vikingminer49er Posted August 4, 2020 Report Posted August 4, 2020 Have a 1952 B-3-F with an alternator. Wondering how to determine if it is negative or positive ground. Thank you. Quote
Merle Coggins Posted August 4, 2020 Report Posted August 4, 2020 Is it a 6 volt alternator, or has the truck been converted to 12 volt? If 6 volt it could be either, and I don't know how to tell the difference. If it is 12 volt it is likely negative ground. 1 Quote
vikingminer49er Posted August 4, 2020 Author Report Posted August 4, 2020 Thinking it's part of an earlier 12-volt conversion. Appears to have ballast resistors on the firewall. Will get some photos of them today. Thank you. Quote
maok Posted August 4, 2020 Report Posted August 4, 2020 Check the battery terminals, coil connections, and ammeter connections for a clue to what may have been done for polarity. 1 Quote
Los_Control Posted August 4, 2020 Report Posted August 4, 2020 I would start by pulling light bulbs, I imagine if tail lights are 1157 you have 12 volt neg ground. 1 Quote
lostviking Posted August 4, 2020 Report Posted August 4, 2020 It's simple. Measure between the positive terminal on the battery and the frame. It you see positive 12 volts, then it is negative ground. 1 Quote
vikingminer49er Posted August 5, 2020 Author Report Posted August 5, 2020 Ballast resistors on firewall. No battery. Quote
Jim G Posted August 5, 2020 Report Posted August 5, 2020 Delco Remy, Chevy Alternator, I'd bet a case of beer that is a 12 volt negative ground. Can you find a model number on the alt. anyplace? A good partsman should beable to tell you from that if it is an oddball. I'd (and I'm by no means an expert) make sure everything is off (no idea what you might have for accessories,) and hook it up to a 12 volt battery negative ground and see what happens, worse thing is if it is wrong you might pop the diode in the alt. just sort of touch the ground and see what happens so you can disconnect it quick if it actualy is a positive ground alt. 1 Quote
Jim G Posted August 5, 2020 Report Posted August 5, 2020 Check for numbers on the Alt. and counter check them against this site https://alternatorparts.com/6-volt-alternators-negative-positive-ground.html their alternators look like Delco Remys! not sure what part of the world you are in, but in my part of the world on a working truck, I'd still bet on it being a chevy alt stuck in there. 1 Quote
lostviking Posted August 6, 2020 Report Posted August 6, 2020 On 8/5/2020 at 11:33 AM, vikingminer49er said: Ballast resistors on firewall. No battery. Then measure between the output wire on the alternator and chassis. Quote
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