MasterGen 6 volt alternator in generator housing

[grumppyoldman]

I'v got the MasterGen 6 volt alternator installed and working great. It looks like the original generator. Fit like the old bad generator and puts out 7.2 volts at idle, 50 amps. at idle 55 amps crusing and 60 max. but my head lights still dim at idle. I guess I'll put some horn relays in to see if that helps get more volts to lights. Al

[JSeery]

Think we already went through checking the grounds, correct? Grounds, connections and wire size is about all there is.

[Kurt in NJ]

How did you test the amperage output?
Have you measured the voltage both at battery, and at lights
If it's really making 7.2 volts at idle what does it make off idle---- for the lights to dim at idle the voltage has to change

[grumppyoldman]

The final test on the amps. was dont by the manufacturer and tagged on the alt., the battery shows 7.2 amps. and when I raise the RPM's the lights get brighter. Yes J. every ground connection has been cleaned and coated with an electrical grease, after the connection was tightened.I haven't checked the voltage at the head light sockets since the installation of the new alt., but it was lower than 6 volts when I checked it earlier. Doing so much I can't get to all of it yet, but will get there . There was a thread some tiime back about using relays to get more voltage to the lights. will try that when I get a round tuit.Al

[Kurt in NJ]

I think you need to do on the car output test, if the alternator actually puts out 50 amps at idle you shouldn't have dimming at idle unless your lamp load is over 40 amps
Many times alternators are amp rated "cold", and some do close to the rating on the label cold, the real hot output is much less(a 100 amp rated special high output tested at a real 60 amps hot)------ this is why I asked if the output was tested for actual output

A friend has a Packard, it had dim lights, the previous owner had tried ever kind of "improved " light bulbs, and a new wiring harness, still dim, i traced out the volt drop to rusty nuts on the ammeter--- 4 new nuts made any light bulb bright, and fixed the turn signal blinking

Generator amp ratings are hot ratings so you get that amperage regulated by the regulator, most alternator ratings are cold and start dropping as windings warm(in less than a minute on test machine that 100 amp alternator was struggling to make 60--- I called the company that made it, they said-- normal, not having a problem)

[rotorwrench]

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Generators and alternators both require some form of control on their output. Neither should generate any amperage that is not needed by the system. In other words, they are controlled to generate the power that the system needs to function at any given usage level, no more and no less if function is normal.


Ford used to size the drive sheaves to control the rpm that the generators turned. They would speed up the generators on low rpm engine applications and slow down the higher rpm engine applications.


Alternators also need to function at an rpm that will allow them to both start up its generating process and give a longer reliable service so the same thing applies to drive sheave selection as it does for generators. Depending on the type of voltage & current control system, some alternators have to have a fair amount of rpm before they will start to generate power. The 12-volt conversion alternator I have on my old 850 Ford tractor has to have the rpm boosted up a bit before it will start charging the battery. It has an actual ammeter in the system so a person can see the indication when the alternator comes on line. It will show a slight discharge then it will pop up to 15-amps until it tapers off after the battery is recharged from the amperage utilized for the starting process. This particular alternator has the built in solid state alternator control unit for single wire operation. Some alternators start charging at a lower rpm than others.

[Kahuna]

Rotorwrench
I installed a small Denso Alternator (55 amps) and drive it from the rear U joint, on my 32 Tudor sedan. I converted the Banjo to open drive.
I just guessed at the pulley size for the drive part as I didn't want the pulley to hit the
body pan when the suspension compressed. It works great and turns on at about 15 MPH.
You can see it as the volt meter reacts.
Been fine for the last 5500 miles
Jim

[john in illinois]

I have a Whitney alternator in a Ford case with a Ford fan pulley ( 3+"). The pulley is larger than a regular alt. It starts charging at pretty fast idle. No charge at idle. This is normal and always keeps battery charged.

What size pulley does yours have? They have to have enough rpm to excite.

John

[whizzernick]

never heard of them . are they hard to get ? where ?

[grumppyoldman]

Ordered thru Mac's, a little wait time but worked out ok. Don't know pulley size but charges fine.

[john in illinois]

...

[JSeery]

Originally Posted by whizzernick

never heard of them . are they hard to get ? where ?

They are custom built and take a while. http://www.ejwhitneyco.com/automotive.html

[FL&WVMIKE]

Originally Posted by grumppyoldman

I'v got the MasterGen 6 volt alternator installed and working great. It looks like the original generator. Fit like the old bad generator and puts out 7.2 volts at idle, 50 amps. at idle 55 amps crusing and 60 max. but my head lights still dim at idle. I guess I'll put some horn relays in to see if that helps get more volts to lights. Al

Relays on headlights are always a good idea. It's a popular modification on early mustangs, as the power has to go all the way from the battery, through the switch in the engine compartment, and then to the lights. Installing relays with shorter, fatter wire definitely brightens up the headlights on mustangs... I would assume it would be even more impressive on a car with 80 year old 6V wiring.

Of course, taking care of all the basics is still important.

Good Luck!