From: xenolith@optusnet.com.au   
      
   On 13/5/2023 8:39 pm, 😎 Mighty Wannabe ✅ wrote:   
   > On 5/13/2023 5:33 AM, Xeno wrote:   
   >> On 12/5/2023 1:37 pm, 😎 Mighty Wannabe ✅ wrote:   
   >>> On 5/11/2023 11:11 PM, Snag wrote:   
   >>>> On 5/11/2023 9:49 PM, 😎 Mighty Wannabe ✅ wrote:   
   >>>>> On 5/11/2023 8:47 PM, Snag wrote:   
   >>>>>> On 5/10/2023 7:33 PM, 😎 Mighty Wannabe ✅ wrote:   
   >>>>>>> On 5/10/2023 9:39 AM, 😎 Mighty Wannabe ✅ wrote:   
   >>>>>>>> On 5/10/2023 12:55 AM, Xeno wrote:   
   >>>>>>>>> On 10/5/2023 3:05 am, 😎 Mighty Wannabe ✅ wrote:   
   >>>>>>>>>> On 5/9/2023 10:39 AM, Xeno wrote:   
   >>>>>>>>>>> On 9/5/2023 11:34 pm, 😎 Mighty Wannabe ✅ wrote:   
   >>>>>>>>>>>> On 5/8/2023 11:58 PM, Ivan Vegvary wrote:   
   >>>>>>>>>>>>> 1948 Pontiac, 12V battery, one wire alternator (was working   
   >>>>>>>>>>>>> when parked 12 years ago).   
   >>>>>>>>>>>>> No amperage reading even at 2000 rpm. Battery voltage   
   >>>>>>>>>>>>> 12.6V. Battery voltage with car running 13.8V, however amp   
   >>>>>>>>>>>>> meter only reads 0 or negative with headlights on. Placed   
   >>>>>>>>>>>>> an after market ammeter between the alternator and the   
   >>>>>>>>>>>>> battery.  Same reading as ammeter in the dash.   
   >>>>>>>>>>>>> How could this be?  Alternator supplies voltage but no   
   >>>>>>>>>>>>> current.   
   >>>>>>>>>>>>> After idle for 12 years maybe residual magnetism is gone.   
   >>>>>>>>>>>>> Needs to be excited. Can't find a YouTube that shows me   
   >>>>>>>>>>>>> which terminals to zap.   
   >>>>>>>>>>>>> All help is appreciated.  I can certainly buy a new unit,   
   >>>>>>>>>>>>> but possibly have other problems.   
   >>>>>>>>>>>>>   
   >>>>>>>>>>>>> Thank you   
   >>>>>>>>>>>>   
   >>>>>>>>>>>> If you get 13.8V when the car is running, that means the   
   >>>>>>>>>>>> alternator is providing output.   
   >>>>>>>>>>>>   
   >>>>>>>>>>>> The alternator output is AC. You need to use AC ammeter to   
   >>>>>>>>>>>> measure the AC current output from the alternator.   
   >>>>>>>>>>>>   
   >>>>>>>>>>> Correction, the alternator output is DC. The 6 internal power   
   >>>>>>>>>>> diodes provide the necessary rectification. The 3 exciter   
   >>>>>>>>>>> diodes are meant to excite the field coils and set the   
   >>>>>>>>>>> generation process into gear.   
   >>>>>>>>>>>   
   >>>>>>>>>>   
   >>>>>>>>>>   
   >>>>>>>>>> Are you sure that's true for 1948 Pontiac?   
   >>>>>>>>>>   
   >>>>>>>>>> Maybe that alternator had been modified to use external   
   >>>>>>>>>> rectifiers and regulator.   
   >>>>>>>>>>   
   >>>>>>>>> Then it wouldn't be a single wire alternator, would it? Think   
   >>>>>>>>> about that for a moment. Alternators are, typically, 3 phase.   
   >>>>>>>>> That means 3 +ve power diodes, 3 -ve power diodes and 3 exciter   
   >>>>>>>>> diodes. If there is only one output wire, then all   
   >>>>>>>>> *rectification* and control has to be on-board.   
   >>>>>>>>>   
   >>>>>>>>   
   >>>>>>>> If the alternator really has DC output, then the car's [DC]   
   >>>>>>>> ammeter and external [DC] ammeter should register DC current.   
   >>>>>>>>   
   >>>>>>>> I believe somehow the alternator burnt the internal diodes, and   
   >>>>>>>> the owner rewired it as single phase [AC] output and used   
   >>>>>>>> external [bridge rectifier] after the car's dashboard [DC]   
   >>>>>>>> ammeter. That means the dashboard [DC] ammeter has not been   
   >>>>>>>> working properly ever since [because it was AC coming from the   
   >>>>>>>> alternator]. A germanium [bridge rectifier] was used so some   
   >>>>>>>> reverse current is flowing back into the alternator when the   
   >>>>>>>> engine is not running but the key is on auxiliary. That's when   
   >>>>>>>> and why the dashboard ammeter registers negative.   
   >>>>>>>>   
   >>>>>>>   
   >>>>>>>   
   >>>>>>> I've some made minor corrections in square brackets [ ] above to   
   >>>>>>> clarify my points.   
   >>>>>>>   
   >>>>>>> I think I have the correct line of thinking.   
   >>>>>>>   
   >>>>>>>   
   >>>>>>   
   >>>>>>   It must be quite difficult to blow smoke up somebody's ass with   
   >>>>>> your head so far up your own .   
   >>>>>   
   >>>>>   
   >>>>> Do you have a better explanation for a DC ammeter not registering   
   >>>>> any amperage at the alternator other than the alternator is   
   >>>>> outputting AC?   
   >>>>>   
   >>>>> The OP should try using AC ammeter to confirm that the alternator   
   >>>>> had been rewired to output AC, and external germanium bridge   
   >>>>> rectifier is used.   
   >>>>>   
   >>>>>   
   >>>>>   
   >>>>   
   >>>>   The simplest explanation is that the slip ring brush isn't making   
   >>>> the circuit to excite the rotor windings . That alone would explain   
   >>>> the voltage reading 12.8V while running - and slightly higher when   
   >>>> stopped and there is no current draw for stuff like ignition and   
   >>>> instruments .   
   >>>>   The next simplest would be that the internal regulator is bad ,   
   >>>> also resulting in a lack of charging .   
   >>>   
   >>> Your explanation cannot explain the phenomena the OP had observed:   
   >>>   
   >>> "No amperage reading even at 2000 rpm.  Battery voltage 12.6V.   
   >>> Battery voltage with car running 13.8V, however amp meter only reads   
   >>> 0 or negative with headlights on. Placed an after market ammeter   
   >>> between the alternator and the battery.  Same reading as ammeter in   
   >>> the dash.   
   >>> How could this be?  Alternator supplies voltage but no current."   
   >>>   
   >>> Apparently the alternator is charging the battery. My explanation,   
   >>> albeit convoluted, can explain exactly how it is possible. The   
   >>> previous owner didn't want to buy a new alternator and used this   
   >>> convoluted way to get by. The previous owner wired the alternator to   
   >>> output AC, and used external germanium bridge rectifier to get DC. My   
   >>> thought experiment can explain all the observed phenomena in this case.   
   >>   
   >> Ah, a thought experiment! That explains why you don't get it.   
   >>   
   >   
   > Then how do you explain the alternator can charge the battery with no   
   > apparently DC current output?   
   >   
   I can explain it but the issue is with you understanding it. A WOFTAM.   
      
   --   
   Xeno   
      
      
   Nothing astonishes Noddy so much as common sense and plain dealing.   
          (with apologies to Ralph Waldo Emerson)   
      
   --- SoupGate-Win32 v1.05   
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