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(quoted from post at 18:26:13 01/26/22) 12 volt generator which post from
generator is hot one or both not running
or neither
Click to expand...
or any that I have seen, neither.
 
(quoted from post at 15:26:13 01/26/22) 12 volt generator which post from
generator is hot one or both not running
or neither
Click to expand...

NEITHER post should be "hot" without the engine running.

The posts are typically labelled "A" (armature), which is the terminal where charging current leaves the generator, and "F" (field), which is used to control the charging rate.

HOW the voltage at the "F" terminal acts depends upon whether it is an "A circuit" generator or a "B circuit" generator.

Typically, the "A" terminal stud is a slightly larger than the "F" terminal stud.

Some generators have a third "G" (ground) stud which connects to the "frame" of the voltage regulator for more accurate voltage control.
 

It would help if you identified the generator brand and what it is on. Armature post is usually power output. It maybe the larger post of the two. Depending on what generator, and type system it is, the field post may need to be grounded or it may need power supplied to it to make the generator charge. So, it helps to know what you are working on and what you are doing to give the best answers.
 
A typical old car or truck DC generator output is across the ARM post and case/frame/ground WHEN RUNNING OF COURSE. The FLD post connects to the internal Field windings and it receives either a regulated ground for an A circuit or a regulated voltage for a B circuit to control its output.........Sometimes the two posts are labeled ARM or FLD sometimes not. Often the ARM post is bigger since it carries the most current

For troubleshooting a charging system check out my link

John T
John Ts Charging Troubleshooting
 

Thanks for the flow chart John. I printed that one off!!! Alternators are easy compared to generator systems. I can use all the help I can get! :D
 
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