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Installation of alternator in 54 Chevy 3100

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put-put

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Shop installed an alternator in place of generator in order to support Vintage air system. B+ is wired to battery and horn relay. Unit is putting out 12.2 V at all rpm, so the battery is not staying charged. Also installed a push fan in front of a/c coil and radiator because the 5 blade original did not keep the temp down. How should the unit be wired to operate properly? I have the 3 post regulator.
 
You should disconnect or remove the old regulator . alternator needs unfused battery current to the + terminal at all times , even with key off .

_Some_ alternators need another lead from the ignition circuit to exite the field windings and make it charge @ idle speeds .

Asking for a Delco " SI " typ alternator @ your FLAPS will negate the needs for the secondary wire .

There should be much written on this in the archives including schematics and diodes needed for some setups , not all .

Fan should have a relay that's wired live and has a temp switch in either the upper tank of the radiator or the thermostat housing , I got a thermostat housing from a 80's vintage Camaro as it has a bung in it ofr the fan switch so it'll switch on after I shut the truck off and it begins to heat soak , runs 5 ~ 10 minutes depending on the heat .

If you have a pusher fan , delete the stock fan , don't need both , pusher fan _must_ be wired to stay on anytime the AC clutch is engauged .

Stock radiator is way overkill for any V-ate so if still running too hot , have it " rodded out " flushing is a wa$te of time and $ in every case .
 
O.K. , I wasn't sure what engine .

What are you using for the alternator bracket ? 1962 (only) 235's came with Delcotron alternators so if junkyards near you that'll be the best thing .

I just used my old generator bracket , gave a it a 180° turn and had to drill one new hole in it then I got a long bolt and a stack of flat washers to shim the alternator from sliding up & down the bolt , a cleaner way is to cut a piece of pipe to make a shim but I'm a farm mechanic and the washers were handy , free and faster than hunting up a bit of pipe .
 
Nate,
i have Vintage Air bracket for alternator, so that's an easy solution. The alternator does not have an internal regulator. The old mechanical regulator is wired using only 3 of the 4 post. The shop wired the B+ on the alternator directly to the battery and to the regulator B+. I'm not certain that this is the right thing to do for this case.
Also, the amp and fuel gauges are not working. This maybe because of the wiring. I had them rebuild by Absolute and converted to 12 V.
thanks!
 
O.K. , sounds like the wiring is O.K. ., using the B+ regulator post is fine .

Maybe this alternator needs an exciter wire , many do .

My current alternator is from a....oh hell I dunno , '82 Camaro or summat , it's a 35 amp. unit and wasn't charging @ idle speeds untill I discoverd the DPO had used _three_ smaller diodes in lieu of one proper one... replaced that with the correct one from Radio Shack (about $2.00) and all is well now .

I just found a SI typ new in the NAPA box and will post up that part number to-morrow when I'm back at the shop . 'K ? this one need no exciter wire and charges 100 amps too . I have no AC nor other silly stuff so I figure I don't need a mondo alternator .
 
SI Alternator Part # @ NAPA

O.K. , this is the one if you want to have super bright lights and plenty of juice for your stereo , power windows amps and what all else

NAPA # 66135 in thier Pro Series line of rebuilt alternators .

You'll need to swap your old 3/8" pulley onto it but that is a simple thing .
 
Nate,
i found that the wires from the alternator to the regulator were crossed. the Field and Armator wires were crossed. i checked with a local mechanic re the wiring and he told me that the 4th tab on the regulator should be hot at all times, as you said. He told me that after cranking the voltage on the 4th tab should go to zero. After i corrected the wires, i tried it and it says at 12V. the alternator does charge up to 15.6 V under load now.

thanks for the help.

Put-Put
 
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