JD 4020 24volt generator

[db 4020]

What is the easiest way to test my generator on a 4020to see if it is working? It is a 24 volt system. How many amps or volts should it put out?

 

[Bob]

"How many amps or volts should it put out?"

About 29 Volts @ 10 Amps.

You got a way to measure that, RIGHT???

 

[John T]

If you put your voltmeter across the series sum of BOTH batteries (available at the 2 big cables on starter solenoid), it should read around 25.2 volts just sitting there. Then when coupled to a good charging system at fast RPM the battery voltage (sum of 2) should rise to the 27 to under 29 or so volt range. Thats one way to see if the genny is working......... The open unloaded output of a genny dont tell ya all that much, its how it performs and to what voltage it can raise a battery its hooked to that matters more. Those original 24 volt system gennys dont set the world on fire even when working correct ya know.. Im NOT any expert on those 24 volt systems they can get hard to explain and troubleshoot even if there let alone over the net, sorry. The 2 batteries are joined in series and that center point ties to frame ground to get two 12 volt circuits (A & B up at switch) for lights etc but the genny and starter are 2 wire 24 volt isolated from frame units.

John T

 

[tim s]

A 'hill billy' way is to look into the end of it and see if you have some sparking going on around the brushes. They don't charge very much on a good day..

 

[David G]

My dad always said "take care of the volts and the amps take care of themselves". This means that you will always have enough amps if you have adequate voltage.

 

[jdiesel]

it really easy, put a meter on your starter post, with the engine running off of idle, you should see at least 25 volts, if not the next step is to unbolt the generator and throw it away. 80% of the time, all you will do on a 24 volt system is spend time and money and have no results. get a one wire alternator and a 12 volt Iskra starter, you wont believe how much better it will start, expecially in cold wether.

 

[Anonymous-0]

The first given rule to successfully service or diagnose any problem on a 24 volt system is you have to be smarter than the drawbar!

 

[John Heine]

I would venture to say field in generator is open.That was the main problem with the generator on these tractors.