alternator field wire size

Posted By: Stroker

alternator field wire size - 03/01/13 04:20 AM

What ga. wire is used on 72 era B bodies for the field wires?
Would it be beneficial to use a slightly bigger wire on a 75 amp alt, or are they just for sensing?

Posted By: Cab_Burge

Re: alternator field wire size - 03/01/13 04:52 AM

I don't have a 1972 FSM but I'm alomst sure the pre 1971 and earliers cars used either a 16 or 14 gauge field wires

I don't know what you call a sense wire, the early mechanical alternators fed the feild side of the alternators off of the distributor ballast resitor, the later cars with electronic voltage regulators use one wire from the ignition switch and the other one from the ignition circiut off of the ignition ballat resitor

Posted By: 1_WILD_RT

Re: alternator field wire size - 03/01/13 05:33 AM

Sensing is done by the voltage regulator which is not internal on vintage Mopars.. But the field wire is a low current circuit & 16 ga is what was originally used... The Battery wire however carries the load & should be larger...

Posted By: 71_deputy

Re: alternator field wire size - 03/01/13 03:10 PM

correct above as field shouldn't be more than 3 amps total!

Posted By: Stroker

Re: alternator field wire size - 03/01/13 08:09 PM

So what's the consensus?
14? 16?
If I didn't have MSD ignition, etc, etc, I'd just have an Evans harness made.
But-I'd have to hack it all up to get my other stuff wired.
I wonder if they could do a bulkhead to regulator plug with field wires...
I just want to drive the car this year.
It's been off the road too long.

Posted By: John_Kunkel

Re: alternator field wire size - 03/01/13 08:42 PM

18 ga is all you need. Even newer vehicles with 140 amp alternators only use 18 ga for the field wires.

Posted By: NachoRT74

Re: alternator field wire size - 03/01/13 11:43 PM

18ga was used from factory

Posted By: Stroker

Re: alternator field wire size - 03/02/13 03:47 AM

Thanks, guys.
And by "sensing," isn't this what they basically do?
Sense voltage to tell the alt what to do?
Electricity=voodoo
;-)

Posted By: 1_WILD_RT

Re: alternator field wire size - 03/02/13 04:09 AM

Quote:

Thanks, guys.
And by "sensing," isn't this what they basically do?
Sense voltage to tell the alt what to do?
Electricity=voodoo
;-) [/quote

Yes which as I pointed out earlier is done by the voltage regulator...

Posted By: b1dartsport

Re: alternator field wire size - 03/02/13 05:31 AM

I have a 150 Amp Powermaster Denso that is internally regulated and the sensing wires for it on the plug are 18 gauge.

Posted By: John_Kunkel

Re: alternator field wire size - 03/02/13 11:04 PM

Quote:

Thanks, guys.
And by "sensing," isn't this what they basically do?
Sense voltage to tell the alt what to do?
Electricity=voodoo
;-)

There is current flowing through the field wires, the "sensing" is done by the regulator via the blue IGN1 wire.

Posted By: NachoRT74

Re: alternator field wire size - 03/03/13 03:04 PM

is not a SENSING wires, its a FIELD SOURCE wire

these wires feed both poles to the rotor coil and when spining creates the magnetic field what outer stator captures.

Posted By: Stroker

Re: alternator field wire size - 03/28/13 02:54 PM

"The sense is sensin' that the juice keeps pumpin' and I know why..."
-Keith Richards, 1981.
Really, isn't it all just semantics?
Is the large wire on the alternator for charging?
NO! The alternator charges.
Etc, ad nauseum.

Posted By: NachoRT74

Re: alternator field wire size - 03/28/13 08:48 PM

not really semantic. The GM speelling is what give us the "SENSING" therm, where actually switches on the regulator and gives the signal to cluster light. Beside the "sensing" wire on GM, they get the SOURCE wire for reg/rotor in a diff wire

the field wires on Mopars actually FEED the alt rotor to be able to produce the output power. No sensing at all

Is not just semantics, is a diff way to work.

Posted By: denfireguy

Re: alternator field wire size - 03/28/13 09:12 PM

Quote:

not really semantic. The GM speelling is what give us the "SENSING" therm, where actually switches on the regulator and gives the signal to cluster light. Beside the "sensing" wire on GM, they get the SOURCE wire for reg/rotor in a diff wire

the field wires on Mopars actually FEED the alt rotor to be able to produce the output power. No sensing at all

Is not just semantics, is a diff way to work.

The sense wire on the GM was an output to let the idiot light know when to turn on. The field wires on Mopars regulate the output on the big wire by varying the voltage on the field. That was done internally on the GM alternators and because of the heat were a frequent source of failure.

Posted By: 383man

Re: alternator field wire size - 03/28/13 09:24 PM

There is current flowing through the field wires, the "sensing" is done by the regulator via the blue IGN1 wire.

This is correct. All voltage reg need to know battery voltage and it dont matter if its internal or an external reg. They all need a 12 volt sense wire so the reg can control the alt output by the field circuit. And as was said the blue ign1 wire at the voltage reg is where the Mopar electronic reg picks up battery voltage. The other wire on the reg is the field ground wire as it uses that to control alt output. The ign1 wire also feeds the battery side of the ballast res and the factory ign module. Ron

Posted By: NachoRT74

Re: alternator field wire size - 03/28/13 09:37 PM

Quote:

Quote:

Thanks, guys.
And by "sensing," isn't this what they basically do?
Sense voltage to tell the alt what to do?
Electricity=voodoo
;-)

There is current flowing through the field wires, the "sensing" is done by the regulator via the blue IGN1 wire.

DEPENDING on year setup

on electronic systems that's it. the blue wire section going to reg is the sensing one to make work the regulator and FEED NEGATIVE, sourced by chassis, but not the blue one going to fields... both shares same source but for diff purpouses

on mechanical systems, this blue wire senses ( allong with chassis ground ) AND feeds at the same time to get same kind of positive signal on reg output