Workbench Wednesday. Delco 3 wire alternator.

Got a free 3 wire alternator. Going to hook it to the free lawnmower I recently got to make a 12v generator. Today we focus on how to wire it up.

[@rockvillemike6062]

OK, Here's the wiring facts, No1 and no.2 terminals: No1 terminal takes a 12v supply normally wired thru your ignition switch with a gm 194 bulb wired in series with it. it's purpose is to excite the field windings. I say excite rather than power because once the field is "excited" and the alternator starts producing power, the field is internally powered by the alternator itself. With a bulb wired in series and the ignition switched on and sending power thru the bulb it reaches ground in the alternator voltage regulator and lights the bulb because current is flowing thru it. When the alternator takes over supplying it's own power to the field, you then have 12v+ going into the bulb from both ends and you have set up a "balance of power" and no current flows thru either end so the light goes off. No.2 terminal is the voltage sense wire. It reads the voltage input to it and lets the regulator turn the field windings on or off to keep its' output at its' "set point", usually 14.7 volts. If it senses more it cuts out the field power, or senses less it connects it to provide power. That's how it regulates. If your plan is to make a generator I'd connect No:2 terminal at the 12v+ input terminal on the inverter you will use. That way it would sense any voltage drop there at that point and regulate accordingly. Just sayin' Mike

[@LIGHTOFTHEWORLD256]

This comment is better than the video itself thank you mike.

[@allischalmer55]

I have a question for you, seems you have a great understanding of how these alternators work. I have a Delco alternator on a sawmill. It went bad last summer. Replace it with a new one stopped working Within a few hours. I have repeated this process now with three different alternators. The sawmill had a lamp light on it but the previous owner replaced the lamp with an in-line fuse for whatever reason. If I put the lamp back in line like it’s supposed to be should my alternator work properly as it should? Did I do any damage to the alternator without running the lamp. And is there anything else I will have to do to the alternator after I hook up the lamp since I was not running the lamp?

[@shaundevine1030]

@@allischalmer55 Run the lamp and all will be well. The lamp gives and initial excitation of the field and once it starts to produce power it will be 2 positives to the lamp and will shut off. If the belt blows or the alternator stops producing power it becomes a ground again and tells you that it not producing power.

[@fredbloggs2417]

no stupid music all the way through and using a human voice spoken in clear English ' for a pair of hands video ' this was easy to watch and very helpful .

[@Swampwild1]

fred bloggs Exactly!

[@zyar46]

So, the voltage sensing wire, if you put a diode to "drop" the sensing voltage, example 12.8V from the battery to the toggle switch, and put two or 3 diodes in series, so that you get a drop of (1.2V) it will ramp up the voltage generation to 14V right, yet still seeing 12.8 on the toggled switch (exciter)

[@ThriftStoreHacker]

I'm not sure.

[@LIGHTOFTHEWORLD256]

Thank you For the video, but it's not practical, switching pin 2 on and off Will not stop /start charging, it will instead Toggle voltage regulation on and off , without pin2 the alternator still charge un regulated, secondly a diode Is needed in serries with the bulb.

[@MBFURUZ]

Seems like nobody is able to put a new alternator into their car , without aiming for the Nobel prize...

[@OFFDAMRKT-]

Thanks for the video! This was very helpful.

[@MyiMpakToLife]

Finally i found a good tutorial......

[@gulabkhan5360]

Very nice

[@stoneyswolf]

The second termanal for field can go straight to the main terminal that charges the battery. The sensing termanal goes to keyed power or a switch. You could just use a resistor if you wanted.

[@ThriftStoreHacker]

Retrogamer1010 great information. I'm currently looking for a side shaft engine to run the alternator up to a fast enough RPM to do some testing. Second hand market here in my town is ridiculous. May just get a new predator engine from harbor freight.

[@BottleFedCtsv]

You could use an old treadmill motor setup to test alternators up to speed

[@danieljames6752]

I am just trying to figure out how to connect the light bulb where does the positive and negative on the light bulb go

[@MechanicForGMCCars]

did ever some one tryed to use dual voltage regulators? or takeing off original delco 12si voltage regulator and used tractor regulator insted? I love to use capacitors as for litel more power in my car for hei ignition system. The problem that I face is expecialy hv ceramic capacitors cinde of change the starting charge or cutt in rpm range for alternator . So I hoppe for advice. Wuld cloosed loop voltage regulator help programabel unit or those so called avr units on generators? I also wuld like to know if dc generator voltage regulator culd by used on magnet alternator or some sort of amp cutt out selenoid ? That problem plagues my for years and Im anoyed at that shiti thing. I wuld like to have in case of emergency some sort of back up units for light bulbs or sending directly power to my ignition coil of course with resistor or resistor/capacitor box for experimental porpuse. I use vaporisators so thats why I need such unusual set up Im doing engine conversions . So thats why I have problem finding correct circuet for my baterry. Also there is problem with the starter motor as well so Im curriuse to know how can I give that thing more torque or over ride the voltage to it for easyr engine start up if posibel some one suggest starter motor booster circuet or baterry start up booster how that look like. Mostly I have problems starting engine in winter the coil does not get enough voltage so I used 4 pin relay insted but still the original hei does not suport retarding option so I was wondering as well if there exist circuets that can retard ignition timing it is E Core design ignition coil inductive trigger and 4 pin gm ignition module. If some one know devices that can do that mentioned effects please give some link to it.

[@albertano6969]

I have a 86 Buick Regal I switch my alternator bcuz it was bad now I have the oil choke light and battery on but once I step on brakes it goes off but I let go of brake pedal they come on again I also notice car off voltmeter is at 12.75 I turn on car remains the same once I gas it and battery light comes in it goes to 14.50 on voltmeter Any suggestions I replaced alternator twice already also I remove positive terminal and it shuts off

[@lukam20]

I have two questions. First are these wires strong enough for this since alternator has high amps (mine has 60amps and 12V). Second is this a way to excite your alternator? Because I've heard that all this wiring with the light bulb is simply because the alternator doesn`t start on its own so you have to excite it first. Oh and one more question. these connectors on the top (with the yellow thing) how do I know which one is which? On my alternator, it says L and B+.

[@ThriftStoreHacker]

I have not messed with this in a while so I cannot reliably recall the spec. The wires feeding the battery should be properly rated for the current. You will want to look up the exact version of alternator you have to verify what the leads do. I plan to revisit this in the next month because I finally found an engine to power the alternator. I will show how it is wired and a running demonstration.

[@throwbabys6867]

looks like a cluster charge from r6

[@fiddlerpin]

Why are you trying to reinvent the wheel?

[@jjyhgygjkuikkm]

Need a Ford altornator wiring

[@Kol-ingGaming]

can you use a test light instead of a bulb?

[@ThriftStoreHacker]

I'm not sure.

[@danwells7691]

1 and 2 isnt that field and stator and i think they 1 and 2 need to be switched

[@Swampwild1]

I think your right. 1 is the exciter and not dummy light. 2 is the field. One is normally connected to power on ignition. I’m watching this to wire my alternator dummy light.

[@RPM_Productions]

Would it still charge with no ground

[@ThriftStoreHacker]

You still need to ground the body of the alternator to the battery. I JUST purchased a 5hp Briggs engine at the antique store about 15min ago so I will be revisiting this project very soon.

[@niteflyer3380]

I picked up one of the same style alternators, did everything as described here but the thing is charging with no voltage going to the #2 connector on the alternator? the charge light never comes on with connections made but not turning and after letting it run for about 20 minutes or so I did notice that the charge voltage wants to creep up beyond the 14.50 volts... I think there might be something going on with the thing, glad I didn't pay a lot for it... what is your opinion?

[@ThriftStoreHacker]

Nite Flyer you could see 15/16v if the battery was really low but if it keeps climbing the regulator may be bad. As for the light, it only comes on if the battery is not charging (think battery light in your car). Test it with a fully charged car battery and see if results change

[@niteflyer3380]

the battery is brand new and shows me 13.15 volts before connecting to the alt, I am testing this on the bench. I have dummy light wired and the alternator is connected to the battery and spinning with the #2 wire disconnected, it is charging 14+volts with the #2 wire simply laying on the bench, maybe I'm missing the fact that there should be the key on factor? key on engine off the dummy light should be on correct?

[@ThriftStoreHacker]

Correct. key on engine off the light should be on. I don't think the dummy light needs to be connected.

[@niteflyer3380]

that's one thing that I am not seeing here. key on should be the dummy light if I have things right in my thoughts, 12vdc power to the #1 pin on the alternator, pin #2 is the exciter circuit which if in my head I have right should also come from the key on. I have disconnected both the #1 & #2 wires and the thing still throws out 14.+ volt to the battery. maybe my mind is a melt after tinkering with this for the better part of the afternoon but is it wrong to think that without the exciter circuit in tack there should not be any voltage from the charge to the battery? goodgreif... lol...

[@ThriftStoreHacker]

Nite Flyer oh ya. That's weird. If the 1 and 2 wires are disconnected it shouldn't be generating a field and it should definitely not be charging the battery. Sounds like something is shorting out in the internal regulator.

[@jmjavs5740]

Hi.. Will connecting the sense and lamp wires in reverse damage the internal regulator? Or can i just rewire it back to normal and wont cause damage?

[@ThriftStoreHacker]

John Marden Javier I'm not sure. I am currently making a new video with the alternator. Once I get it set up I will report back.

[@jmjavs5740]

Ok I will just wait for the video. Thank you so much for the response and for the very informative videos.

[@jmjavs5740]

Hi! I found the answer to my question. It shouldn't and it didn't cause any damage to the internal regulator.

[@ThriftStoreHacker]

John Marden Javier great! Good to know. I'm currently waiting on shipping of a small engine to do the alternator video. Going to make a 12v portable battery charger.

[@ibrahimwrites]

Hello can you please tell me how to bypass alternator indicator light? Thanks

[@ThriftStoreHacker]

RealTech 9ja I don't think it needs to be hooked up. I will have to test this.

[@ibrahimwrites]

ThriftStore Hacker please do...am looking to use the regulator car 3wire alternator to charge batteries but the indicator light being on will drain the batteries again. Thanks

[@ytubeerr]

RealTech 9ja no need to bypass it if you don't want to run an idiot light just leave it disconnected,

[@drummerjay802]

I thought you had to to teporarily excite the exciter wire

[@alangeorge9354]

The indicator light is what turns the alternator on and makes it charge... when there's a positive voltage on both sides of the light bulb it won't be on. That's why the battery light in your vehicle shuts off when your engine starts. When the alternator goes bad there's not a positive voltage on the alternator side of the light bulb so it shows 0 volts and the light turns on. If the bulb isn't hooked up it won't charge. If the wire is ran direct it will always energize the alternator even when it's not running and will drain the battery. (If wired up to battery source circuit i.e. in a car)

[@vijaypatel-tr5ee]

No test ,😩

[@ThriftStoreHacker]

I am working with this alternator for the next 2 videos. You will see it in operation and how to set it up.

[@leopoldpoppenberger8692]

to much fluff

[@tissaeakanayake161]

thie alternator 500 years ago.it,s too old one man