jumped. Could have been too much insulation on the terminals from age and corrosion or who knows. I tried for about a half hour with no luck before pulling the top off the regulator.

Now if I can figure out why she only hits on 2 cylinders when cold until warmed up for about 5 minutes I'll be doing good.

[Soundguy]

That's why i said to forget the regulator and trying to read it.. do the polerization from bat to arm at the generator.. Easy to determine which post is the armature...

One big post on back with an insulated washer.

2 small posts on the barrell, one common to the barrell, one with a phenolic washer.

non insulated post is obviously ground.

of the small and large insulated posts, armature will the the larger of the 2.. leaving.. field as the small insulated post.

jumping from armature on the back of the genny, to battery hot, is electrically the same as doing it at the genny...

soundguy

Well, I was meaning to say it seems odd to most people, and a little to me because I do electronics as in the internals of monitors, power supply's, and just general things, but I haven't messed much in the old car/truck/tractor world with generators.

I tried to jump the armature to the bat, but I couldn't read the terminals on the regulator, and I couldn't get any kind of spark or reaction on the generator no matter what I jumped. Could have been too much insulation on the terminals from age and corrosion or who knows. I tried for about a half hour with no luck before pulling the top off the regulator.

Now if I can figure out why she only hits on 2 cylinders when cold until warmed up for about 5 minutes I'll be doing good.

[stapleford]

Word of wisdom
It is possible to reverse charge a battery
Happend on my Brother in laws car a ford fiesta fuel injected xr2i
he couldnt understand why the new battery kept sparking when he tried to connnect it and all the lights came on

As control systems sparky and ex auto electric and mech fitter,
I checked it out for him and same thing happened. Took all the fuses out as thought there was a short and pulled the alt plug as well
Only when I checked the battery voltage did i twig what was happening
Battery was reverse charged

Contacted the garage that supplied it to him, but they wouldnt believe it was possible
I believe it happend thus. BIL buys battery, fits but faulty heated window relay flattens battery completely, takes back and they charge it using high current starter/ charger connected wrong giving him it back reverese charged
Damage was "just" fuel injecton parts and electronic ignition.
ECU radio and Alternator were fine
so cost him about 50 quid
Amazingly the battery recharged correctly once drained flat

Note that reverse charging can only happen if battery is totaly discharged and charger conncted in reverse has a very high output

Must say i have never checked polarity with a meter before connecting but I do now!!

[J_J]

Most good chargers will warn you with a buzzer if connected wrong. And no, I have never seen or heard of a battery reversed charged.

[RickB]

Most good chargers will warn you with a buzzer if connected wrong. And no, I have never seen or heard of a battery reversed charged.

I have. It can and does happen once in a while.

[stapleford]

Most good chargers will warn you with a buzzer if connected wrong. And no, I have never seen or heard of a battery reversed charged.

As i ssaid, it can only happen if the battery is completey discharged so you wont get a warning. However, doemstic chargers wont normally have enough current to start the reverse charge process

[david todd]

I did same recently on my 8N. Started fine, I saw ammeter spark and peg all the way to the right. Shut off tractor and took battery cables off. Have not touched since. System is 12v with alternator. Should I just put battery back in and hook up correctly (positive to starter/solenoid and negative to frame) and see what happens or are there some tests I can perform before hooking battery back up - to keep damage to a minimum. I'm a newbie so be kind.

[Soundguy]

at this point.. hook it up and test it... most likely the alternator is shot...