Alternator

L

LarryinWA

Senior Member
I would like to change my older 3 wire to a single wire to clean up the wiring. Any advantage to one or the other? Does anyone have a wiring diaghram to show how to do this? Thanks
 
Probably your 3 wire setup uses the ignition switch to power the regulator,start it charging(better setup), the 1 wire can take a little power even when the car is shut off ---perhaps creating the "need" for a shutoff switch --search the past discussions, there are many, I like the reliable original generator, but do have a diode cutout, and halogen headlight bulbs, for me the alternator takes too much attention to keep the belt tight and the battery charged.
 
why does it take to much attention to keep the belt tight? doesnt it have an adjusting arm going to it to adjust and hold it in place just like a generator? and altenators will keep you batter charged and charged quicker because they put out power at low rpms unlike a generator which has to be wound up to put out there power, an altenator will not let your battery go dead driving around town at nite cruising and stopping at stop lites and idling with the head lites on, a raido, heater and many other convenieces added to a model, why do you think they put altenators on newer cars, were they cheaper to make? no the are more effecient for motoring, and more reliable, i have a 2003 van with over 100,000 miles on it and i have never touched the alt, the battery has never gone dead till after 7 years, it was just used up, but it was never dead because of the alt, and you can walk into any parts store wrecking yard or service station and get an alt, can you do that with a gen? alt are maintance free, no oil lite bushing to oil every 1000 miles or so, i think gens look neat on old cars but lets tell the truth about them, they are more reliable and easier to obtaini understand you cant run an alt on a show car but for an every day driver, they are the way to go, now on the the one wire alt, they have reliabllity problems, for one some have to be reved up to start to charge, and they have a habit of not complety disconnecting from the power source that excites them, the battery, and will run down your battery over nite or in a few days of not driving your car, a 3 wire alt has only one more wire than the one wire,and it can be routed so it cant be seen, and that one goes to the ignition to turn it off completely when the key is turned off, the 3 wire is not excited till the key is on, now dont chew my head off im just trying to explain the differences, what you choose is up to you and no one else
 
I am sure the alternators are cheaper to make and get higher output. They were also loved by the mechanics because they tended to go bad more often. Especially the delco unit, why do you think they are so cheap?

Let us go back in time.

Open up your shop manual for your XXXXX car with a standard alternator and V belt. You will find a standard for tightness of the belt. I was taught that you should not be able to turn the fans on the alt pulley. If you tightened to the spec with the belt tension tester then it would be tighter. You will also note that those older cars had the belt do a substantial wrap around the alternator so there was a large contact patch. The v belt would expand as it did the wrap around to give a tighter grip. Remember the squeal you got when it was a little bit loose and you just started the car?

On the A we have a relatively small pulley diameter and a small arc of belt contact. Even on very tight belts you can move the pulley fan with your fingers. Most are so loose you can move the pulley with your pinky. I have even gotten a full spin on some cars.

Of course, if you tighten the belt really tight you can run into troubles with the water pump.

So what good is a 60 amp alt if the belt is not tight enough to allow for 15 amps? I am pretty sure you are not going to see 60 amps, ever. I will admit I have never had the chance to some real measurements on the output of the alt.

SOOOO
Please tell me how you can expect any kind of charge rate when the belt is so loose?

Now for any kind of arguments that you need some special charge rates for day to day use, how many really need that?
In the last 40 years of having A's in the family we have never had a charge problem. Oh, we have had exactly one charge problem when my then 15 year old brother (kurt in NJ) had the cutout stick on and the gen threw the solder. It got a temporary repair and has not been touch since.
 
My experience: My 6volt, positive ground, one wire, 30 amp alternator was TOTALLY sufficient. I NEVER EVER had to put a battery charger on it!!
Minerva sat for 4 months while I was in the horsepistol, and rehab, NO trickle charger, and a 6 year old group 1 battery, no cut off switch, and fired off as if she had been driven yesterday!! (To me, this blows the theory that a 1 wire, self exciting alternator has enough "draw" to run a battery down in a few days.) I also think it would be a rare case that anyone would ever need a 60 AMP alternator. Bill W.
 
lol can you show me gen that has 100,000 or more miles on it? modern alts do that every year on millions of cars, and do you do a lot of nite crusing with your lights on at 5 or 10 miles and hour like most cruises are done in town, do you have a radio a heater? yes the belts may be looser on an older car so are dead batteries, if the belt is slipping the gen is not turning and charging, neither is the water pump, maybe a reason for over heating? car manufactors are not dumb, they upgrade the systems for a reason, and its usually because of better performance and less maintance, they went to an alt because they had to, just like they went to radial tires, detergent oil and hydralic brakes, they just work better, so lets just agree to disagree and leave it at that
 
Last edited:
The one wire alternator on my Model T hums very quietly when the engine is stopped. I have a shut off switch for the battery. With the battery shut off switch open..no hum. With the battery shut off switch closed...a quiet hum from the alternator. My battery has never gone dead from the alternator because I have never left the shut off switch closed after I was done running the T for the day. I imagine that quiet hum would eventually kill the battery if the switch were left closed over night, but it hasn't happened to me yet.
 
The amount of current draw on a GOOD alt. is very, very low, over time it may drain a battery, however it is not going to happen in a few weeks. One common problem is one of the diodes going bad, this will not only reduce the output current it may allow a sharply increased current draw. Alt's run for many thousands of miles, under a very hot hoods they are very reliable. Try to get a generator to put out 30 amps for very long and see what happens. I use both, if you want orginal, keep the gen, for the "driver" I like an good alt, lights works better.. you can put in better bulbs for more light output.... good lights = safer driving at night.
 
if the alt hums when engine is shut off its defective, replace it before it leaves you stranded some where, and a defective 1 wire alt can drain the battery over night, it has happened to me, got rid of it and bought a 3 wire, best thing i ever done
 
Last edited:
I've put dozens of Delcotron alternators on equipment over the years.For most things,tractors,crawlers,power units,etc.I just put a one wire regulator in,costs about $18.To make them a 6 volt positive ground setup I have to buy a $22.regulator and a diode plate.I forget how much they cost.Unless there is something wrong with the alternator the parasitic drain is minute.It is a lot less than I always thought it was.This afternoon I went out and started my woodchipper.It has a John Deere engine,and I put on a Delcotron with a one wire regulator in it.I parked it at the end of November and it spun right over today.No charging,no battery shutoff,nothing.I know of quite a few A's with alternators,they don't run the belts too tight,and have no trouble charging.Some worry about the fact that some won't charge after starting,until the engine is revved.They don't want to rev a cold engine.So don't rev it.There is absolutely no reason that car has to be charging instantly.It will start charging as soon as you drive off,your battery won't be dead,you can drive it all day at a small discharge.My A's all still have generators,if I was to want electronic ignition or other accessories I would put an alternator on.I think the days of the Delcotrons being stocked in the parts stores are numbered.The local Napa does not stock them.If something does not sell X amount per month it is not stocked.They are in the warehouse though,so they can have one in a couple of hours.
 
I bought a power house generator and plan to install it in a few days. I looked inside and they have five brushes and they will put out 26 amps. They are neat looking and use a cut out. I do not want a bunch of electronic stuff on my "A". The alternators require a high rpm to put out a good charge. That is the reason for the small pulley. If you are running an alternator on a v/8 you need a special pulley to run a fan because the alternator needs a small pulley for rpm. Alternators do not look good on an "A" or a v/8. The belt tension for an alternator has already been discussed.

I like tinkering on a old Ford and do not mind oiling the and greasing and wiping down the engine compartment.
 
You must log in or register to reply here.
Back
Top