The Stovebolt Site Forums The Shop Area The Electrical Bay Alternater ?

I was reading earlier about wiring up a alternater.They had a GM with the plug for the exciter. They had run the exciter wire to the batt lug on the alternater. this way the batt fed the exciter and then the alternater charged. Basicly made a one wire alternater.Will this work? Will the higher voltage to the exciter cause the alternater to fail sooner? just a thought, wont rewire my motor till i hear some thoughts... If it works I can use the feed off the starter to go to the dist side of the coil for starting.

I've wired them that way for over 30 years with no failures. If you look at original-equipment wiring diagrams, they've got full battery voltage there on most of the systems anyway. The other connector is only needed if you plan to run an idiot light.
Jerry

HRL answered your alt. Q. although Ive never run one like that.
In regards to the bypass feed, you cant run from the starter to the dist. side of the coil. I dont know what ign. system you are useing but if you have a stock 59 system the bypass goes from the R term on the starter to the pos. side of the coil.

Yes Thats what I ment to say. From the starter to the coil side of the ballast resister. I was hoping to get it started a little quicker. Thanks for the info.

You can wire an alternator that way and it will work...but it is kind of missing the point. The purpose of the exciter wire is to excite the fields inside of the alternator when you turn the key on so the alternator will begin producing current as soon as the engine is running. It is indeed better to connect the exciter wire to the ignition or (+) side of the coil or the coil terminal on the ignition switch. You will have a slight but constant electrical draw if you connect the exciter wire to the battery instead. If you drive your truck everyday you can get by. Keep in mind that if you are replacing a generator with an alternator and you do not have the more modern accessory type ignition switch that the engine may keep running after you turn the key off because the alternator is still producing current at idle whereas the generator did not. The fix is a DA Plug which will make everything work as it did before. and you will live happily ever after....

On every factory wiring diagram I've been able to find, the #2 connector on the perimeter of the 10SI alternator housing gets unswitched battery voltage. The #1 terminal (called the 'exciter' by some) is used as a ground for an idiot light. It might also kick in the charge a little quicker, but in my experience it's absolutely unnecessary for proper voltage regulation. Your mileage may vary!
Jerry

Thanks for the updates. I am also trying to get a old tractor running and it has idiot lites for gen and oil. and was converted to alternater also. i have had the same batt in this truck for 10 years and its still doing well . I thought if I ran a wire to the coil it would start quicker. I have a volt guage in the dash so I can see it charge.

If you're running a coil with a ballast resistor between the ignition switch and the coil, the normal running voltage at the coil + terminal will be around 9.5 volts. A bypass wire from the starter solenoid "R" terminal to the downstream side of the resistor or the coil + terminal is a good idea so the coil gets full battery voltage during cranking. That circuit has nothing whatsoever to do with the operation of the alternator, however.
Jerry