No announcement yet.

Bad generator?

  • Filter
  • Time
  • Show
Clear All
new posts

  • Electrical: Bad generator?

    I've not owned. 6 volt system before with a generator and not an alternator. Shouldn't this gauge (Yes it works)read SOMEWHERE on the positive side if the generator is working? This is the gauge as I'm going down the road. Need a new one?
    Attached Files

  • #2
    If your battery is fully charged and your idling it will just hover past the 0 like it showes on the gauge.


    • #3
      Jwitt, so I had just installed a new battery when I took this pic. I have had to jump-start the car numerous times. The previous battery was only around a year will this gauge read if the generator isn't charging the battery? In the negative?


      • #4
        If your battery is fully charged and your idling it will just hover past the 0 like it showes on the gauge. As long as it doesn't go into the - side its fine


        • #5
          Turn on the Headlights and you will find out.
          Discharge when not running, Lights ON and a Charge for a couple Minutes after Starting to charge it back up.

          If it does not Charge, it could be as simple as it needs to Have the Regulator Polarized.
          We would need to know if it is a Champion with an Autolite System or a Commander with a Delco System, to know the correct way to do that.
          Last edited by StudeRich; 04-16-2021, 04:29 PM.
          Second Generation Stude Driver,
          Proud '54 Starliner Owner


          • #6
            I'm sure I'll get some comments from others but if I really want to know if my charging system is functioning I will pull the + side cable loos from the battery while its running. If the car dies the generator or voltage regulator is suspect. If it stays running everything is fine.


            • #7
              So studerich, lemme make sure I off turn on the lights for a bit. Turn car on and the gauge should go to the + side for a bit to show the generator is actually charging the battery?
              48 Champion by the way


              • #8
                ^ Yes. Bring the engine above idle after you start it following this test, and the ammeter will swing toward "charge" if the generator is charging.

                It takes a bit to get used to how an ammeter reads. The biggest thing to remember is that it only tells you if the battery is being charged or discharged... if you've had to jump start the car due to a dead battery, it should read on the charge side for quite awhile as you're driving, then taper off closer to zero once the battery is fully charged. If the needle doesn't move at all (toward discharge) when the lights are on and engine is off; then either someone bypassed the ammeter, you've got wiring problems, or the ammeter is burned up.
                Whirling dervish of misinformation.


                • #9
                  First things first. Is the battery installed correctly? Six volt Studebakers were all positive ground. If the battery was installed backwards, the car might start and run, but the generator won't charge. So, look under the hood. Is the positive battery post connected to the ground cable or strap? Positive posts on top post batteries are a little larger in diameter than are the negative posts. Not much difference, but readily seen if you look for it. Naturally, the cables won't fit right on a wrongly-installed battery, but it's possible to make them fit. So make certain the battery is installed properly. So few shops anymore have techs that worked on thse old cars when they were commonplace, that such errors are prevalent now.

                  So, assuming the battery is now installed properly as positive ground, now turn on the headlights, without starting the car, and see if the ammeter deflects at all. It should go to about -10. That's a ten amp discharge. If it goes to +10, then the ammeter is hooked up backwards, which is probably an indication that somebody tried to convert the car to negative ground in the past. If that happens, I would suggest you check with your local chapter, and find a competent Studebaker mechanic to make it right again.

                  Moving on, let's assume that headlights on did give a -10 deflection on the ammeter, so your battery and ammeter are wired correctly, as far as we know. Turn the headlights off, and start the engine. Slowly bring the engine RPM's up to what sounds like a normal road speed. At some point, you should see the ammeter needle kick to the right (+) and flutter a bit. From there on, it will slightly mirror engine speed; reading about zero at idle, and rising close to 35 amps at high engine revs. It should limit out at a little less than 35 amps, if the voltage regulator is working properly, and further increase in engine speed won't make it charge any more. If the ammeter fails to indicate any charge at all after the engine has been started, and RPM's increased, then you have either a bad generator, bad regulator, or the generator needs to be polarized. People talk about "polarizing the regulator" but what is really getting polarized is the field pole set in the generator. The field coils are wound around soft iron pole pieces, and these pole pieces retain a small amount of residual magnetism. It's not very much, but it's enough to allow the generator to put out a little bit of current without being excited by a battery. That small current is enough to close the cutout relay in the regulator, which then sends battery voltage to the field, and juice up the magnetism so that generator can produce its rated output. If the residual magnetism in the pole pieces is zero, or in the wrong polarity, the generator simply won't put out at all.

                  Now, the official correct way to polarize the generator is to look up the make and type of generator, and determine if it is "A circuit" or "B circuit", and then polarize accordingly, but guess what? It all boils down to either grounding the field terminal for fraction of a second, or connecting it to the "hot" side (negative in our case) of the battery for a fraction of a second. The wiring in these old six-volt cars is very robust, and you won't hurt anything, even if you make a momentary dead short with a skinny wire clip lead. The clip lead will melt before the car's wiring does. And we are definitely talking momentary contact here: just brush the clip of the clip lead against the "F" stud for a quarter-second or so. If you see a small spark, you probably accomplished the polarization, but even if you didn't, check by starting the car and see if the generator puts out. If it doesn't, try polarizing the other way from your initial try, and see if that works. If that doesn't work, go through the routine again with the engine running. Remember, only attempt to polarize the "F" (field) stud on the generator. Leave the "A" stud (armature) strictly alone. They are normally marked "A" and "F", and the "A" stud is usually larger, may have a larger nut, and a fatter wire on it. It has to handle 35 amps, after all. You could call this the "trial and error" method of polarizing a generator, but it should eventually work, IF all that is wrong is that the generator needs to be polarized, owing to having been wrongly polarized in the past. If either the generator or regulator is faulty, or plain worn out, no amount of polarizing is going to fix it.

                  Sorry for the wall of text, but it's really easy to do all this, a lot easier than typing it all out, I can tell you. Anyone wants to challenge this, or add to it, great.
                  Gord Richmond, within Weasel range of the Alberta Badlands


                  • #10
                    Thanks Gordr!


                    • #11
                      Well done Gordon.
                      Dwc - Is your fuel gauge working? If so, you should add gasoline to the tank. Was/is the battery hooked up properly (positive ground)?
                      Gary L.
                      Wappinger, NY

                      SDC member since 1968
                      Studebaker enthusiast much longer


                      • #12
                        Excellent post, Gord!

                        One polarizes the generator field coils at the regulator because it is 1. easier, as a short wire can be used 2. safer, as no sparks are created at the battery terminals. And henceforth people call it polarizing the regulator. Note, regulators are made in one polarity and typically can not be changed later. They do not loose magnetism, as they don't hold any.
                        Frank DuVal

                        50 Commander 4 door