D19 with alternator; Negative or positive ground?

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   As the title asks, we have a D19 that we took the battery off of long ago, but we can't remember which way the battery goes back on. Saw another topic asking about a positive ground, but we're unsure of whether or not that applies to ours, since we have an alternator. We assume that it's a negative ground, but want to make sure.

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Cmart009 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 23 Feb 2012 Location: Indiana Points: 3	Post Options Post Reply Quote Cmart009 Report Post Thanks(0) Quote Reply Topic: D19 with alternator; Negative or positive ground? Posted: 23 Feb 2012 at 7:10am
	As the title asks, we have a D19 that we took the battery off of long ago, but we can't remember which way the battery goes back on. Saw another topic asking about a positive ground, but we're unsure of whether or not that applies to ours, since we have an alternator. We assume that it's a negative ground, but want to make sure.

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Bob D. (La) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Louisiana Points: 25529	Post Options Post Reply Quote Bob D. (La) Report Post Thanks(0) Quote Reply Posted: 23 Feb 2012 at 7:21am
	Maybe Steve at B& B will chime in later. I've never been acquainted with a positive ground alternator. I think I remember reading or hearing they exist, though not sure and I'm certain very few in number.
	When you find yourself in a hole,PUT DOWN THE SHOVEL!!!

Don(MO) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Bates City MO. Points: 6862	Post Options Post Reply Quote Don(MO) Report Post Thanks(0) Quote Reply Posted: 23 Feb 2012 at 7:21am
	Welcome aboard. Without seeing your alternator I don't know for sure but all the alternators that get installed on tractors around here are negative ground. You might post a shot of the alternator and we can tell. Don
	3 WD45's with power steering,G,D15 fork lift,D19, W-Speed Patrol, "A" Gleaner with a 330 corn head,"66" combine,roto-baler, and lots of Snap Coupler implements to make them work for their keep.

Rfdeere Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 11 Sep 2009 Location: Idaville, IN Points: 3283	Post Options Post Reply Quote Rfdeere Report Post Thanks(0) Quote Reply Posted: 23 Feb 2012 at 8:47am
	The D19 came from the factory 12 volt, positive ground, charged by a generator. If it now has a alternater, 99% chance it is now negative ground.
	Randy Freshour,Member Indiana AC Partners, http://www.rumelyallis.com

Gerald J. Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Hamilton Co, IA Points: 5636	Post Options Post Reply Quote Gerald J. Report Post Thanks(0) Quote Reply Posted: 23 Feb 2012 at 9:19am
	Match up the connector size with the posts. They ARE fat and skinny ON PURPOSE. But if backwards the alternator is instant toast. Though if in adding the alternator which is most commonly negative ground they didn't swap the battery cables, you don't know. I'm not sure a positive ground Delco S-10 looks any different from the outside from a negative ground and my Delco alternator book says they were possible. Basically the dfference is where the forward and reverse polarity diodes are pushed in to the diode heat sink and then the polarity of the regulator. An alternator often will generate without a battery, with the sense terminal connected to the output, and turned fast enough. Then you could check polarity with a voltmeter BUT some alternators self destruct in that mode or run up a high voltage and destroy electronics in the vehicle. If you know the polarity of the ohmmeter function in your meter, you can check the output post of the alternator (disconnected from the world, and one polarity it should show a drop of two silicon diodes and be open the other way. You want the battery polarity so its open. If its digital and has an ohmmeter range with a diode check you want to find the diodes with cathode to the post for negative ground and anode to ground. For a less sophisticated test you can use the battery and a lamp. Say a dome lamp, about 1 amp 12 volts. Connect ONLY one battery post, then connect the lamp between the other battery post and the connector (preferably the to be grounded post for safety). If the alternator (all other circuits turned off or disconnected) makes the lamp glow full brilliance the battery polarity is opposite that of the battery. The lamp will limit the current that would destroy the alternator diodes with a direct connection Gerald J.

Steve in NJ Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Andover, NJ Points: 11926	Post Options Post Reply Quote Steve in NJ Report Post Thanks(0) Quote Reply Posted: 24 Feb 2012 at 9:02pm
	Originally it was Positive ground with the Generator doing the charging chores. A Gennie will charge pos. or neg ground. If moving to an Alternator, most Alternator's are NEG. ground. Install it and wire it NEG ground... HTH Steve@B&B