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Alternator Upgrade Related Questions (was One-Wire Alternator Questions)


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I'm still trying to digest all of this so bare with me.

It sounds like I can feed the electric choke from a 3G alternator. It also sounds like I can connect it up to the starter relay (with a megafuse) the same way I would a one-wire alternator. That leaves the entire harness out of the picture and makes it removable, right?

I still have to deal with the ammeter-to-volt meter conversion. I actually have two functioning ammeters and I am shipping one off today for the RCC conversion.

My existing wiring is all in bad shape, so losing that entire harness would be a benefit for me. I also have no plans of going back to a 1G or 2G. However, having an alternator that I can easily swap or work on, is a plus.

I'm in no hurry and happy to answer questions.

Yes, you can power the choke off a 3G since it has a stator connection just like the 1 & 2G.

As for removing the whole harness, yes you can. But you'll then have to do some wiring. Let me do some more work to explain that in another post.

 

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I think I need more information about the last line of your reply. Useless at idle and low rpm? Since this is a work-in-progress truck, and since I live in a high-traffic area, the truck tends to idle a lot. Can you tell me more about what you mean?

1-wire alternators have to be self exciting, because there is no key on power going to the field.

This means they can't energize the windings until the unit is spinning and that there is a threshold rpm to produce any output, and that output is somewhat proportional to rpm.

Now, once spun up they can be wound to put out a good amount of power.

But remember that regardless of stated Max power they will only provide what's needed to keep the trucks electrical system at the set point (usually 14.3-14.5V)

A 1, 2 or 3G alternator has a sense wire (y/w)

A stator wire (w/b)... also used for choke, or in the case of a 351H.O. to trip a choke relay

An exciter wire (lg/r) that provides key on power to kickstart the alternator output.... rather than relying on it to bootstrap itself.

An output wire or* cable, usually bk/or

 

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1-wire alternators have to be self exciting, because there is no key on power going to the field.

This means they can't energize the windings until the unit is spinning and that there is a threshold rpm to produce any output, and that output is somewhat proportional to rpm.

Now, once spun up they can be wound to put out a good amount of power.

But remember that regardless of stated Max power they will only provide what's needed to keep the trucks electrical system at the set point (usually 14.3-14.5V)

A 1, 2 or 3G alternator has a sense wire (y/w)

A stator wire (w/b)... also used for choke, or in the case of a 351H.O. to trip a choke relay

An exciter wire (lg/r) that provides key on power to kickstart the alternator output.... rather than relying on it to bootstrap itself.

An output wire or* cable, usually bk/or

Ok, let's try this. Here are three schematics in a fairly quick and dirty fashion. Obviously the next step would be to add the voltmeter and the associated key-on relay, but let's hold off on it for a bit.

Does this help?

1: The original schematic straight from the EVTM

2: The EVTM schematic without C610 and its associated wiring that you can remove

3: The EVTM schematic with a 3G added and how to connect it, but w/o the voltmeter

1985-etm-page17.thumb.jpg.daacbe3bfc2284d6100ef808ef513a90.jpg

Page_17_without_C610__Its_Harness.thumb.jpg.6d3bb737d275ab48c7ae7a18d33a0c35.jpg

Page_17_with_3G__Wiring_But_Not_Voltmeter.thumb.jpg.7080b5b3999de232ea705e4454c86789.jpg

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Ok, let's try this. Here are three schematics in a fairly quick and dirty fashion. Obviously the next step would be to add the voltmeter and the associated key-on relay, but let's hold off on it for a bit.

Does this help?

1: The original schematic straight from the EVTM

2: The EVTM schematic without C610 and its associated wiring that you can remove

3: The EVTM schematic with a 3G added and how to connect it, but w/o the voltmeter

Looks good!

Thank you for adding the Megafuse. :nabble_anim_handshake:

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Looks good!

Thank you for adding the Megafuse. :nabble_anim_handshake:

Having slept on it, I think the megafuse needs to move up in the drawing so one of its lugs can be used as the terminal for the Y wire and the wire going to the starter relay. Just to make things as easy as is possible.

And, I should redraw the wires so they have some color. That way we can refer to "the red wire" or the "yellow wire".

Just things to fine tune as we revise the approaches, plural, to 3G conversions.

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Having slept on it, I think the megafuse needs to move up in the drawing so one of its lugs can be used as the terminal for the Y wire and the wire going to the starter relay. Just to make things as easy as is possible.

And, I should redraw the wires so they have some color. That way we can refer to "the red wire" or the "yellow wire".

Just things to fine tune as we revise the approaches, plural, to 3G conversions.

I might eliminate "130A"..

ETA: I would simply put "appropriate Megafuse" as well.

Most people don't need the big alternator in these trucks.

They got by for the entire production life with 40 or 60A

There are plenty of people who would just like a nice 95A, 135mm case 3G just for simpler wiring and low RPM delivery.

The small case 95 fits better on these trucks.

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I might eliminate "130A"..

ETA: I would simply put "appropriate Megafuse" as well.

Most people don't need the big alternator in these trucks.

They got by for the entire production life with 40 or 60A

There are plenty of people who would just like a nice 95A, 135mm case 3G just for simpler wiring and low RPM delivery.

The small case 95 fits better on these trucks.

Good point. And also eliminate the "150A" on the megafuse. Or maybe make that "Sized in accordance to the alternator output"?

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Good point. And also eliminate the "150A" on the megafuse. Or maybe make that "Sized in accordance to the alternator output"?

this sure is starting to look easy on paper. I really like that you are taking the time on this. such a valuable option. I do wiring a lot yet I still struggle with explaining something like electricity that cannot be seen until it's too late. never an engineer but many years servicing in the field and everyone's thought process can be a little different.

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Ok, let's try this. Here are three schematics in a fairly quick and dirty fashion. Obviously the next step would be to add the voltmeter and the associated key-on relay, but let's hold off on it for a bit.

Does this help?

1: The original schematic straight from the EVTM

2: The EVTM schematic without C610 and its associated wiring that you can remove

3: The EVTM schematic with a 3G added and how to connect it, but w/o the voltmeter

Having all three of these in one place does make it a lot easier to understand what is going on. I agree that having the actual colors marked on the schematic would help. It definitely looks easier on paper but in my case that could just be due to the rats nest of a mess I have under the hood.

I appreciate all of the work you all are doing on this and I know the community does as well.

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