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Topic ClosedAlternator and Regulator ID and connectors

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billd View Drop Down
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Direct Link To This Post Topic: Alternator and Regulator ID and connectors
    Posted: Sep/24/2009 at 10:20pm
Going to try to make this a reference for the regulators used on AMC cars up through 1971, will add later years and more information as I get time...

Folks often ask about putting alternators from different years on their cars, what regulators to use, what about the wiring, what is the right regulator for their year car, etc. 
 
 - we'll start with the most common, or at least the most popular here, with the AMX and Javelin crowd.....

 
In 1968 model year, a change was made and the R2AM2 regulator was used. The connection was the same as the R2AM1 used in 1966 and 1967, but the tag was black and the voltage setting a bit different.
This is the R2AM2, note the 2 male and 2 female bullet connectors like the R2AM1 used in 66 and 67.



If you pay close attention to the connectors (as shown above) you will see that for the R2AM4 used in the 1969 and 1970 model years, the regulator had the 'male' spades, 
Starting with 1971, the regulator  had female spade connectors - this is also when they changed over to alternators that used an internal diode trio, or field diode instead of the isolation diode on the outside. The change in connectors prevented using the incorrect regulator with the different alternators.
 
AMC used Motorola alternators that had external isolation diodes, the famous red plates on the back, up through 1970. Those require a regulator meant to work with that diode due mostly to a 1 volt drop across the diode. That would be the early TVR series (TVR12AM18 for AMC) and the R2 series, shown above and below.
The 8R series is meant to be used with NO isolation diode - AMC used alternators with no isolation diode (red plate) starting in 1971.(Do be aware, however, than an 8R series was used with 1970 Fleet)
*Note the subtle differences between the R2AM4 and the 8RB2005.  Male vs female connector on the regulator. Tricky! If you use a 1971 or later alternator on your car, you'll need to use the 8RB2005 regulator and change gender on the connector!
 
Here we see the regulators and the associated wiring harness connector ends:
 
The TVR12AM18 used in the early 60s will have 3 bullet connector.
They changed to the R2AM1 in 1966. This was later superseded by the R2MA2 regulator that had the black tag but the same 4 bullet connector as shown with the R2AM1 above.
R2AM1 had the teal tag, R2AM2 had the black tag. (there was also an R2-1 from Motorola)

In the first quarter of 1969, Motorola released a bulletin stating that beginning in the spring they would no longer name the models based on OEM use (as an example, things Motorola made for AMC will have 'AM' somewhere in the model number for several years)
Starting in their spring 1969 production there would be standard model designations. Thus the AM would be missing from alternator and regulator model numbers.

Alternators prior to the 1970 model year used the A12NAM model series - where A is the series, 12 the voltage, N is negative ground, AM is American Motors and the rest indicate pulley, how the rear frame is "clocked" and so on.

For the 1970 model year (and later), AMC used the new Motorola model designations - all beginning with 8AL, which is the series of alternators where the last character in the model number indicated amperage output - in 1970 K was 55 amp and F was 35 amp.

 


Edited by billd - Sep/13/2012 at 11:00pm
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Direct Link To This Post Posted: Jun/16/2012 at 1:09am
Thanks much for the post billd, I can use all the info I can get.
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Direct Link To This Post Posted: Feb/06/2013 at 7:00am
A quick update on alternator wiring/connections as used by AMC.
A trip back in time, this is for the "early Ramblers" with alternators. note that for a while the car could be equipped with either generator OR alternator. The wiring diagrams in the books typically show both possibilities in one schematic.
The first electronic regulators from Motorola did not have the "exciter" resistor internal to the regulator. It was a discrete component mounted on the inner fender under the hood. This is not to be confused with the ignition resistor, also a discrete component at that time - before the resistance wire was used.
These systems will use the 3 wire regulator as shown in the pictures in my first post in this series. There was also a regulator used that had the 3 bullet connector and 2 yellow wires separate from the other 3 wires. This was a "retrofit" unit designed to replace the earlier TVR series. It had the resistor internal to the regulator and the 2 separate wires allowed bypassing, and thus removal, of the external resistor.
The resistor allowed for field excitation in the event of a dash warning light failure. Normally the orange wire runs from the dash ALT light to the aux or regulator terminal on the alternator and the orange wire into the regulator. This furnishes the current needed to "excite" the field and get the alternator charging since the rotor core is constructed so as to not hold residual magnetism.
Should the dash light bulb fail, this meant that the alternator may not charge.
The solution was to add a parallel circuit fed by the ignition feed going to the ignition coil primary + terminal. To drop the voltage to a level similar to that of passing through the dash light, they used a resistor in series. In this way, they ensured there would be excitation for the field and the alternator would charge - and either path would supply approximately the same voltage, thus current. The resistor also reduced the chance of the engine not shutting off in event of a failure in the alternator (shorted diode(s)) or problem with the regulator feeding back enough current to the ignition to keep the engine running after you turned the key off.
(It didn't always work, so if the engine won't shut off on these early Ramblers, try pulling one of the wires off the charging system resistor.)

Here is a typical alternator schematic for 64/65 Rambler - Classic, American, Ambassador, etc. Note the charging system resistor is circled in yellow. I have traced in red the path that makes it possible for an isolation diode failure (shorted mode) to cause the engine to keep running when the ignition switch is "off". Unplugging the charging system resistor will let the engine "die". Because the battery is directly connected to the isolation diode, should that diode fail "shorted", it would feed battery current to the ignition system through the path I marked in red  ->




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Direct Link To This Post Posted: Mar/04/2013 at 2:58pm
Another update, this related to AMC models in the early to mid 60s with Motorola charging systems.
As stated above, the first models/years to use the Motorola alternator used the 3 wire transistorized regulator with the "TVR" designation (simple enough - Transistorized Voltage Regulator")
TVR12AM18 is a good example and is shown below. This is a transistorized voltage regulator, 12 volt for American Motors, model 18 of the series. These used an external resistor to provide field excitation.
- A very early AMC/Rambler electronic voltage regulator by Motorola ->



This post discusses the "retrofit" or replacement of the TVR series with the newer (newer back then) regulator model R2-1. This model incorporated an internal resistor which negated the need for the external resistor and extra wiring.
The R2-1 looked much more like its successors, the R2AM1 and R2AM2 models.
This is an example of the R2-1 regulator as used by "Rambler" to replace the TVR regulator - Note the same 3 bullet connector, but the addition of 2 yellow wires -



This is the bulletin these newfangled regulators came with -



The wiring is very simple, and you can see they are paving the way for the use of the R2AM1 regulator in size, mounting, etc.

So the early AMCs went from using the TVR series, to the replacement for the TVR, the R2-1, then moving on to the R2AM1, and that was later replaced for 67/68 use by the R2AM2 (which again was much like the R2AM1 it replaced, but with black tag and different voltage setting)
Then in 1969 and 1970, the R2AM4 with the different connector.
In the spring of 1969 Motorola announced it was moving to a new model numbering scheme, dropping the OEM designators from the model numbering system in favor of a more uniform (and cheaper to stock) universal system - meaning the alternators then later the regulators would no longer have "AM" in the model number.


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Direct Link To This Post Posted: Sep/15/2014 at 7:12am
I thought I'd post some additional information related to charging system wiring, regulator connections and so on.
It appears, but I need to confirm, that some AMCs of the mid to late 60s (years yet undetermined, models yet undetermined), had a second regulator connector at or near the firewall.
This was wired in for those vehicles which had the AM or Prestolite charging systems where the regulator was mounted on the firewall and not the fender area.
So if you see a connector like the R2AM1 regulator used near the firewall, it's likely there for cars with the Prestolite or AM branded charging systems.
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Direct Link To This Post Posted: Nov/16/2017 at 9:53pm
Additional regulator information. Above we discussed the regulator model numbers, roughly when each was used, the connector types and so on. 
Here are the what I call "room temperature" regulated voltage specs for each. I won't include ALL of the info as each has a range, depending on the temperature of the regulator which causes the regulated voltage to go up as the temp goes down, and the voltage to go down a bit as the temperatures under the hood go up because a colder battery is harder to charge. I'd have to show the range or SLOPE as Motorola called it, of each, and those aren't important to anyone but me - I would assume.....   Confused

OK, I won't start back in the beginning - the TVR series used in the 63/64 models, we'll start with the R2AM1 - I'll show model, and then the regulated voltage at normal under-hood temps on a nice summer morning in Iowa.
KEEP IN MIND UP THROUGH R2AM4 was used with the isolation diode which dropped output approximately 1 volt so a regulated voltage of 15.2 for example meant 14.2 at the battery!

R2AM1  -  15.2
R2AM2  -  14.8
R2AM4  -  14.8
8RB2005  -  14.0
8RH2003  -  14.2

Why the differences? Battery technology! I will update the battery fact post to help explain this, but here is an example - 
In the first half of the 1970's, calcium was added to lead-acid batteries. This reduced "outgassing" and allowed batteries to go extended periods without the addition of water (and it heralded the so-called "maintenance free batteries" but the calcium addition caused the batteries to require a bit higher charging voltage. Note the last two regulators above - the 8RH2003 was used starting in about 1973 and likely explains the two tenths of a volt increase. GM set their regulated voltage at 14.8 when equipped with their new Delco Freedom II batteries. So - not all GM regulators were set the same!

So in short, a battery isn't a battery isn't a battery is't a battery, and a regulator for a "twelve volt system" isn't necessarily the same as a regulator for a "twelve volt system". 

When I was a tech, way back in the prehistoric days when our hair was down to our shoulders we had to be careful to match regulated voltage to battery make-up/technology. 
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