An alternator discussion

[Shoebox]

I continue to collect all the various needed components to convert my '51 Tudor to 12 volts. Got the 12v solenoid and relay for the OD, clock converted, bulbs, voltage drop for gauges, etc., which brings me to charging. I love the look of a generator on a flathead, but that being said, I'm going with an alternator with internal regulator, but which one? Years ago I installed a one wire 6v positive ground alternator on a previous '51, and it was real simple and worked well. I've read where some had the problem of the car continue to run when the ignition was turned off, but I didn't. I read that a 3 wire alternator is better because it is "excited" right away when started and begins charging right away. I am looking at an alternator offered by www.fifthaveinternetgarage.com which is a 3 wire US made unit that uses a Delta type stator resulting in stronger output at idle and low speeds. I'm not going to over research this (perhaps I already have?) but if anyone wanted to take a look at the above website and look at this alternator, that would be great. Any other comments, experiences most welcome. Thanks

[Ronnie]

https://www.youtube.com/c/alternatorman/videos


You will find lots of info here

R

[HambBurglar]

If you are going to use an internally regulated alternator, I would suggest saving yourself a lot of money and picking one up from your local parts store. Fifth Ave Garage is asking $245 for a 63 amp unit. Rebuilt ones likely start at around $50 plus a core charge. I believe the three wire unit is superior to the one wire for a couple reasons. First, you can find a replacement at any parts store. Second, the wire which “excites” the regulator should be connected to your wiring harness near the fuse box so that it reports back actual system voltage. If there is a voltage drop between the alternator and the fuse box, the regulator will increase the alternator output to compensate for the loss or heavy use of power. The one wire alternator is internally “excited” and only sees the voltage at the alternator. It doesn’t know or care if there is voltage drop down stream in the system. Ask for a 63 amp alternator from any mid 70’s Chevrolet. Many others will work fine as well but those should be readily available anywhere. My $.02

[Shoebox]

Originally Posted by HambBurglar

If you are going to use an internally regulated alternator, I would suggest saving yourself a lot of money and picking one up from your local parts store. Fifth Ave Garage is asking $245 for a 63 amp unit. Rebuilt ones likely start at around $50 plus a core charge. I believe the three wire unit is superior to the one wire for a couple reasons. First, you can find a replacement at any parts store. Second, the wire which “excites” the regulator should be connected to your wiring harness near the fuse box so that it reports back actual system voltage. If there is a voltage drop between the alternator and the fuse box, the regulator will increase the alternator output to compensate for the loss or heavy use of power. The one wire alternator is internally “excited” and only sees the voltage at the alternator. It doesn’t know or care if there is voltage drop down stream in the system. Ask for a 63 amp alternator from any mid 70’s Chevrolet. Many others will work fine as well but those should be readily available anywhere. My $.02

Hamb,
Thanks for weighing in on this and I value your thoughts, particularly considering your occupation. It appears you did go to Fifth Ave Garage website. What do you make of their "DA plug" that they speak of? I agree that their alternator price is spendy and I'm also aware of the return rate of many reman alternators from the big box auto parts stores, but yes not looking to spend more than needed. Thanks!

[V8 Bob]

I agree with HambBurglar on the advantage of a 3-wire over one wire.


The GM late '60s/early '80s 10/12SI alternators are the most common/popular, either original/rebuilt GM or brand new aftermarket from several companies.



The DA plug connects the two rear spade connections: #1 goes to the ignition switch through a diode and/or an indicator light (to prevent run-on with ignition off) and #2 goes to the main voltage distribution lug, the same location as the main output wire.


Open this link and learn more about these alternators and more.


MadElectrical.com - Mad Enterprises

[HambBurglar]

Sponsored Links (Register now to hide all advertisements)

Admittedly, I did not look deep enough into their Website to read about the DA plug so I went back for another look. The DA plug they talk about seems to be the 2 wire plug that connects to the alternator. The red wire that they are connecting to the output charging stud of the alternator is the wire I suggested should be connected further down stream in the electrical system. It will work the same as a 1 wire alternator if connected to the output stud. The second wire they are calling the “exciter” would have originally been connected to the dashboard “dummy” light on the 70’s GM. What the “lump” is that they install in that wire they do not say. I am no expert in 6 volt to 12 volt conversions so any input from those with greater experience is welcome. Here’s a website that is worth reading before you decide how to proceed. http://madelectrical.com/electricalt...evymain1.shtml

[HambBurglar]

V8 Bob! You beat me to it!

[HambBurglar]

Here’s a diagram stolen from the web that might help. https://studebaker-info.org/Tech/Diagrams/10-SIc2.jpg

[HambBurglar]

Also, that double female DA connector that plugs into the alternator should be very easy to find at most parts stores. I know I have bought them in the past. You do not have to have the plastic connector but it makes things look nice and tidy.

[Shoebox]

V8 Bob and Hamb,
Thanks for the great info and taking the time to look at what I was talking about. I am going to go with a 3 wire setup and quality new alternator. It's interesting to see both of you referencing me (for good reason) to Mad Electrical. I had many phone conversations with Mark when I was wiring a car with many accessories a few years back. He is a quirky but brilliant and a nice guy. I'm going to reread some of his material. Thanks again guys.

[Shoebox]

Originally Posted by HambBurglar

Admittedly, I did not look deep enough into their Website to read about the DA plug so I went back for another look. The DA plug they talk about seems to be the 2 wire plug that connects to the alternator. The red wire that they are connecting to the output charging stud of the alternator is the wire I suggested should be connected further down stream in the electrical system. It will work the same as a 1 wire alternator if connected to the output stud. The second wire they are calling the “exciter” would have originally been connected to the dashboard “dummy” light on the 70’s GM. What the “lump” is that they install in that wire they do not say. I am no expert in 6 volt to 12 volt conversions so any input from those with greater experience is welcome. Here’s a website that is worth reading before you decide how to proceed. http://madelectrical.com/electricalt...evymain1.shtml

Ok, so I DON'T want to connect their red wire to the output stud, as I want voltage sensing of the 3 wire setup, so it would farther in to perhaps the fuse/breaker block? The second wire (the lump is a diode by the way) would go where and do what as I don't have a "dummy" light? Would it go to ignition switch or could it go to + side of coil? Thanks again!

[V8 Bob]

Originally Posted by Shoebox

Ok, so I DON'T want to connect their red wire to the output stud, as I want voltage sensing of the 3 wire setup, so it would farther in to perhaps the fuse/breaker block? The second wire (the lump is a diode by the way) would go where and do what as I don't have a "dummy" light? Would it go to ignition switch or could it go to + side of coil? Thanks again!

The sensing or #2 wire goes to the voltage distribution location right along with the output wire. This can be in the engine compartment or under the dash. Jumping the sense wire to the output stud defeats the purpose of sensing. You want the 14.4 volts at the distribution point, not at the back of the alternator.


The #1 wire with the diode goes to the ignition connection on the ignition switch. A common #194 indicator light can also be used in parallel with the diode which can show charging issues in the future. This is how many OE vehicle were wired. This light can be placed under the dash like I have done on 2 of my cars if dash location is not practical. I do use a small dash mounted LED in parallel with the 194 on one car.



There is also a threaded boss on the back of the 10/12SI that could/should be used as a battery ground to eliminate any grounding issues with paint, chrome etc. to ensure maximum alternator operation.

[bobH]

And.... for us 'cheap' folks, I just go grab an alternator off the stash pile. I don't recall ever picking one that didn't work. Good enough for me. I also have a 'likeness' for the Ford alternator. Last two conversions I've worked on, I used the Ford version. Ford uses a wire loom that is wrapped, and 'somewhat' resembles 'one-wire' (ha). These last two were a 47 Ford, and a Ford engine in another make. Seemed like a Ford alternator was a 'natural'. Some would say 'no' on the Ford, because it takes an external regulator. I have only rarely found a need for the diode.

[Gene1949]

I "repurposed" a late Ford Taurus SVO alternator. 130 amp 3 wire internally regulated. At $20 been on the car for 15 years and many miles.
It's physically smaller than the GM or the original generator and the power output at low rpm (with the smallest pully you can find) its hands down the better choice.

The Op is absolutely correct in hooking the sensing wire as close the load center as possible.
I wired the '49 using the fuse/relay box off a 2000 Ford. All those old switches and the ignition now do pilot duty. I put the sensing wire on the main feed at that load center.

[Shoebox]

Big thanks guys for all the input,
I now know how I'm going to wire my 3 wire alternator, and will set it up with load sensing. Really appreciate all the info.