Anyone Running A Mechanical Voltage Regulator 67 Dart 273 2bbl

[Dana67Dart]

I have a question for anyone running a Mechanical Voltage regulator (Alternator).

I bought a used mechanical VR for way less than they go for NOS. The internals look amazing, contacts not burnt, nothing corroded inside, in fact, except for the cork gasket the insides look brand new (OEM new not recently replaced new) I assume it has never been tampered with, no signs that the cover had ever been off.

Question...

How much fluctuation should the ammeter show at idle? with my aftermarket electronic VR the ammeter is steady at idle but with the mechanical it fluctuates, not a lot, but enough that I was concerned to leave it in place. Charging voltage at the battery was good, a tad higher then the electronic VR but nothing that concerned me.

Thanks

 

[RustyRatRod]

Since it's basically an "off on" switch, some fluctuation is normal.

 

[Mattax]

As far as I can tell, the solid state regulators do the same thing, but perhaps react faster.

I think Chrysler's description from 1959 best desribes the cause of the meter fluctuations at idle.
The available alternator power finds the easiest and shortest path to the alternator. So it goes to the ignition and brakes lights first, then what remains is available for recharging the battery.
At idle speed, it doesn't take much load to cause the voltage to drop and then there are two power sources with the same voltage. We see the battery discharge as soon as its voltage and the alternator's are equal. The ammeter fluctuates as its just going over the line between discharging and charging.

I think the regulator's own draw, and the rotor draws are contributors. Some of the most noticible fluctuation I've seen are with revised squareback alternators. Also in hindsight, it seems my electronic reg failures have happened mostly with the squareback and revised squareback alternators. Their rotors seem to have higher power demands.

One day it would be interesting to run a points regulator with the cover off and see how quickly (or slowly) the points move between the positions.

 

[toolmanmike]

I have a mechanical on my 66 Dart. Yes there is a fluctuation that you can usually see in the gauge needle. Just a slight quiver.

 

[Dana67Dart]

Looks like I will try it again, this time I'll video both electronic and mechanical..

One day it would be interesting to run a points regulator with the cover off and see how quickly (or slowly) the points move between the positions

My guess is it is fairly rapid, but not as fast as electronic can do if it used a switching type regulator. If it applied a constantly variable voltage to the field then it would be smooth. I have an osiciliscope if I can only figure out how to use the bloody thing

 

[4spdragtop]

There are repops available with modern guts inside them. Cheap too around $20 or so.

 

[Mattax]

Looks like I will try it again, this time I'll video both electronic and mechanical..


My guess is it is fairly rapid, but not as fast as electronic can do if it used a switching type regulator. If it applied a constantly variable voltage to the field then it would be smooth. I have an osiciliscope if I can only figure out how to use the bloody thing

In the first part I was talking about visually watching the points fluttering.
Yea sure a scope on the voltage would be cool. The you could see if that syncs with the current on the ammeter. A bit more work for guys like us that haven't used a scope in bizzlion years. LOL.

 

[valiantwagonguy]

I run the mechanical regulators in both my 65 Valiant wagon and my 66 Valiant Convertible.Been running this type pretty much since I started driving Valiants in 1974. Yes, they fluctuate some at idle ,it's normal. I have had better luck with them than the aftermarket solid state things .

 

[KitCarlson]

If you have electronic ignition, modern entertainment system, phone chargers, best to use electronic regulator. The ripple leads to early failure of capacitors used in power supplies of electronic devices.

 

[toolmanmike]

There are repops available with modern guts inside them. Cheap too around $20 or so.

I tried one of those. It worked fine until I lost a good ground to the firewall. It overcharged the battery, boiled the acid out, made a mess under the hood, ate the wrinkle finish off my drivers side valve cover, and blew a bunch of light bulbs out. It was charging 17 volts. And all because of a bad ground.

 

[jos51700]

I tried one of those. It worked fine until I lost a good ground to the firewall. It overcharged the battery, boiled the acid out, made a mess under the hood, ate the wrinkle finish off my drivers side valve cover, and blew a bunch of light bulbs out. It was charging 17 volts. And all because of a bad ground.

Would that be any different with a mechanical or even a factory regulator?

 

[KitCarlson]

The early mechanical regulator works like a normally closed relay. It energizes the field from IGN signal, when voltage reaches setpoint (about 13.8 V) relay opens. Without ground, no way to complete relay coil circuit, it won't open.

 

[AJ/FormS]

One day it would be interesting to run a points regulator with the cover off and see how quickly (or slowly) the points move between the positions.

Back in about 69, I did just that on my 57 Chevy; it's amazing. tiny sparks flying around,yet the points seem to just quiver, moving to fast for the eye to follow.

sorta like points in a distributor machine.

 

[Mattax]

Back in about 69, I did just that on my 57 Chevy; it's amazing. tiny sparks flying around, sorta like points in a distributor machine.

Do you recall if that had current regulation as well as voltage regulation?

 

[KitCarlson]

Only if a generator.

 

[Mattax]

Only if a generator.

That makes sense. Which should be after '57 unless retrofitted.

 

[KitCarlson]

In the first part I was talking about visually watching the points fluttering.
Yea sure a scope on the voltage would be cool. The you could see if that syncs with the current on the ammeter. A bit more work for guys like us that haven't used a scope in bizzlion years. LOL.

There is a delicate balance of relay frequency vs ripple. Too fast, contacts fail to break fully, and sizzle with erosion. Slowing down rate, done by increasing ripple, voltage difference (hysteresis) between "ON" and "OFF". Electronic switch, a transistor is much faster and cleaner switching. Immune to vibration, spider nests, mechanical wear, point erosion, spring weakening...

The field current is what controls magnetic flux of N-S-N-S.... rotating, past stator coils for generation. The field is a large inductor, it stores current, regulation action increases and decreases as a sawtooth ramp, smooth, small change compared to magnitude. It is difficult to see with electronic regulator, need to expand view.

 

[Mattax]

Slowing down rate, done by increasing ripple, voltage difference (hysteresis) between "ON" and "OFF".

Very interesting that regulator created ripple is controlled by the gap settings.

I tried one of those. It worked fine until I lost a good ground to the firewall. ...t. It was charging 17 volts. And all because of a bad ground.

Would that be any different with a mechanical or even a factory regulator?

The early mechanical regulator works like a normally closed relay. It energizes the field from IGN signal, when voltage reaches setpoint (about 13.8 V) relay opens. Without ground, no way to complete relay coil circuit, it won't open.

That would be the same issue with a transistorized version of the mechanical regulator. It still compares voltage to ground, and if there's no ground, voltage appears as zero, so maximum current is let through full time.

But with the '70 up regulators, the field circuit uses the same ground as the regulator. So completely losing regulator ground means no current through the rotor.

Never thought about that before.

 

[RedFish]

But with the '70 up regulators, the field circuit uses the same ground as the regulator. So completely losing regulator ground means no current through the rotor.
Never thought about that before.

That is called isolated field. We often see members upgrade to the higher output isolated field alternator then simply chassis ground the other field terminal rather than complete the upgrade. Makes no sense to me.
I upgraded my 67 to isolated field system with used parts and about 8 feet of new blue wire to complete the upgrade. Never new there was a issue with that solid state regulator. No indication shown in OEM amp gauge needle. When I changed it to a volts gauge that needle vibrated like crazy. New regulator cured it.

 

[KitCarlson]

Very interesting that regulator created ripple is controlled by the gap settings.

Not exactly, it is "dead band" voltage. Similar issue with electronic. The dead band is voltage range around setpoint, where switching does not occur. An example is off at 13.9V, on at 13.7V, a peak ripple of 0.2V. If dead band is only 0.002V, switching too fast to fully go on and off, heating transistor, or points. The dead band is adjusted electronically by adding bias to setpoint, controlled by switch state. Ever hear of Schimitt trigger gates?

 

[Mattax]

Not exactly, it is "dead band" voltage. Similar issue with electronic. The dead band is voltage range around setpoint, where switching does not occur. An example is off at 13.9V, on at 13.7V, a peak ripple of 0.2V. If dead band is only 0.002V, switching too fast to fully go on and off, heating transistor, or points.

I follow that.
Wouldn't that be controlled by the gaps between the upper and lower points, for a given coil and spring?

The dead band is adjusted electronically by adding bias to setpoint, controlled by switch state. Ever hear of Schimitt trigger gates?

No I haven't.

 

[Mattax]

That is called isolated field. We often see members upgrade to the higher output isolated field alternator then simply chassis ground the other field terminal rather than complete the upgrade. Makes no sense to me.
I upgraded my 67 to isolated field system with used parts and about 8 feet of new blue wire to complete the upgrade. Never new there was a issue with that solid state regulator. No indication shown in OEM amp gauge needle. When I changed it to a volts gauge that needle vibrated like crazy. New regulator cured it.

That may have been one of the reasons volt meters weren't included in cars until the era of solid state regulators. Its distracting and looks like something is wrong.

In another thread Kit explained the reason Chrysler went to the ground controlling regulators and isolated field alternators.
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.

 

[Dana67Dart]

But with the '70 up regulators, the field circuit uses the same ground as the regulator. So completely losing regulator ground means no current through the rotor.

Never thought about that before.

Almost like a safety feature! That is a cool ah ha moment... love those!

 

[toolmanmike]

The ground problem I had was simply loose screw holes and painted mounting tabs. The regulator screws to the firewall with sheet metal screws. After a few R&R's the home made threads in the sheet metal strip out and you get a poor ground. The right screw had backed itself off a couple turns and the regulator was loose.

 

[jos51700]

That is called isolated field. We often see members upgrade to the higher output isolated field alternator then simply chassis ground the other field terminal rather than complete the upgrade. Makes no sense to me.
I upgraded my 67 to isolated field system with used parts and about 8 feet of new blue wire to complete the upgrade. Never new there was a issue with that solid state regulator. No indication shown in OEM amp gauge needle. When I changed it to a volts gauge that needle vibrated like crazy. New regulator cured it.

What's the right way?

It's been years but I wouldn't be surprised if I screwed this up.