Generator output

[Brian in Wheeling]

This question is probably for Tom Wesenberg, but anyone who knows feel free to chime in. What should be the output ( in volts) from the generator at a fast idle, with one of Tom's internal regulators fitted? (Also, assume a fully charged battery with no drains) How and where does one measure this output? Digital or analog multi-meter, or does it matter?

Thanks,
Brian

[Mike V. Florida]

Since the battery is used as a regulator in the Model A the Gen output would be just over the battery voltage as measured with an analog meter as a digital meter will jump around too much for a good solid reading.

[Tom Wesenberg]

Measure the output voltage at the output stud of the generator, and as Mike said it should be measured with an analog meter and about 7.5 volts. If you have a diode cutout it will be about 8 volts with the wire cut on the EVR. What does your's measure? Also take a reading on the output side of the cutout and it should be the same for an original cutout, and about .6 or .7 volts lower for a diode cutout.

With a good battery fully charged the ammeter should be reading just a hair over 0. Mine reads about 6 amps after first starting the engine, then within a couple minutes has drifted back to near 0, and my battery is still the 10 year old junk yard battery and going strong.

[Brian in Wheeling]

Thanks, Tom and Mike. Will do as suggested.
Brian Warmuth

[H. L. Chauvin]

FWIW:

Humble opinion:

Buying a Model A voltage regulator to replace a non-working cut-out can be thought of like putting cash in an interest drawing savings account.

A. Batteries last longer because they are not boiling from an excess generator/cut-out charge rate; &,

B. Generators last longer because they are not putting out excess current to boil batteries that are already fully charged.

C. The voltage regulator pay back may be recognized from the cost savings from not needing to buy as many new batteries so often; & the cost savings from not needing to re-build generators as often.

[marc hildebrant]

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H.L.,

The voltage regulator is not the same as a cut-out. Did you mean to say that the Model A Voltage Regulator is a better device than using the third brush ?

Marc

[Purdy Swoft]

I'll say that it is!!! Besides what H.L. says, The voltage regulator will allow more amps on demand for the headlamps. A voltage regulator saves the owner the task of adjusting the third brush. Being as the battery that is used (6,8 or 12 volt) sets the voltage, it is the amperage output that counts.

[mralternator]

keeping in mind the Generators inability to produce more amperage with out over heating its self and the low output at a low rpm

[marc hildebrant]

With regard to a voltage regulator, the voltage regulator sets the output voltage of the generator independent of the battery voltage. If the regulator voltage is higher than the battery voltage, then current will flow to the battery (Amp meter will show a value). Once the battery and the voltage regulator value (Set by Tom's circuit values) are the same, then no current will flow to the battery (Amp meter shows a 0 value).

Marc

[Purdy Swoft]

Actually, the battery controls the voltage output. the regulator controls the amperage. The amperage doesn't increase with battery voltage. Being as I don''t use any electrical accessories, I get by very well with an 8 to 10 amp maximum output with a 12 volt battery. I get fast cranking, not because I really need it but because I like it. A slightly weak six volt battery may not always have enough power to run the starter and fire the ignition at the same time. Twelve volt bulbs generally cost less and are easier to locate on the road. All of the available regulators are good. I use the Fun Projects can style regulator because it is easy to set up, takes the place of the cut out and is available in 6,8 and 12 volt

[Purdy Swoft]

Originally Posted by mralternator

keeping in mind the Generators inability to produce more amperage with out over heating its self and the low output at a low rpm

I agree that the alternator out performs the eighty year old generator. The alternator charges at idle speed and is capable of way more amperage output for accessories and the more powerfull Quartz halogen bulbs. The original generator is capable of powering the less powerful 35 watt halogen bulbs that fit the original sockets. Running the original generator on 12 volt 8 amps doesn't create that much heat and with the more powerful battery, I don't notice the diming of headlamps at idle speed like with a 6 volt battery. The extra volts at the battery seems to help. I do use the air scoop band cooler on the generator to keep the commutator cooler. Being as the amperage output is lower with 12 volt, the cooler band isn't mandatory. I've used alternators. I installed a 6 volt sixty amp alternator on the coupe eighteen years ago, it still works, the quartz halogen headlamps are as powerful as a modern car.

I prefer the generator . The generator is correct for the car and I don't get the negative comments. I rebuild my own generators , I don't even try to repair alternators. I've never had a problem with my rebuilt generators. It is a real novelty for me, being able to run the original, unmodified generator on 12 volt in our roadster.

[marc hildebrant]

Purdy,

There are two types of regulators, voltage and current. The type that Tom W. makes regulates the voltage. You may have a current regulator.

I have designed and built electrical regulators. In addition, I have seen the schematic of the fun projects and it is a voltage regulator.

Voltage regulators use a Zenior diode or other type of device to establish a fixed voltage. This fixed voltage is then compared to the output voltage and the current to the field or the duty cycle of the generator voltage (Fun Projects) is varied to keep everything equal.

It is possible to regulate the current instead of the voltage, but then your Amp meter would show a CONSTANT value.

Marc

[mralternator]

PURDY, Yes Agreed that if you keep the amperage low ( below 10 is safe ) you shouldn't have too much of an over heat problem, just when added accessories demand more amperage , would there be a problem, and YES I understand fully the appearance factor of the original Generator, Definitely the number one Difference, I truly hope to actually Have an Alternator in a generator kit produced at a reasonable cost soon. to eliminate the appearance problem associated with an alternator being used, and to bring the numerous benefits of having an alternator for the charging system

[marc hildebrant]

The original Model A charging system is a "constant current" system. For this system to work, you do need a load or the battery has to be connected to the generator. The third brush sets the amount of current that the generator will but out. Since the system is "constant current", the battery voltage will rise as time goes on and loss of water will occur in the battery.

The use of voltage instead of current is much better as the battery voltage , once charged, can now be set to the value that will keep it charged but not high enough for loss of water.

The mechanical systems in the 50's and 60's supplied a fixed voltage and some (three coils) would also linit current if it got too high. But, they were voltage regulators.

Marc

[Purdy Swoft]

The original model A charging system is a constant current system when used with a cutout. The cutout allows the current to flow in one direction. When the engine RPM increases to the point that the generator begins to charge, the points in the cutout closes. When the points close, this alows the charging current to flow back through the hot wire on its way to the battery. When the points in the cutout are open, as when running at LOW rpm no currant flows in either direction. When the cutout is used the generator will charge at a constant current at whatever rate that the third brush is set for. When a regulator of whatever type is used, it will allow the generator to cycle current on demand. It really doesn't matter if the regulator replaces the third brush, moves the third brush, has three coils like the 40s -early 60s box type regulator or uses a different method, it is still regulates current flow to the battery. The Fun Projects voltage regulator cycles current on demand to the battery. No matter whether you like it or not, A rose is still a rose, no matter what you call it. Insert smiley face. The old type three coil voltage regulator as used mostly in the forties and fifties can be wired to the model A generator and will work well, if you know how to do it. I won't go into the hook up but if you don't believe it, just ask Tom W. .

[marc hildebrant]

Purdy and others.....

Maybe the confusion you have is over the terms voltage and current with regard to regulation. These terms are different and mean different things.

Voltage regulation keeps the voltage constant, independent of load. Thus a volt meter would stay at a fixed value and the current (amps) would change depending on the load. When a Model A is started with voltage regulation, the amp meter jumps up and then slowly goes close to zero as the voltage on the battery rises. This is the way that today's Model A products work.

Current regulation keeps the current constant, independent of load. Thus the volts change as the load changes. In this case, the amp meter stays fixed and the voltage rises up to a value that keeps pulling amps. The original Model A system was this type.

Voltage and current are not the same. The old three coil mechanical ones used one coil for a cutout, one to regulate voltage, and one to limit the current (not really regulate).

Fun products and other regulators are of the voltage type. They keep the voltage constant...not the current.

Marc

[Purdy Swoft]

Maybe its terminology.The Fun PROJECTS regulator cycles the charge to the battery like any other regulator does. you make it sound like the Fun PROJECTS regulator is only a cutout, not so. The various voltage regulators operate in different ways but accomplish the same task. The task being to allow the charge rate to fluctuate from low to high amps as needed without the need to move the third brush. I won't argue this fact, I can see that it is useless. Smiley face.

[mralternator]

AS an Alternator kit charges perfectly and handles any other demands for output, a total elimination of problems instead of nit picking 1 problem at a time, simplicity at its finest

[marc hildebrant]

Purdy and Others.....

The fun project device performs a "cut out" function and voltage regulation. The voltage regulation uses a "shunt" type of regulation since the device does not have access to the field winding.

It's a clever device that performs a needed function while preserving the antique look.

Marc

[Purdy Swoft]

Thanks Marc .