B-275 positive ground cable

[ghostrider3591]

Can anyone offer any insight on why the b-275 diesel is positive cable grounded, or is it possible to reverse to conventional negative ground?

 

[wore out]

(quoted from post at 10:35:58 05/04/22) Can anyone offer any insight on why the b-275 diesel is positive cable grounded, or is it possible to reverse to conventional negative ground?

"Back in the day" a lot of vehicles and equipment were (+) ground, based on various theories on why that was a good idea (you can find more on GOOGLE).

When alternators become common in the 60's (-) ground became almost universal.

As to your tractor, battery connection polarity can be reversed AND the generator polarized before startup and USUALLY the charging system will work without issues at the other polarity.

If your has an Ammeter the leads will need to be swapped between the terminals.

The downside is that some mechanical voltage regulators are designed for longer life at their designed polarity (due to the choice of metals used in their internal contacts).

Info on contact materials and system polarity from a Delco charging system manual.

So the best advice here may be to leave it as it is, unless changing to an alternator, or you have a quality voltage regulator that is not polarity-sensitive. And that is a hard thing to know for sure.

 

[ghostrider3591]

Thank you for your response. Since the battery is only installed when operating, can't I reverse the polarity and run a cable directly to the solenoid from the positive battery terminal and put a jumper switch for starting without concerns of a charging system?

 

[wore out]

(quoted from post at 11:42:32 05/04/22) Thank you for your response. Since the battery is only installed when operating, can't I reverse the polarity and run a cable directly to the solenoid from the positive battery terminal and put a jumper switch for starting without concerns of a charging system?

If you want to do that, (operate the machine with no charging system) disconnect, insulate, and tie out of the way both wires to the generator.

IF the generator is still working that will prevent it from charging into an open circuit, which can damage the generator and/or the voltage regulator.

 

[ghostrider3591]

(quoted from post at 11:49:18 05/04/22)

(quoted from post at 11:42:32 05/04/22) Thank you for your response. Since the battery is only installed when operating, can't I reverse the polarity and run a cable directly to the solenoid from the positive battery terminal and put a jumper switch for starting without concerns of a charging system?

If you want to do that, (operate the machine with no charging system) disconnect, insulate, and tie out of the way both wires to the generator.

IF the generator is still working that will prevent it from charging into an open circuit, which can damage the generator and/or the voltage regulator.

Thank you!

 

[rvirgil_KS]

If you disable the charging system, why are you concerned about leaving it positive ground?

 

[ghostrider3591]

I don't know. I tried running a direct battery cable to the starter solenoid and jump the connections and nothing happened. I thought maybe negative ground might be necessary.

 

[rvirgil_KS]

Positive or negative ground will have nothing to do with starter problems. The starter will turn same way with either ground.

Check and clean both ends of both battery cables, EXPECIALLY the ground cable to frame connection. Also check the cables and cable ends. If any question replace the cable.

If the ground cable goes to any sheet metal or sub frame, move the ground connection to the main frame as close to starter as you can get it. May have to get a longer cable.