Alternator plug ins

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Dizzydean

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After finishing my HEI conversion I started the alternator upgrade to the 70's type and the electronic voltage regulator. Ive used a factory plug from the regulator to the alt. but I'm unsure where to plug the ends into as the original had only one field spade. I see one is in a ceramic type housing the other not and both
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say field. Appreciate any guidance with this.
 
The connectors at the alternator can go on either post. What is not clear to me is how you wired the rest of it. the blues tie together and go to your switched "ignition run." This is IMPORTANT to check that you don't have voltage drop which causes the system to OVER charge. The VR MUST have an excellent ground "same as" negative battery
 
thanks 67. I haven't wired anything else up yet. the wires in the first pic are the old vr wires I just moved them out of the way. I'm going to try to plug the blues together at the regulator and I did sand off the paint behind for a good ground.
 
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The earlier 'single field' systems basically use a regulator that supplies a single pulsed 12 volt pulsed signal to the alternator field plug (the other end of the field winding is internally grounded in the alternator).
The factory electronic style is to be used with an alternator with a 'floating field' (it is not internally grounded). This style basically supplies a constant 12 volt to one field winding (blue wire) and will pulse the ground to the other field winding (this is why the regulator must have a good ground). The reason for the floating field design has to do with the electronics in the regulator. One thing you need to make absolutely certain is that neither one of the field connectors is grounded to the alternator case. If one is, you will melt some wires.
Removing the insulators to one of the field terminals on the alternator is a common way to use the later style 'dual field' alternators with the earlier single field style regulator setup.
If nothing is grounded at the alternator, just splice the original blue wire to the blue wire at the electronic regulator and you are golden.
 
Badvert65 said:
........One thing you need to make absolutely certain is that neither one of the field connectors is grounded to the alternator case. .
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This is absolutely correct and happens quite often. Sloppy rebuilders, broken or incorrect field brush holders/ hardware/ insulators, etc.
 
Well just to be sure I will run a ground wire from the case to another ground. So by looking at the pics does it appear that the either connection is grounded? I was wondering on the one being encased in a housing and the other not. Thanks again for the help. Ill wire everything but not going to start until I see a reply from you guys.
 
Use a meter or test light to check for a ground. Don't connect until you are sure there are no grounds. If memory serves, one of the fields is in a plastic thingie and the other just has plastic washer/spacer insulators (top and bottom).
 
Don't trust "looking". Use a meter. Neither field connection should show continuity to ground. A separate ground wire on those is not necessary. You DO want the main battery cable grounded to the block, and the alternator is "by bolt"
 
:BangHead: Wow I went from mission accomplished to epic failure in about 2 minutes. Short version: alt fields good, wiring to vr plug and firewall after tap good, no shorts no alt grounding. Fired up finally and gauge showed charge but my volt meter showed a hard 14 volts like it was pegged. Had to give throttle to get engine warm and charge was high then engine quit and everything shut off. My plug in fuse(25a) protecting the fusible link blew. Replaced it engine turns but wont start now. Also alt gauge barley drops to discharge now very minute and when I crank volt meter drops to almost nothing. So engine cranks but wont fire. Did the module fry also? I have a 25a fuse protecting it and its still good. Done for a couple days I have a lot of backyard items to tend to but if there's things I can meter check I will as time permits.
 
Dizzydean said:
and gauge showed charge but my volt meter showed a hard 14 volts like it was pegged. .
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gauge? You mean the ammeter? Was it pegging?

"Hard?" this is an in car permanent analog meter?

Sorry but you SHOULD have checked at the battery with a multimeter. You likely would have found that it was way way way over voltage, and you should have shut it down.
 
Dizzydean said:
My plug in fuse(25a) protecting the fusible link blew..
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I don't know what you mean, here..........did you add a 25A in series with the link? That is no where near enough. all the current from the alternator goes through that link, as high as the alternator charges
 
Your car has no voltmeter from the factory. A 25 A fuse should have protected the factory dash ammeter (~50 A range or so). Sounds like no major damage. If you still have spark, it may have just flooded with gas.
 
This is the thing, a 14 volt reading is so 'normal' as to not be worth mentioning. If you put a voltmeter across the battery, or at the output terminal of the alternator, you can rev the motor. Watch the voltage, it should remain around the 14 volt (+/- 1 volt) level, If it shoots above 15 volts and rises with the RPM, your regulator is definitely bad (or you have a short somewhere). A typical alternator is capable of putting out over 25 volts. Just for a frame of reference, 13.8 is the ideal, perfect voltage level. 12 volt or less, the alternator is not working at all. Over 16+ volts (ball park) and the alternator is working overtime (bad regulator or shorted wire). An overvolt condition will eventually fry any electronic circuits and likely blow out some light bulbs. It could even set the wire harness on fire (seriously). I am just warning you to be cautious. Overvolts is bad, very bad. Undervolts is not good but will typically just give you a dead battery.
If you are not sure what is going on, get professional help with it. Do not take chances (unless you are well insured).
 
Should of posted this earlier to maybe help someone. So to keep my factory wiring and not cut and splice to make things fit I found an extra factory elect VR plug. It was to short so I lengthened as needed. Short (pun) story I plugged the new blue and my old green. Didn't even see the new color wire sitting there just missed it completely. The VR end of my old greenie was up against the firewall and was the cause of my electrical dilemma. I pulled them away and taped them up, replaced the ign module and the VR, car runs great. Doesn't pay to rush things.
 
Badvert65 said:
......... If it shoots above 15 volts and rises with the RPM, your regulator is definitely bad (or you have a short somewhere). A typical alternator is capable of putting out over 25 volts.
Click to expand...

Your post was pretty good thinking except the above.........

There are several things that can cause over voltage without being the VR or a short. "Wiring problem" might be a better word. So far as an alternator maximum voltage "I'LL SAY" more than 25!! LOL. "Back in the day" you could buy these stupid switch boxes which disconnected the alternator from the battery and rounded the output to a 120V receptacle, giving you "120V DC" for accessories.
 
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