Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
b body charging system.. #2822925
09/20/20 02:13 PM
09/20/20 02:13 PM
Joined: Apr 2020
Posts: 14
canada
C
cwilson66 Offline OP
member
cwilson66  Offline OP
member
C

Joined: Apr 2020
Posts: 14
canada
Hey guys lots of into floating around about the charging systems but i have a couple questions-first its a 66 charger just put it back together after 10 years of sitting in the shop with no engine. anyhow
it had the old style regulator with the dual field square back alt.. it worked 10 years ago but after firing up the new engine it wasnt charging i had the alt tested -ok so i replaced the old regulator with a "new" style one. rewired it and it was charging at 13.5 at idle-perfect

200 km trip and i started to smell battery.. sure enough its charging at 15.5v at idle now and was cooking the battery.
so while idling if i unplug the blue field wire from the alt it stops charging, the green wire seems to have no effect weather its plugged in or not.

now with both blue and green field wires unplugged engine off, if i test for continuity between bat neg and either field terminal on the alt i have continuity, is that normal? also unplugged the regulator and i dont have any continuity between regular posts if that means anything.

some help would be great
thanks

Re: b body charging system.. [Re: cwilson66] #2822951
09/20/20 03:38 PM
09/20/20 03:38 PM
Joined: May 2019
Posts: 6,175
nowhere
S
Sniper Offline
master
Sniper  Offline
master
S

Joined: May 2019
Posts: 6,175
nowhere

If I understand your setup, you are running the newer dual field terminal charging system.

If that is so then neither terminal should be shorted to ground. Once side, blue wire, should be a switched 12v and the other side, green wire, is controlled by the voltage regulator.

Sounds like the alternator has a short in it and is full fielding, which would be consistent with the 15.5v you are seeing.

Re: b body charging system.. [Re: cwilson66] #2823100
09/20/20 10:44 PM
09/20/20 10:44 PM
Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx Offline
super stock
72roadrunnergtx  Offline
super stock

Joined: Oct 2008
Posts: 765
Shoreline, Washington
Sounds like you were running the square back alt on a pre-’70 application. Likely one field terminal is intentionally grounded by the removal of a brush assembly insulating washer, substituting a metal washer. As mentioned, on a later isolated field system, there can be no continuity from either field brush/terminal to the case. Check the washer under the mounting screw head that the green wire currently connected to, make sure it’s an insolating washer.


1972 Road Runner GTX 440 6bbl 5-speed
[img]http://72rrgtx.com/carpics/bucket/DSC06730r-1.jpg[/img]
Re: b body charging system.. [Re: cwilson66] #2823191
09/21/20 09:58 AM
09/21/20 09:58 AM
Joined: Jan 2003
Posts: 10,666
North Dakota
6PakBee Offline
I Live Here
6PakBee  Offline
I Live Here

Joined: Jan 2003
Posts: 10,666
North Dakota
Originally Posted by cwilson66

it had the old style regulator with the dual field square back alt.. it worked 10 years ago but after firing up the new engine it wasnt charging i had the alt tested -ok so i replaced the old regulator with a "new" style one. rewired it and it was charging at 13.5 at idle-perfect


It sounds like when you rewired it you missed something As a minimum you have to run an additional wire from the alternator to the voltage regulator when you change from the grounded field to the ungrounded field alternator.

Charging Circuits


"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
Re: b body charging system.. [Re: 6PakBee] #2823237
09/21/20 12:21 PM
09/21/20 12:21 PM
Joined: Apr 2020
Posts: 14
canada
C
cwilson66 Offline OP
member
cwilson66  Offline OP
member
C

Joined: Apr 2020
Posts: 14
canada
its wired just like the 1970 and up diagram,

Re: b body charging system.. [Re: 72roadrunnergtx] #2823238
09/21/20 12:22 PM
09/21/20 12:22 PM
Joined: Apr 2020
Posts: 14
canada
C
cwilson66 Offline OP
member
cwilson66  Offline OP
member
C

Joined: Apr 2020
Posts: 14
canada
sounds like you may be right... i can take it apart and have a look but still strange how theres continuity between either field terminal and the case?

Re: b body charging system.. [Re: cwilson66] #2823244
09/21/20 12:32 PM
09/21/20 12:32 PM
Joined: Jan 2003
Posts: 10,666
North Dakota
6PakBee Offline
I Live Here
6PakBee  Offline
I Live Here

Joined: Jan 2003
Posts: 10,666
North Dakota
Originally Posted by cwilson66
sounds like you may be right... i can take it apart and have a look but still strange how theres continuity between either field terminal and the case?


Not strange at all. If one terminal is grounded, there is direct continuity. The other terminal is grounded through the field winding to the other field terminal which is grounded, indirect continuity if you will.


"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
Re: b body charging system.. [Re: cwilson66] #2823247
09/21/20 12:35 PM
09/21/20 12:35 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
Circle Track
Happy Birthday RapidRobert  Offline
Circle Track

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Quote
it had the old style regulator with the dual field square back alt.. it worked 10 years ago.
so while idling if i unplug the blue field wire from the alt it stops charging, the green wire seems to have no effect weather its plugged in or not.
now with both blue and green field wires unplugged engine off, if i test for continuity between bat neg and either field terminal on the alt i have continuity, is that normal?
I'm missing something cuz the 2 field terminal alt would not work with the old style "box" reg but you said it was charging in the 13's way back so I missed something there. DO you have the flat one or the box? if either of the male field terminals on the alt are grounded then there is an alt issue, as said start by checking the brushes, grab your vom. EDIT I see that you have the later system (flat reg), something inside the alt is grounded with there being continuity from one or both alt field terminals to the batt neg

Last edited by RapidRobert; 09/21/20 12:40 PM.

live every 24 hour block of time like it's your last day on earth
Re: b body charging system.. [Re: 6PakBee] #2823254
09/21/20 12:46 PM
09/21/20 12:46 PM
Joined: Sep 2003
Posts: 19,239
north of coder
moparx Offline
"Butt Crack Bob"
moparx  Offline
"Butt Crack Bob"

Joined: Sep 2003
Posts: 19,239
north of coder
Originally Posted by 6PakBee
Originally Posted by cwilson66
sounds like you may be right... i can take it apart and have a look but still strange how theres continuity between either field terminal and the case?


Not strange at all. If one terminal is grounded, there is direct continuity. The other terminal is grounded through the field winding to the other field terminal which is grounded, indirect continuity if you will.



i had a cracked brush holder do that to me one time. when i discovered it and took the holder out, it broke into pieces.
beer

Re: b body charging system.. [Re: moparx] #2823261
09/21/20 12:54 PM
09/21/20 12:54 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
Circle Track
Happy Birthday RapidRobert  Offline
Circle Track

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Now if the green wire is normally grounded thru the flat reg case with it not running (I dont know) then the field terminals being grounded at that point in time would be normal. so the full fielding is somewhere else. with the alt checking out OK at the parts house (not always 100% but close) I think the reg is full fielding.


live every 24 hour block of time like it's your last day on earth
Re: b body charging system.. [Re: cwilson66] #2823263
09/21/20 12:55 PM
09/21/20 12:55 PM
Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
IMGTX Offline
I Live Here
IMGTX  Offline
I Live Here

Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
Controlling the field strength controls the output of the alternator.
The old 1 wire alternator's used a variable signal through the blue (+) wire to control the field strength They were direct grounded.
The newer 2 wire alternators use a continuous power through the blue wire and control the field by varying the ground through the green wire.

If it is over charging you either have a grounded field wire inside the alternator, a short to ground in the green wire or the VR (Voltage Regulator) bit the big one.

Disconnect the field wires from the alternator and the regulator.
Check for a ground from the green wire to the engine/negative terminal. If it is disconnected at both ends and has a ground then there is a short.
Check for grounds from the field ternimals to the alternator housing WITH THE WIRES DISCONNECTED. If there is a ground you have a shorted alternator field.

If it isn't grounded it sounds like the Voltage Regulator took a dive.

I carry extras in my glove box because the new ones are garbage.

Re: b body charging system.. [Re: RapidRobert] #2823268
09/21/20 12:59 PM
09/21/20 12:59 PM
Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx Offline
super stock
72roadrunnergtx  Offline
super stock

Joined: Oct 2008
Posts: 765
Shoreline, Washington
OP " the green wire seems to have no effect weather its plugged in or not."
This statement in the original post would eliminate anything external to the alternator brushes.


1972 Road Runner GTX 440 6bbl 5-speed
[img]http://72rrgtx.com/carpics/bucket/DSC06730r-1.jpg[/img]
Re: b body charging system.. [Re: 72roadrunnergtx] #2823277
09/21/20 01:11 PM
09/21/20 01:11 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
Circle Track
Happy Birthday RapidRobert  Offline
Circle Track

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Originally Posted by 72roadrunnergtx
OP " the green wire seems to have no effect weather its plugged in or not."
This statement in the original post would eliminate anything external to the alternator brushes.
point taken up


live every 24 hour block of time like it's your last day on earth
Re: b body charging system.. [Re: 72roadrunnergtx] #2823279
09/21/20 01:14 PM
09/21/20 01:14 PM
Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
IMGTX Offline
I Live Here
IMGTX  Offline
I Live Here

Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
Originally Posted by 72roadrunnergtx
OP " the green wire seems to have no effect weather its plugged in or not."
This statement in the original post would eliminate anything external to the alternator brushes.


I missed that one. Sounds like a bad alternator (Internally grounded field) or there is a hokey wiring setup that wasn't described but I believe him when he says it was wired correctly.

Disconnect both field wires from the alternator. If there is a connection from the terminals to the alternator case there is a short.

Re: b body charging system.. [Re: IMGTX] #2823344
09/21/20 03:50 PM
09/21/20 03:50 PM
Joined: Aug 2007
Posts: 6,089
Valencia, España
NachoRT74 Offline
master
NachoRT74  Offline
master

Joined: Aug 2007
Posts: 6,089
Valencia, España
if one of the brushes is grounded ( intentionally or accidentally ) we must say thanks God is not the one getting the blue wire, because if so, will inmediatly short out and burn the wire as soon you put the key in RUN.


With a Charger born in Chrysler assembly plant in Valencia, Venezuela
Re: b body charging system.. [Re: NachoRT74] #2823367
09/21/20 04:56 PM
09/21/20 04:56 PM
Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
IMGTX Offline
I Live Here
IMGTX  Offline
I Live Here

Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
Originally Posted by NachoRT74
if one of the brushes is grounded ( intentionally or accidentally ) we must say thanks God is not the one getting the blue wire, because if so, will inmediatly short out and burn the wire as soon you put the key in RUN.


Very Very true

It's still important to disconnect both field wires when checking for shorted fields. If you leave the blue one hooked up when checking for a shorted field you will almost always get a false positive. The blue wire also directly, or indirectly, connects to solenoids, coils and such so it will tell you there is a ground when it is just current finding its way home through another device.

My apologies if I didn't explain why.

Re: b body charging system.. [Re: IMGTX] #2823413
09/21/20 07:47 PM
09/21/20 07:47 PM
Joined: Apr 2020
Posts: 14
canada
C
cwilson66 Offline OP
member
cwilson66  Offline OP
member
C

Joined: Apr 2020
Posts: 14
canada
so just to clarify, this alt was used 10 plus years ago on the car when it had the old style regulator, after removing the alt this evening and having a better look at it the field terminal where the green wire goes has no plastic washer under the screw, the terminal where the blue wire goes does have the plastic washer.. so the field terminal with out the plastic washer is grounded to work with the pre 1970 regulator, make sence? that was my over sight, however the other field terminal with the plastic washer still has continuity to the alt case its self,

with the car running when i would go to plug the blue wire in it would spark you would hear the idle drop slightly and it would be charging ar 15 volts up to 18 off idle. i decided to try plugging the blue wire onto the other field terminal and it instantly shut the car off..

Re: b body charging system.. [Re: cwilson66] #2823437
09/21/20 08:30 PM
09/21/20 08:30 PM
Joined: Oct 2008
Posts: 765
Shoreline, Washington
72roadrunnergtx Offline
super stock
72roadrunnergtx  Offline
super stock

Joined: Oct 2008
Posts: 765
Shoreline, Washington
You were seeing continuity through the field winding to the grounded terminal from the insulated terminal. And as mentioned, connecting the blue wire to a grounded terminal normally results in a lot of burned up wiring, you’re lucky it stalled it first. Find a fiber washer for the grounded terminal screw, problem solved.

Last edited by 72roadrunnergtx; 09/21/20 09:06 PM.

1972 Road Runner GTX 440 6bbl 5-speed
[img]http://72rrgtx.com/carpics/bucket/DSC06730r-1.jpg[/img]
Re: b body charging system.. [Re: 72roadrunnergtx] #2823531
09/22/20 08:10 AM
09/22/20 08:10 AM
Joined: Jun 2014
Posts: 1,319
VA
D
dragon slayer Offline
pro stock
dragon slayer  Offline
pro stock
D

Joined: Jun 2014
Posts: 1,319
VA
May have been stated earlier; but the new style double field alternator can be used with the old style regulator. You just ground the brush with a wire or to the case by removing insulator. When you swapped to electronic regulator, you had the control feature shorted. Not sure what your battery state was, but if drained, it is possible that was dragging down voltage as the alternator was charging at full from such a low initial charge.

Then the battery finally fully charged on your trip and then over charged as you had no voltage regulation. You were at full.
So take the alternator to an auto parts store and they will test it. Chances are it is fine.
Then have the second field winding brush set back up correctly insulated. Frankly, do that before you have it tested.

Then get a new regulator. I am sure it is toast. You should not be pulling and attaching under power. You also grounded the field winding that should never touch ground.
Inspect your harness closely, put the tested alternator, and new regulator in an try it.

Re: b body charging system.. [Re: cwilson66] #2823686
09/22/20 04:06 PM
09/22/20 04:06 PM
Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
IMGTX Offline
I Live Here
IMGTX  Offline
I Live Here

Joined: Apr 2003
Posts: 12,188
Looking for a way out of Middl...
Originally Posted by cwilson66
so the field terminal with out the plastic washer is grounded to work with the pre 1970 regulator, make sence?

with the car running when i would go to plug the blue wire in it would spark you would hear the idle drop slightly and it would be charging ar 15 volts up to 18 off idle. i decided to try plugging the blue wire onto the other field terminal and it instantly shut the car off..

What you did was unknowingly ground the blue wire. The blue wire is the positive field wire which also connects to the ignition system, various solenoids and such.

The only fuse in the blue wire circuit is the fusible link. Check the fusible link for damage.

Originally Posted by cwilson66
that was my over sight, however the other field terminal with the plastic washer still has continuity to the alt case its self,


The field (Rotor winding's) inside the alternator is just a large continuous coil of wire. If either end is grounded then both ends will be grounded.

Page 1 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1