Is it possible to keep old style electronic VR with a dual field alternator?

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Joey4speed

Joey4speed

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Hi guys,
Just had all wiring harnesses replaced and restored instrument cluster put together in my 69 GTS. We weren't sure how to keep the original looking voltage regulator (which has electronic internals) on the firewall. So, my "friend" cut the triangle connector and doubled up the spade for the Ignition side of the regulator.? He thought it was working, but obviously it was not.
Using a dual field round back alternator since I'm running electronic ignition, which is hidden.

Problem is: not charging. Ammeter stays centered until eventually battery discharges. Voltmeter across the battery verifies same.
Is it possible to keep the original looking VR and use the dual field alternator? Not sure how to make the circuit work.

Im chasing my tail, reading the two different wiring diagrams, trying to figure out what the heck was changed! And of course, really trying to keep the original look. Any suggestions?
(Pics attached)
Thanks
69 style regulator (electromic).jpg


Alt.jpg
regulator and resistor.jpg
 
Wire it up back the way it was, and make a small jumper wire that goes from the 2nd field of the alternator and ground it to the case of the alternator.
 
Yes. Remove the blue wire that goes from regulator IGN to alternator field, then ground alternator field terminal it was on. Leave blue wire from ignition circuit on IGN terminal of regulator.

The old style regulator energizes the green terninal.
 
So what you are saying is to go back to a Single Field alternator? I wouldn't mind doing that at this point. Does anyone know why Chrysler memos say that you must switch to dual field when using electronic ignition?
 
I think what they are saying is by grounding one of your dual field wire terminals on your existing alt you can control it with your 1 wire field regulator. (PURE GUESS HERE... old single wire alternators used a mechanical regulator and maybe the making and braking of the field created noise that the electronic dist interpreted as a signal to fire?)
 
The old and new style alternators are very similar, it takes 2 wires for a field. The old style had one grounded at case, so when you ground the point where blue wire connected, same electrically. There are carbon brushes that feed the rotating field. There are actually insulators that are used for the new style alternators. It easily changes style.

The new style alternator, with new regulator feeds one terminal like you had wired shown above, then the green wire is switched to ground for regulator action. But as I said earlier, old style powers green wire, so no current flows and no worky when blue powers other terminal.

Just don't add ground to blue if it also connects to Ign, wires will smoke, car no start.
 
KitCarlson said:
Yes. Remove the blue wire that goes from regulator IGN to alternator field, then ground alternator field terminal it was on. Leave blue wire from ignition circuit on IGN terminal of regulator.

The old style regulator energizes the green terninal.
Click to expand...
Cleaner ac sine wave
 
Dual field alternator is really a misnomer. There is only one field coil on both. On the earlier alternators one side of the field coil is grounded at the alternator. On the 70 up alternators both sides of the field go to the regulator or power.
 
This post is related to Halifaxhops post about 2 phase ac generator. I shold have posted quote.

That does not related to mopar alternators. Mopar alternators have single field with slip rings on rotor and 3 phase on stator. The stator is 3 phase full bridge rectified for less ripple.
 
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edit: Kit already got it. They're both Y wound. So its 3 phases rectified which ever way you do it.
Flickering or pulstating Headlights

Joey4speed said:
Im chasing my tail, reading the two different wiring diagrams, trying to figure out what the heck was changed! And of course, really trying to keep the original look. Any suggestions?
(Pics attached)
Click to expand...
Don't know what diagrams you're looking at but this is definately wrong. The suggestions made are correct.
upload_2019-7-20_20-19-39.png


cosgig said:
Wire it up back the way it was, and make a small jumper wire that goes from the 2nd field of the alternator and ground it to the case of the alternator.
Click to expand...
Maybe this is hard to visualize but that's all that's needed.
A common way of grounding one terminal.
upload_2019-3-28_8-36-32-png.png


However if you want a more hidden method you can use a copper washer under the brush like I did here:
Alternator repair, a little show and tell.

Joey4speed said:
Is it possible to keep the original looking VR and use the dual field alternator? Not sure how to make the circuit work.
Click to expand...
To finish answering the wiring - Return it to original.

Lets look at how 'single field' regulator works. Key on, system power is available at the regulator. If the voltage is low, it lets current flow through with no restriction. When voltage get too high, it interupts the flow. In between is restricted flow.
upload_2019-4-13_15-33-27-png.png

The second field terminal is the ground terminal. That's all there is to it.
Field is shorthand for magnetic field. The rotor windings create a magnetic field when electricity flows through them.

Joey4speed said:
Using a dual field round back alternator since I'm running electronic ignition, which is hidden.
Click to expand...
'70 - '71 were the only years with two terminal roundbacks like the one shown above.
The instructions for adding the Chrysler electronic ignition was to use an electronic regulator. Apparently the mechanical switching was too noisy or not tight enough control for the Chrysler ECU. In any event you should be fine on that front.

Joey4speed said:
Problem is: not charging. Ammeter stays centered until eventually battery discharges. Voltmeter across the battery verifies same.
Click to expand...
Sounds like something else is miswired.
Engine off, or alternator not working, the ammeter shows the current flowing out of the battery run anything and everything except the starter.
When the alternator system is working, the ammeter shows only the current for battery charging. Once the battery is charged it shows zero.
 
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The electronic regulators were low side switched because in the early 70's NPN transistors were more reliable and cost much less than PNP, necessary for hign side switching. The old style electronic units became available in the late 80s.
 
The main and iginition circuit on '68 and '69 Barracuda will look something like this.
upload_2019-7-20_21-1-30.png


The dark blue wire ( or dark blue with stripe ) from the firewall connector carries the power when key in run position. The terminal connection at the ballast is used for a junction. A blue (or blue with trace wire) brings power to the regulator. Power for the ignition coil goes through the resistor.

If you have the original harness, then get a Packard 58 - Chrysler type open barrel terminal and crimp like this.
upload_2019-3-3_0-35-43-png.png


If you have repop harness with packard 56 terminals, then use a Packard 56. That way you're sure it fits the plastic connector.
 
KitCarlson said:
The electronic regulators were low side switched because in the early 70's NPN transistors were more reliable and cost much less than PNP, necessary for hign side switching. The old style electronic units became available in the late 80s.
Click to expand...
Thanks Kit!

For fun I was trying to figure out the basic electronic VR circuit.
Usually the master tech booklets are pretty good, but in this case Tech and the illustrator seem to have goofed.
The 1970 Alternator & Regulator (Session 269) from the Master Technician's Service Conference
There is a photo of the guts, but this is over my head. I can follow but not reverse engineer this. There's too many things they left out of the schematic.
So got this far and stopped.
upload_2019-7-14_16-20-2-png.png
 
Mattax said:
The main and iginition circuit on '68 and '69 Barracuda will look something like this.
Click to expand...
For the ECU, it could be tapped in as a splice, or added neatly at the voltage regulator terminal.
Either case it will get power when the key is in run ( and also when the key is in start). I don't know what the ECU draw is. Given a choice I'd go for 16 gage over the 18 awg for the wire to the votlage regulator.
upload_2019-7-20_21-44-3.png
 
Thanks Guys, question for Mattax,
I understand about grounding the other alternator field.
Am I loosing anything by reverting back to single field? It seems the dual field is better for the electronic ignition. Would it be best to try and hide the flat type regulator somewhere and keep the 2 fields if I cannot integrate this original looking regulator??
My friend cut out the triangle connector and thinks he put both on the spade into the top (ign) regulator. I have a good 69 Dart wiring diagram (attached), but need to UNdo the mystery splice, find out what colors and where the original triangle connector was removed, and then retrace the steps.
I have been really trying to keep the correct original look and would hate to loose it now.
Brief history...(I ordered all wiring harnesses from Laysons and had them directly shipped to my friends place, where the car was being put together, so unfortunately, I never even saw the repop harnesses from the start).
Just got the car back the day before Carlisle PA, so its all new to me also.
Thanks for your help!
69 wiring.jpg
 
cosgig said:
Wire it up back the way it was, and make a small jumper wire that goes from the 2nd field of the alternator and ground it to the case of the alternator.
Click to expand...

I don't even go to that trouble. All I do is take the field blade off of the one I want grounded, remove the insulating washers and screw it back down. Grounded.
 
RustyRatRod said:
I don't even go to that trouble. All I do is take the field blade off of the one I want grounded, remove the insulating washers and screw it back down. Grounded.
Click to expand...

That’s how old school I am I guess. I don’t even like doing it that way, I usually get the newer style VR and plug and just splice it in. But, I’ve done the pigtail many times too! This old dog is hard to train new tricks, just me I guess.
 
Cosgig,
Do you recall which wires you splice the newer style VR plug into?
Im trying to back track someone elses handiwork.
 
The basic operation of a regulator is an electrical comparator. The mechanical regulators worked the same way. The mechanical regulators were a normally closed relay, that opened field current when relay coil voltage was high enough to open contacts. The resistors, return spring set the threshold and hysteresis. Hysteresis is the dead zone of a few tenths, in the comparator action. A HVAC thermostat works in a similar fashion.

Electronic regulators work the same way, but transistors are a much cleaner switch than contacts. They are not influenced by vibration, erosion, temperature variation, insects ... a huge list of others.

With the switching, inductance of field coil stores the current, so the current builds in a ramp fashion, and also has a smooth decay. With a high resolution scope the current observation is similar to a fine hacksaw blade.

Transistors are efficient as switches, ON, or OFF, but not good, very lossy like resistor in active state, wasting electricity in excess. Today's electronics power controls are switch based, and methods improved over basic comparator, for noise reduction, power factor improvement....

The field winding generates the North and South in the interlaced end pedals. As they spin N-S-N-S, or S-N-S-N it does not matter, rotation direction, nor field polarity.
 
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Joey4speed said:
Cosgig,
Do you recall which wires you splice the newer style VR plug into?
Im trying to back track someone elses handiwork.
Click to expand...

There are 2 wires on the old VR, and the same 2 wires on the new VR, both units use the same color wires. The green wire is the existing field wire, and to add the 2nd field wire you splice it into the blue wire.
 
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