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Subject: charging troubles

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John B.    Posted 02-06-2017 at 18:37:15 [URL] [DELETE]        [Reply] [Email]  
  • charging troubles
  • I have a 48 8N with a 3 brush generator, positive ground, A-circuit.

    Here's the short version:
    I rewired the electrical system, installed a new regulator, and had the generator checked. After all this, the battery (less than 1 year old) charged perfectly. Fast forward two weeks and I notice that the ammeter stays at zero. Sure enough, it's not charging.

    I have done the following troubleshooting:

    1. Disconnected the generator and measured the output. It's around 20 Vdc.
    2. Shorted the field to ground. This causes the Generator to produce current in proportion to the RPM.
    3. Removed the regulator cap to observe relays. I found that the field relay (not sure if this is the cutout relay) I noticed that the when the contact is made, the system charges. As RPMs build, the magnetic field in that coil strengthens and opens the contacts. This causes all charging to stop.

    Remember, this is a brand new regulator. At this point, I'm not sure what I'm looking for. I am researching the function of the second relay.

    I just done want to throw in another regulator without understanding what is causing this one to act up.

    Any ideas?

    Tim Daley(MI)    Posted 02-07-2017 at 05:52:39 [URL] [DELETE]        [Reply] [No Email]  
  • Re: charging troubles
  • In addition to the 3-brush generator output specs, have you double checked the wiring, plugs to cap in right order? 1, 2, 4, 3 CCW? Also, recent complaints from fellas about defective aftermarket VRs is not uncommon. Which VR do you have? Should be the 8N-10505-B, before s/n 263844. Probably not needed, but have you polarized the unit? You're on the right track...

    Tim Daley(MI)

    Tim Daley(MI)    Posted 02-07-2017 at 05:34:55 [URL] [DELETE]        [Reply] [No Email]  
  • Re: charging troubles
  • Are you sure you are reading VOLTS and not AMPS? The 8N10000-A 3 brush generator should only output 6.5-7.0 VDC with 11.5 max amp output.

    Tim Daley(MI)

    JohnB    Posted 02-07-2017 at 07:32:53 [URL] [DELETE]        [Reply] [Email]  
  • Re: charging troubles
  • Tim,

    I was measuring voltage at the generator with the regulator disconnected. As one would expect, the voltage output was proportional to RPM (up to about 20Vdc). From what I know about gennys, this makes sense. I didnt measure the maximum current output, but when I "full fielded" the genny while connected to the regulator, the ammeter would register about 10 amps, which jives with the specs you provided.

    Tim Daley(MI)    Posted 02-07-2017 at 07:50:43 [URL] [DELETE]        [Reply] [No Email]  
  • Re: charging troubles
  • Here's a spec chart that may help out. If you need a good VR and/or generator, I have one of each, gen restored, VR slightly used, but tweaked for the 3-brush genny.

    Tim Daley(MI)

    JMOR    Posted 02-06-2017 at 21:39:06 [URL] [DELETE]        [Reply] [No Email]  
  • Re: charging troubles
  • The relay that has normally open (at rest) contacts is the cutout and it has heavier/larger contacts than the field control relay. The Field control relay contacts are normally closed (at rest). Those field contacts will open magnetically when battery voltage is high enough that it is not in need of charging.

    JohnB    Posted 02-07-2017 at 07:40:14 [URL] [DELETE]        [Reply] [Email]  
  • Re: charging troubles
  • JMOR, After doing a little more research, I have a better understanding of the operation of the mechanical regulator. It looks like the field contact should be vibrating at a high frequency (duty cycle based on voltage demand) - which its not. The cutout relay appears to be working correctly.

    I dont know the brand of regulator . . . it's one I purchased from Just 8N's or Steiner . . . I can't remember. I'm sure it's probably Chinese.

    Now that I know what I'm looking at, I can take a look at the original regulator (Neihoff brand) to see if I can do something with it.

    Tim Daley(MI)    Posted 02-07-2017 at 08:00:30 [URL] [DELETE]        [Reply] [No Email]  
  • Re: charging troubles
  • John-
    The last VR I bought was from Just8Ns, p/n 8N-10505-B. This is it pictured below, the slightly used one I mentioned above, and tweaked for the 3-brush 8N genny. It was made In The USA. Just curious, but have you put the old VR back on and gotten the same results?

    Tim Daley(MI)

    JohnB    Posted 02-07-2017 at 08:32:19 [URL] [DELETE]        [Reply] [Email]  
  • Re: charging troubles
  • Tim, I don't have the regulator in front of me, but I recall seeing the factory p/n and the words "6 volt positive A circuit" silkscreened on the top of it. I will look closer when I get home.

    The "original" regulator had some damage to the field contacts. There was enough build-up on the contact face that the two contacts stuck together. I have repaired it as best I can and plan to try it again this afternoon.

    The wiring on this tractor has been a mess since I bought it (hence, the need for a rewire). Only recently have I attempted to get it sorted out.

    JMOR    Posted 02-07-2017 at 09:27:00 [URL] [DELETE]        [Reply] [No Email]  
  • Re: charging troubles
  • Those field contacts may be steady closed, steady open, vibrating at various rates, all depending on state of charge of the battery.

    JohnB    Posted 02-07-2017 at 11:29:43 [URL] [DELETE]        [Reply] [Email]  
  • Re: charging troubles
  • Understood.

    Overall, this tractor has exceeded my expectations in every way. It's, by far, the best $1600 I have ever spent and does everything that is asked of it. It's my log skidder, lawnmower, driveway grader, earth mover, and trailer jockey.

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