12 Volt Conversion Done- One problem

[terryjd]

Well I decided to switch my SC to 12 volt. Seems to work well except for one little problem. When the tractor is running that light in the new system,just the element in the bulb stays red, about like what an electric heater element looks like, doesn't go out compleatly.
Tractor shut off, light is out. Turn tractor lights on amp meter goes to about 10 amp discharge. pull start switch out that system light comes on bright, amp meter drops about 3 amps. Start tractor system light dims, amp hand goes to about 20 amp then starts to drop back to about 15 amps. Open tractor up amp guage jumps to 20 amp and then drops back to 10 amps and stays there. Turn Lights on drops back to 8 amps. The system light element just glows a bit. Shut tractor off system light flickers bright till motor stops then goes out.
Anybody have any idea why the system light has just that bit of glow to it? Everything else seems to work right and does what it is suppose to when it is suppose to. A ground not good enough somewhere, alt not working right, I screwed something up in the wiring?
Thanks for any ideas
Terry

 

[Bob]

You've either got a poor ground, or a high resistance connection somewhere between the alternator's output stud, the ammeter, and the battery post. Check the voltage at each of those points. Does it vary significantly from on test point to another?

(If you used a 12-Volt generator, the above still applies.)


If all that checks out, the alternator may have a bad diode in it's bridge rectifier or diode trio.

 

[Janicholson]

From your description, it seems to be working fine. The light feeds ignition voltage to the regulator in the alternator when energizing it to begin charging on startup (looks like a path to ground to the light). When started, the regulator sends charging voltage back to that side of the bulb, effectively causing it to go out (12v on both sides of the bulb, no ground, no light). Because yours is lit like a glow worm, (as Bob points out, there is a difference in the voltage at the bulb. This is possibly due to smaller wires than best suited going to the battery from the alternator (#10 needed), or higher than normal resistance in a connection to the ignition, or the wires to the ignition. Clean and shiny wires with a touch of silicone to protect after cleaning and attaching might help. I will add that if it is not discharging the battery between times that you operate it, and the lights stay bright, and all seems to check out, ignore it. JimN