Solid state regulator conversion confusion!

[smokinnjokin]

Gentlemen,
You may have followed my painful HEI conversion project last year, that against all odds I never got to work properly. Circling back around, the only thing that I didn't rule out was that I still had a solid-state regulator that was putting out around 14.7 volts. So I'm working on converting it to solid-state with a 70's alternator. Only thing is... It looks like I already have a 70's style alternator... hooked to an old school regulator. This shouldn't work, right? Looking at wiring diagrams for '67 satellite, they only show 1 field wire and I have 2. How do I add the solid-state regulator to my current setup - I have seen the conversion wiring diagram on the forum, my question is where the heck is my field wire on the right (the big one with black tape) going? Is that a chassis ground??

 

[smokinnjokin]

Just checked, both wires have continuity with the alternator case with the car shut off. So the green wire and that side of the regulator is currently running to ground via the alternator case. Does that mean the alternator is running full field all the time?

 

[RustyRatRod]

Pull the black wire off the field of the alternator and check continuity to ground. With the battery disconnected, of course. One of those field wires to ground and one to the regulator. That's how it goes.

Del can help more. @67Dart273

 

[smokinnjokin]

I guess the real confusion is that the new alternator I ordered (against a mid-70's Mopar with matched solid-state regulator) looks identical to the one that is on the car now. The two field wires are not labeled + and _. Which is which?

 

[67Dart273]

In this case I can tell just by looking. The terminal to which the green is connected HAS NO INSULATOR.

This stuff is dead nuts simple, but complicated by problems such as this, here is the deal:

69/ earlier alternator have one brush grounded. The old style regulator has ground, switched 12V to it, and the green wire to the only field.

70/ later are SUPPOSED to be fully insulated from ground, with two brush/ field terminals. The VR gets ground, 12V and the green wire to either field. The remaining alternator field is also connnected to switched 12V

There is a number of reasons why late model alternators INCORRECTLY get one brush grounded. This includes...........

Sloppy rebuilders who leave out insulator hardware
Sloppy rebuilders who "convert" early (grounded) ones to isolated ones, then incorrectly do the conversion and leave it grounded anyway..........

and so on............

 

[67Dart273]

Wait a minute, I may have eff'd up. Did you check continuity with BOTH field wires disconnected? The black wire to the right may be a grounding wire for the early regulator................

 

[RustyRatRod]

Wait a minute, I may have eff'd up. Did you check continuity with BOTH field wires disconnected? The black wire to the right may be a grounding wire for the early regulator................

He said above the black wire on the right had continuity to case ground.....if I am reading it correctly.

 

[smokinnjokin]

Correct, black wire grounds case to the chassis. What I don't get is what is different about the old alternator (left picture) and new 70's model. They appear identical.

 

[pishta]

the only difference between a dual field squareback and roundback is the serviceable pressed in diodes of the squareback. all other things being equal. There is no + and - on the distributor leads. either will work, (one closest to lug is labeled as + in FSM) they both end up at the 2 position plug of the electronic regulator with one tapped off to the ignition wire. Make sure you have a good ground (star washer) from the regulator case to the firewall. any dual field can work as a single if one of the fields is grounded to the case and the other goes to your old mechanical regulator, as I have been told.

 

[Dana67Dart]

As 67dart273 mentioned, the alts can look the same but be internally wired differently.

IMHO best bet is to disconnect both field wires and then check each field terminal (not the wire) to ground, and report back

 

[67Dart273]

Correct, black wire grounds case to the chassis. What I don't get is what is different about the old alternator (left picture) and new 70's model. They appear identical.

Please re-read my post. You must remove BOTH field wires from the alternator and check continuity from the field to ground. It should be OPEN. If this is so all you need do is hook up the new regulator.

One field terminal goes to VR via green

VR must be grounded
VR gets switched 12V
VR has the green connected to one field

Other alternator field terminal goes to switched 12V "ignition run"

The old system, the VR sent power TO the alternator field. More power to the field= more output
The new system controls the "ground" via the green wire. One field terminal gets 12V instead of ground (old) and the VR controls "the amount of ground" so to speak

 

[moparmat2000]

Also going to add to the topic, that this red wire that's kinked like that by the connector is a no no as well. All the wires should have a smooth arc or curvature and should not be pulled or kinked like this. Not sure what this additional 12V lead is for, but at the very least position it so the wire isnt kinked like that. A wire positioned like that will give you problems sooner than later.

Normally the 70s dual field alternators have a green jumper wire from the first green field connection jumping to the second field connection, and case ground to the block. Now as far as how the VR is wired up and if the alternator was rebuilt correctly to allow this wire setup from the VR, that's detective work you will have to do. See pix below. Fixed for ya!!!

 

[Dana67Dart]

Normally the 70s dual field alternators have a green jumper wire from the first green field connection jumping to the second field connection

Don't see how that could work. You would be applying the same potential to both ends of the field coil.

Totally agree about the kinked wire.

 

[smokinnjokin]

Please re-read my post. You must remove BOTH field wires from the alternator and check continuity from the field to ground. It should be OPEN. If this is so all you need do is hook up the new regulator.

One field terminal goes to VR via green

VR must be grounded
VR gets switched 12V
VR has the green connected to one field

Other alternator field terminal goes to switched 12V "ignition run"

The old system, the VR sent power TO the alternator field. More power to the field= more output
The new system controls the "ground" via the green wire. One field terminal gets 12V instead of ground (old) and the VR controls "the amount of ground" so to speak

On the old alternator, if I unhook both ground and field wire, BOTH connectors have continuity to the alternator case. On the new alternator, neither spade connector has continuity to the case.

Is there supposed to be an insulating washer under both of the screws on the field wires on the old alternator? The new one has them on both. Currently, the left one (green field wire) has the insulating washer but is grounding to the case anyway, and the right one (black wire) has no insulating washer and is also grounding to the case. Should they be switched, or are both supposed to have the insulating washers?

The kinked wire is an additional 10gua path to the starter relay stud. I straightened it out.

 

[67Dart273]

Is there supposed to be an insulating washer under both of the screws on the field wires on the old alternator? The new one has them on both. .

YES. All isolated/ dual terminal alternators WHEN NEW are supposed to be isolated from ground. That is why they are called "isolated field."

The PROBLEM is that some rebuilders and some owners remove the insulators to convert them back to "early" alternators. This is find IF THE WIRE TERMINAL is removed so you cannot hook a wire onto the grounded terminal. If you accidently hook the green VR wire to the grounded terminal, you will ruin the VR.

If you can find hardware (brush set) to fit the one you have, it will work fine with a new style regulator.

 

[Dana67Dart]

Some of the grounding you are seeing is the field coil with one side grounded

 

[Mattax]

On the old alternator, if I unhook both ground and field wire, BOTH connectors have continuity to the alternator case. On the new alternator, neither spade connector has continuity to the case.

Pay close attention to what 67Dart273 has posted.
I'll try to clarify the terms that will make the discussion clearer.
Field is short for "electromagnetic field" The physical part that creates this field is the rotor. The rotor gets electricity through carbon brushes that rub against slip rings on the rotor.

The pre-1970 'roundback' alternators have one brush grounded to the case and the other brush has terminal and is in an insulated holder.

The only way to isolate the rotor from ground is to remove the grounded brush from the cast holder.

The 1970-71 'roundback' alternators had both brushes insulated from the housing. Each brush has a terminal. So these isolated field alternators have two field terminals.

In 1972 model year, a new 'squareback' alternator was introduced. It is also an isolated field alternator with two field terminals.
In the photos you posted I see a squareback.

Is there supposed to be an insulating washer under both of the screws on the field wires on the old alternator? The new one has them on both. Currently, the left one (green field wire) has the insulating washer but is grounding to the case anyway, and the right one (black wire) has no insulating washer and is also grounding to the case. Should they be switched, or are both supposed to have the insulating washers?

I don't know what old and new refer to, but terminals used with insulated brushes do get insulated washers. Exception being if one is purposely reworked to be grounded so as to work with the pre-70 type of regulator and wiring.

The kinked wire is an additional 10gua path to the starter relay stud. I straightened it out.

There really shouldn't be a direct connection, but if there is, it should be protected (eg fusible link) and there should be a dash mounted voltmeter.

Insulating washers should be available locally, but if not this place has 'em.
Premium Quality Alternators, Starters, Parts, Rebuild Kits
Premium Quality Alternators, Starters, Parts, Rebuild Kits

 

[smokinnjokin]

the only difference between a dual field squareback and roundback is the serviceable pressed in diodes of the squareback. all other things being equal. There is no + and - on the distributor leads. either will work, (one closest to lug is labeled as + in FSM) they both end up at the 2 position plug of the electronic regulator with one tapped off to the ignition wire. Make sure you have a good ground (star washer) from the regulator case to the firewall. any dual field can work as a single if one of the fields is grounded to the case and the other goes to your old mechanical regulator, as I have been told.
View attachment 1715584559

I wired the new alternator up exactly as described and it is working well. Tomorrow I will do the necessary wire splicing for the new VR. Thank you for the information, all.

And yes, that red 10g wire that has been the topic of discussion is fused.

 

[smokinnjokin]

Pay close attention to what 67Dart273 has posted.
I'll try to clarify the terms that will make the discussion clearer.
Field is short for "electromagnetic field" The physical part that creates this is the rotor. The rotor gets electricity through carbon brushes the rub against slip rings on the rotor.

The pre-1970 'roundback' alternators have one brush grounded to the case and the other with a field terminal is in an insulated holder.
View attachment 1715584732
The only way to isolate the rotor from ground is to remove the grounded brush from the cast holder.
View attachment 1715584733

View attachment 1715584734

The 1970-71 'roundback' alternators had both brushes insulated from the housing. Each brush has a terminal. So these isolated field alternators have two field terminals.
View attachment 1715584731

In 1972 model year, a new 'squareback' alternator was introduced. It is also an isolated field alternator with two field terminals.
In the photos you posted I see a squareback.



I don't know what old and new refer to, but terminals used with insulated brushes do get insulated washers. Exception being if one is purposely reworked to be grounded so as to work with the pre-70 type of regulator and wiring.


There really shouldn't be a direct connection, but if there is, it should be protected (eg fusible link) and there should be a dash mounted voltmeter.

Insulating washers should be available locally, but if not this place has 'em.
Premium Quality Alternators, Starters, Parts, Rebuild Kits
Premium Quality Alternators, Starters, Parts, Rebuild Kits

This explained exactly what was going on, thank you. Old alternator was hooked up incorrectly, it had a lot of bearing play anyway so I went ahead and installed the new one properly. Problem solved.

 

[67Dart273]

Hey like cool 'n stuff!!!

 

[pishta]

Is this a sticky somewhere? Seems this comes up once a month....and rebuilding a functional but worn out alternator is about as easy as putting new wheels on a skateboard if the diode packs are still good.
Split the case, install 2 new ABEC 1 bearings and 2 new $1.39 carbon brushes. Check the slip rings for uniform gaps in the mica, put it back together and go.

 

[coalman]

I have a question, on the Pre-1970 Alternator mine looks nothing like the picture of the backside. I have a screw hole for the FLD-/ Ground to case, no wire, and no Chassis Ground either. What affect would this have, and wouldn't the alternator be grounded through Alternator Engine mount? Thanks

 

[67Dart273]

From your description this sounds typical. The older "grounded field" units had no evident terminal for the second brush They were a metal piece holding the brush, inserted into the case and held by a screw. And yes, all the small frame alternators of which we speak are grounded by the mount.

 

[coalman]

From your description this sounds typical. The older "grounded field" units had no evident terminal for the second brush They were a metal piece holding the brush, inserted into the case and held by a screw. And yes, all the small frame alternators of which we speak are grounded by the mount.

Thanks for reply...

 

[Mattax]

Here's a nice example of a standard pre-1970 alternator from Plum crazy tech info

Next is an example of a standard 1970-71 roundback from this moparts thread.

The sloppy paint colors were for factory identification.

Here's a pic Scott Smith Harms took of probably an original 70-71 installed.