Register now to get rid of these ads!

Technical 8ba generator troubleshooting question

Discussion in 'The Hokey Ass Message Board' started by gearheadbill, Aug 14, 2019.

  1. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    Before I arbitrarily remove my generator and send it out for rebuild, I thought I’d take a unique approach (for me) and ask a couple of questions about what seems to be the trouble.
    Late 8BA with 12volt generator. Everything is working great except that I’m not getting what I would consider to be adequate charging voltage. Results are a depleted battery needing recharging. At idle, using voltmeter checking across the ground and field terminals, I’m getting 11.5 volts. As the rpms increase, the voltage increases accordingly to 12.8 volts at about 2000-2200 rpm, then falls back off to the 11.5 volt area. This backing off of full charge tells me that the regulator is doing its job in regulating the charge. But the whole shebang doesn’t give me enough juice.
    Any comments or suggestions appreciated. Thanks IMG_0620.JPG



    Sent from my iPad using The H.A.M.B. mobile app
     
  2. A 12v. generator should put out over 14 v. at elevated RPM (14.4 at the regulator output)
     
  3. 56shoebox
    Joined: Sep 14, 2011
    Posts: 1,106

    56shoebox

    I'm no electrical expert, but I believe it should put out at least 14 volts "when excited", meaning when the rpm is up over 1200. I read somewhere that Fords actually put out 15.5 volts.

    I know that doesn't answer your what is wrong question but it does give you a point of reference for output. I also am aware that you are checking the voltage at the generator, thus eliminating the chance of a bad external voltage regulator?
     
  4. Did you polarize the regulator?
     
    clem likes this.

  5. Rex_A_Lott
    Joined: Feb 5, 2007
    Posts: 1,148

    Rex_A_Lott
    Member

    No generator does very well at idle. Neither do they do well at high rpm because of brush float.
    You could:
    1- clean the commutator
    2- make sure the brushes are in good shape and seated to the commutator
    3-make sure the belt is working correctly.
    4- check every connection, including the grounds.
    I feel your pain. I recently went through yet another bout with the one on my 55 and I came this close “ll” to giving up and putting an alternator on it. My uncle used to say the solution was to get a generator for a 56 Ford and use it on the old flatheads. It worked for him, but I’ve never never had one so I don’t know what was different about them. Good luck.
     
    harpo1313 likes this.
  6. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    No. Never occurred to me. How do I go about that?


    Sent from my iPad using The H.A.M.B. mobile app
     
  7. Atwater Mike
    Joined: May 31, 2002
    Posts: 11,625

    Atwater Mike
    Member

    On the voltage regulator, there are 3 terminals. ('Arm', for armature, 'Bat' for battery, and 'F', for field)
    Touch the 'Bat' terminal to the 'F' (field) momentarily with a jumper wire. Only for a second. (energize the field)
     
  8. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

  9. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    Thank you. Using a jumper is even better. Don’t have to disconnect anything.


    Sent from my iPad using The H.A.M.B. mobile app
     
  10. 56shoebox
    Joined: Sep 14, 2011
    Posts: 1,106

    56shoebox

    So share it with us! What is Flat Ernie's method?
     
  11. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    No it's not " better". Ford generators are wired differently (Type B) than all other generators and so polarization is different than all other generators. Using a jumper wire on the Ford type regulator may damage it. I wouldn't risk it.

    Disconnect the FLD wire from the regulator terminal and touch it momentarily to the BAT terminal. (By '64 the manual said to disconnect both FLD and BAT terminals and momentarily connect them. CYA boilerplate I betcha)

    Here's an Echlin troubleshooting guide:

    http://www.packardinfo.com/xoops/html/downloads/1957-59EchlinSB.pdf
     
    56shoebox likes this.
  12. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    Truck64 is saying the same as Ernie did. Just to be safe, I will disconnect from the regulator prior to polarizing. We'll see if it helps.
     
    Truck64 likes this.
  13. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    Man, that Echlin guide is great. Thanks for making it available.
     
    Truck64 likes this.
  14. clem
    Joined: Dec 20, 2006
    Posts: 4,188

    clem
    Member

    Does anyone have knowledge on installing a dynamator on the same motor, is polarising the field terminal required?
    Thanks, and sorry if this is considered hi-jacking your thread, but I thought it fits here.
     
    Truck64 likes this.
  15. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    Somebody posted that over at the 'Barn. It is pretty good.
     
  16. 56shoebox
    Joined: Sep 14, 2011
    Posts: 1,106

    56shoebox

    This will answer the polarizing question once and for all.

    https://www.fifthaveinternetgarage.com/tech_tips_polarizing_generator.php

    For those of you who are technology challenged I'll post what the link reads:

    Polarizing a Generator
    "A" circuit generators (most GM models) strike the battery and armature posts together using a jumper wire or a pair of pliers, (spread the handles) and touch the two posts together briefly. You should see a small spark then you are done. You need to do this every time you remove either the generator or regulator for service.



    "B" circuit generators (most Ford Products) – DISCONNECT the FIELD wire from the regulator and strike it onto the BATT post on the regulator. When you see some small sparks you are done. Reconnect the field wire to the regulator. You have to remove the wire to polarize a “B” circuit generator. DO NOT use a jumper wire. You will need to do this every time you remove either the generator or regulator for service.



    "A" circuit or "B" circuit…?
    Look at the back of the generator; if the generator field wire is connected to the INSULATED brush you have an “A” circuit. If the field coil wire is connected to the NON-INSULATED Brush or Ground, you have a “B” circuit generator.
     
    Truck64 and clem like this.
  17. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    56shoebox....so glad we have people like you who can give us non-tech the Cliff Notes version of these things. Thanks!


    Sent from my iPad using The H.A.M.B. mobile app
     
  18. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    Ok. So I polarized the reg. Now output , measured at the generator F and Gr terminals, is 12.6v at idle. Running the revs up a little I can get a max of 13.4v, then it just dives to 8-9 volts.
    Any more ideas. Thanks again


    Sent from my iPad using The H.A.M.B. mobile app
     
  19. clem
    Joined: Dec 20, 2006
    Posts: 4,188

    clem
    Member

    Faulty regulator or it needs adjusting ?
    Is the battery ok ?
    OT , but for it’s worth - what you explain is exactly the same symptoms as my ride on lawn mower had. A new regulator and it is now fine.
     
    Last edited: Aug 15, 2019
  20. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    Want to always measure an alternator or generator under load, turn the headlights on and the fan blower, radio, etc. Then, run the engine up to simulate cruise RPM, say 2000 to 2400 and hold it there. Measure voltage right at the battery posts, cause this what counts. Remember what the Echlin service bulletin said about connections and grounds. Even a tiny bit of corrosion, loose or missing grounds, will cause problems. A quick test, take a heavy jumper wire with alligator clips or even jumper cables, ground the regulator case directly to battery ground terminal. If the regulator "sees" a different ground potential it won't work correctly.
     
  21. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    I don't believe that is totally accurate. The residual magnetism is retained inside the generator, whether the battery is disconnected/reconnected, or the regulator removed and replaced. The Ford manual says it isn't normally required to polarize a generator unless the generator has been rebuilt and the pole shoes replaced. It won't hurt anything, assuming it's done correctly. Polarizing Fords using the GM type "A" burns the regulator points.
     
    clem likes this.
  22. gearheadbill
    Joined: Oct 11, 2002
    Posts: 1,318

    gearheadbill
    Member

    I think I got some progress. Grounded case of reg directly to bat post ground. Read meter results directly at the battery. Best was 14.0 volts at 2000 rpm. Now checking grounds. Side note...I have almost no voltage leakdown ; less than .2 miilamp.
    Got better


    Sent from my iPad using The H.A.M.B. mobile app
     
  23. Sounds like you got it.Remember at idle generators dont put out much.As a kid slow cruising generator Chevys on Saturday night I couldnt even keep the battery charged enough to get it started the next morning.Rest of the week it was fine cause I drove on the highway.Theres a reason the alternator was invented.
     

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.