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positive grounding on old oliver

Discussion in 'Repair & Technical Discussion' started by formulamx91, Apr 3, 2009.

  1. formulamx91

    formulamx91 New Member

    Apr 3, 2009
    Might seem like a silly question but how do you hook u a electric battery charger to a positive ground tractor
  2. Live Oak

    Live Oak New Member

    Dec 21, 2003
    Welcome to Tractor Forum formulamx91!

    Hook the allegator + or - clips from the charger to the corresponding + or - terminal on the battery. That way as far as the battery, charger, and system sees, it is apple and apples.

    It is best to charge the battery with the tractor battery cable leads disconnected from the battery. That way you are sure to be charging ONLY the battery and no other equippment left on drawing power or a possible short in the system.

  3. formulamx91

    formulamx91 New Member

    Apr 3, 2009
    Then how does the battery get charged when it is running?
  4. Live Oak

    Live Oak New Member

    Dec 21, 2003
    Positive ground charging systems run current in the reverse of negative ground systems.
  5. k1burner

    k1burner New Member

    Mar 25, 2009
    maybe a little simple but here goes my laymen terms of understanding........

    DC electricity want to go on a path from the + terminal to the Negative terminal, hopefully while on this path doing some work for us, (fan, light, starter etc..).

    With a negative ground system the + terminal is isolated from the tractor and a wire brings the current through to the "device" where the electricity does the work and then returns to the - terminal through the tractor, hence the reason the Negative terminal is "grounded" to the tractor.

    With a Postive ground the negative terminal is isolated from the tractor and current is sent through the tractor and is isolated back to the negative terminal through wires.

    Positive ground.... + Cable to the + terminal or to the tractor itself and negative to the - "negative terminal"

    I hope that made it as clear as mud
  6. jetdog

    jetdog New Member

    Jan 20, 2010
    Reverse Polarity

    We have an old 1958 Mack B-85 (505-cid Gasoline) with a Reverse Current Electrical System. We ALWAYS disconnect the battery when charging, that way you can simply charge the battery as you normally would (red-positive/black-negative). But once on the equipment, your right, the current runs backwards. One thing to remember with these old systems.....be careful in adding newer "solid-state" electronics like radios, etc.,.....the reverse current will usually blow them up! We had 2 old green/white Olivers, back in the '70s but can remember the charging system. But the Mack that has a Reverse Current System utilizes a Generator producing "wild" 3-phase A/C currents which then go into a big Transformer-Rectifier which produces the D/C current to the truck. I had to replace the T/R one time and it was really difficult to find, and that was all that really wanted to mess with, considering my limit knowledge. But Reverse Current systems are interesting nevertheless! Jetdog
  7. George G

    George G New Member

    Feb 12, 2005
    All good,execpt, DC flows from - to +.