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Definitely not! Depending on how things are connected inside the regulator you will either have nothing work or a short if the wires are reversed.

The ARM (or GEN) wire is the current and voltage out of the generator and goes thru two current sensitive coils in the regulator and a voltage sensitive third coil. One current coil is hybrid with current and also a low voltage shunt coil on the same core to initially close the set of contacts which comes in to connect the generator to the battery or opens to totally disconnect the generator from the rest of the electrical system when the engine is turning too slowly for the generator to work or is off. The second current coil senses when amperage out out of the generator is too high and opens a set of contacts in the field circuit to stop the generator from producing as much current. The third coil is voltage sensitive and opens or closes contacts when the voltage is incorrect.

The field wire connects directly to the generator field coil which get power from the generator on one side with the connecting wire going thru two sets of contacts in the regulator that connect the other side of the field coil to ground . Once the generator is putting something out on the ARM wire, the current or the field coil in the regulator senses the amount of amps or voltage being produced and causes its set of contacts to continually operate to rapidly open and close the contacts to ground. When the contacts open two resistors, one of which had been essentially shunted out of the circuit are then active. The resistor which had been shunted connects directly to ground to provide a high resistance connection to ground which keeps the generator working but at a lower level, the other resistor always in the circuit provides a feedback voltage to sort of buck the voltage on the other end of the field windings to also modulate the field strength. The continuing change in field excitation regulates the voltage and current within a specific range.

Here is a typical generic diagram but each mfg will sometimes put their own spin on exactly how the circuit is connected to do the job.

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  Charging Circuit.JPG (67.88 KB)

If you simply polarize the regulator it will work either way. There are no diodes in it. However, I think the windings differ in direction according to polarity and that follows the left hand rule for magnetic field.

However, I never deviated from as built and the starter motor is DC and I don't know if it will run backwards.

The stock starter motors -- in fact all stock Packard motors -- will always turn the same way regardless of polarity because they are internally connected so the armature and field coils are always in the correct orientation for a specific direction. If the polarity is reversed they still turn the correct direction because both the field and armature are also reversed at the same time with the polarity change so the magnetic fields, while opposite, are still in the correct orientation for turning a specific direction. This can be observed by remembering all the cars which accidentally had batteries connected backwards with a negative ground. They still started and ran with the main issue being most would no longer charge properly because the generator was now incorrect.

If the car has been upgraded to one of the mini or hi torque starters with a permanent magnet field those will turn backwards if polarity is reversed. Also, any other modern PM field motor that might be installed will be backwards.

Howard, what is the type of voltage/current output of the arm and field wires not including the regulator?

I would assume just some unsteady DC voltage between the two.

The maximum output of an unregulated generator depends on the windings and varies with the brand and model of generator. The ARM wire gets the full output, the FIELD wire handles relatively little current as it only carries what the field windings need to provide the changing magnetic strength to the field shoes to regulate output to spec. This is evidenced by the ARM wire usually being a 10 ga and the FLD wire a 16 ga.

A standard postwar 6v automotive generator such as the type Packard specified can produce a maximum voltage in the low teens and a current approaching 60 or so amps. The generators when installed were typically regulated down to a max voltage out of around 7.5v and amps in the range of 35-45. The exact numbers varied by car model and brand of generator/regulator. A constant maximum output will produce enough heat to melt the solder connections in the generator so can only be obtained for a short time. One of the tests on non charging systems to prove if a generator or regulator is most likely at fault is to briefly ground the field wire. This will force a properly working generator to go to maximum output. If the voltage being measured across the battery when the ground connection is made jumps up by several volts it usually proves the generator is working and regulator is at fault. If there is no change then usually it is the generator causing the issue.

There are "heavy duty" 6v generators and regulators which were sometimes used in commercial vehicles. Other mfgs routinely used them on cars with AC because of the extra current draw of the blower motors but Packard did not feel the need for them. Those would be regulated to the same voltage range but amps out was usually somewhere in the 55-60 range.

A standard 12v generator would have max voltage out in the high teens to low 20s but the max amps out is roughly the same as the 6v model. Regulated output is spec'd at around 13.6v and 30 or so amps.

From the literature archive on this site, this service literature from Auto-Lite has a detailed description of how the 3 element regulators work.

packardinfo.com/xoops/html/downloads/AutoliteGenerators.pdf

That’s all great information and much appreciated as it gives a wider view of the functionality of a mechanical regulator but not directly related to this thread!

Actually Don I'm going to respectfully disagree with you there. For a regulator design that can properly switch between positive and negative ground (or adapt a design from positive to negative ground as we are doing), it's necessary to understand the complete electrical flow of the charging system, and Howard had corrected some erroneous assumptions I had made. Likewise, BDeB, thank you for posting that link. I had not seen that in the literature archive and it was much more helpful than other explanations I had found online.

Howard, considering that the armature wire would be negative relative to ground in a positive ground system, would the field wire also be negative, or would it be positive? Or AC current?

The generator is capable of either polarity as an output. It needs to be polarized in the correct orientation when first installed in a car or when disconnected and removed, worked on and reinstalled. It is suggested repolarizing be redone when any major component is replaced. Polarizing is done by having everything hooked up, engine and key off, and then momentarily shorting the BAT and ARM terminals on the regulator together. That action puts a high current surge directly thru the generator which partially magnetizes the field shoes. From that point on the generator relies on the small residual magnetic field having enough magnetism to enable initial charging when the engine is started. Polarity out will be dependent on how the N and S poles were aligned during the polarizing.

With the small residual magnetism, when the generator starts turning it will be able to produce a very low current and voltage which is enough to bring in the cut out coil in the regulator via the shunt winding. Once those contacts close battery voltage is then fed into the generator which strengthens the field enough that the generator starts producing a normal output which is then fed back out and regulated to spec by the other two coils in the regulator. Not having the correct residual magnetic field orientation is the reason most systems fail to charge after a battery is accidentally installed backwards. Of those that do work and manage to start putting out a high enough incorrect polarity, serious battery damage usually results if it goes on long enough.

Howard, as usual, thank you for the helpful info. I'm going over Don's design again to double check polarity things.

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However, this is slightly incorrect. The cutout relay on the VR completely disconnects the generator from the battery, so at least when the generator voltage is low, it is completely self-energizing, and it continues to self-energize when connected to charge the battery.