Register now to get rid of these ads!

Creeping generator voltage

Discussion in 'The Hokey Ass Message Board' started by Truckedup, Mar 16, 2011.

  1. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,130

    Truckedup
    Member

    This is a 6 volt Autolite generator on my avatar Willys.It used to charge ok ,about 7.2 volts.Over the winter I checked out the voltage regulator and found the points inside were quite worn...So...I bought a NOS Prestolite regulator that is correct for this generator.Start it up ,run at a fast idle with the parking lights on and the voltage slowly,like a few minutes,creeps up to about 7.8 volts.Make a slight adjustment, then restart the engine ( manuals start to restart the engine after every adjustment) the voltage holds at 7.3 ,then slowly creeps up again.So after many attemps I figure the NOS regulator is fucked,buy a new regulator from a Jeep Willys speciality vendor.The regulator says "Made in USA",Great! Not! Doesn't work at all...Take off the cover and I see it's very cheap looking inside compared to the NOS unit.I also see very sloppy soldier job,pack it up for return.
    Back to the NOS regulator..I've adjusted many Delco units with no problem. This damn Prestolite just won't hold an adjustment.
    The generator checks out fine,ground out the field wire and it goes to full ouput over 8 volts and the brushes are like new.
    Anyone have something like this where the voltage won't stay in adjustment?
     
  2. medicinal_marinara
    Joined: Nov 24, 2009
    Posts: 139

    medicinal_marinara
    Member
    from Oregon

    Is your battery fully charged when you are doing this? You could be current limiting the output of the generator or opening the current limit relay while the battery is coming back from the engine restart, then the voltage creeps up after it gets charged enough to not draw so much current.
     
  3. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,130

    Truckedup
    Member

    The battery is charged and less than a year old.The regulator will hold a low voltage adjustment ,like 6.9 ,or a high one,but not around 7.3. The old regulator held steady at 7.3 but smart ass me had to replace it.And of course I threw out the baby with the bath water.
     
  4. medicinal_marinara
    Joined: Nov 24, 2009
    Posts: 139

    medicinal_marinara
    Member
    from Oregon

    It sounds like something is heating up and moving inside the regulator, making it impossible to calibrate.
     

  5. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,130

    Truckedup
    Member

    And something else,I get the adjustment around 7.3 volts,shut off the engine and restart or let it idle so it doesn't charge. Then let it run at a fast idle and the the setting stays at 7.3. Then I install the cover and the voltage setting goes to shit,usually much lower.Then go through the whole procedure all over again....When I got the NOS regulator it looked like a real virgin,no a mark on any screws.But on the back side the resistors looked like that gotten hot,not burned,but maybe they test these things at the manufacturing plant? That or i got a brand new piece of shit?
     
  6. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Could it be temperature change when the cover goes on?? Books on this stuff treat temperature as something that must be controlled for on regulator adjustment. A normal piece of kit was a temp gauge that snapped onto regulator cover fore determining the temp right there.
     
  7. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,130

    Truckedup
    Member

    The truck is in my heated shop, and yes I open the overhead door when the engine is running.:D On other vehicles I did notice a slight change in voltage when putting on the cover ,but on a 1/10 of volt or so.I also noticed on other regulators the voltage didn't change much as the battery got charged more after it was running for awhile.
     
  8. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    Try another battery if you have access to one. Sometimes batteries do funny things and age doesn't seem to matter.
     
  9. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,130

    Truckedup
    Member

    I took a long ride today and when I got back the voltage was holding steady at 7.2-7.3.Yup,need to get the regulator up to temperature.....I should know better,got all worked up over nothing :eek:
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.