What is this on my generator

[bmklawt]

What do I have on my generator, should I leave it or change it out for the semi-conductor cutout I bought.
Does anyone know what it says under the paint, all I can read, top line POS, second line, BAT, GND, ????

[TRDxB2]

It is an early cutout rectangular instead of round

[RajoRacer]

I don't think so Frank - might be a re-fitted voltage regulator off a ????

[TRDxB2]

I don't think so Frank - might be a re-fitted voltage regulator off a ????

Actually I don't disagree with you. Your question prompted me to do a bit of surfing the internet and I did I find a picture of a similar looking repro for a 1928 Chevy. But the only way to tell for sure is to see what's inside the box. So its "most likely" a cutout.
Automotive voltage regulators started come into prominence in the mid 1930's https://ethw.org/First-Hand:The_Story_o ... _Regulator

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The VR's do come in square or rectangular containers. Ford has some square cutouts too

ford cout.png (356.15 KiB) Viewed 2252 times

[Alan Long]

Over the years many wonderful (and not so wonderful) replacement cut outs have been used from various vehicle models and Makes. We used to use the ones of the Ford Prefect as it had a Ford Script on it. If your Generator is a standard Model T one, the John Regan design electronic cut out / voltage regulator is the way to go. Mine has worked well for years and has the Ford Script on it!
Just my experience. Alan In Western Australia

[John iaccino]

I have a similar regulator on my generator. The one that I have is meant for charging 6,12, or 24 volts and was purchased at a motorcycle shop. I am running a 12 volt battery. The stock Model T generator charges 12 volts very nicely, but at half the amps.

[RajoRacer]

Could be Frank ! I have an original Ford script rectangular cut-out that Ron the "Coilman" converted to a diode for me for our '19 Centerdoor.

[otrcman]

I am seeing the words, "cutout" and "regulator" used rather interchangeably in this thread. You need to know that they're not the same thing.

Model T's originally had cutouts, which are nothing more than a reverse current relay to prevent running the battery dead when the engine is not running.

A voltage regulator is a late 1930's improvement. It incorporates three relays rather than just the one.

The first relay in a voltage regulator is a reverse current relay just like Model T's had. That relay is to prevent running the battery dead just like a cutout does.

The second relay is to actually taper off the generator voltage as the battery comes up to full charge. It prevents over charging of the battery.

The third relay is an overcharge protection device to protect the generator from over heating when trying to recharge a very low battery.

The "John Reagan" is a wonderfully modern version of the voltage regulator which is highly reliable and more precise in controlling the battery charge. Your battery will usually have a far longer life with a Reagan regulator.

[TXGOAT2]

As I understand it, the single element devices are cut outs. A cutout is nothing more than an automatic switch that disconnects the generator from the battery when generator output is below battery voltage. It has no voltage or current regulating function. An original type voltage regulator will have at least 2 elements, one being the cutout and the other being a voltage regulator. The function of the voltage regulating element is as described in the post above. The later, 3 element regulators added a third element which regulated maximum current. The 3 element units are best. Any generator with an original style electromechanical voltage regulator will have an external field winding terminal in addition to the armature (output) terminal. Some generators have 3 terminals: armature, field, and ground. (Arm, Fld, Grnd, ,A, F, G)

[TRDxB2]

I am seeing the words, "cutout" and "regulator" used rather interchangeably in this thread. You need to know that they're not the same thing.

Model T's originally had cutouts, which are nothing more than a reverse current relay to prevent running the battery dead when the engine is not running.

A voltage regulator is a late 1930's improvement. It incorporates three relays rather than just the one.

The first relay in a voltage regulator is a reverse current relay just like Model T's had. That relay is to prevent running the battery dead just like a cutout does.

The second relay is to actually taper off the generator voltage as the battery comes up to full charge. It prevents over charging of the battery.

The third relay is an overcharge protection device to protect the generator from over heating when trying to recharge a very low battery.

The "John Reagan" is a wonderfully modern version of the voltage regulator which is highly reliable and more precise in controlling the battery charge. Your battery will usually have a far longer life with a Reagan regulator.

I believe that Reagan VR is just a two stage VR. One relay for the cut-out function & the second to regulate voltage. The 3rd Brush is used to regulate the current and its settings are described in his VR instructions. Voltage is the primary factor to charge a battery while amperage determines the rate, time, at which it takes to charge the battery.

[speedytinc]

As I understand it, the single element devices are cut outs. A cutout is nothing more than an automatic switch that disconnects the generator from the battery when generator output is below battery voltage. It has no voltage or current regulating function. An original type voltage regulator will have at least 2 elements, one being the cutout and the other being a voltage regulator. The funtion of the voltage regulating element is as described above. The later, 3 element regulators added a third element which regulated maximum current. The 3 element units are best. Any generator with an original style electromechanical voltage regulator will have an external field winding terminal in anddition to the armature (output) terminal. Some generaators have 3 terminals, armature, field, and ground. (Arm, Fld, Grnd, ,A, F, G)

My simple explanation.
Mechanical(original type) & electronic (diode) cut outs act as a one way valve to keep battery voltage from feeding back into the generator. Neither "regulate" the state of charge. Both can over charge a battery. Both rely on the proper output setting in the generator.
The mechanical C/O electromechanically closes a set of points once the generator output gets high enough (Just above battery voltage) if properly tuned.
A voltage regulator reads the battery voltage & cuts back on the amount of voltage going into the battery. The battery cant be over charged. Again, if properly set.
The fun projects regulator(looks like a stock cutout) read the voltage & pulses off(pulsing to ground) to maintain, but not overcharge the battery, functionally acting as a modern voltage regulator does.

[otrcman]

We all learn something new ever day. Hopefully, that is.

Frank B. and John K. informed me on something I didn't know. That is, that the Reagan (Fun Projects) regulator doesn't have the third (overvoltage) function. It never occurred to me that the Model T generator already has the third function built in by the nature of the three brush design. Newer type two brush generators don't have that function as they don't have the third brush.