6 Volt Generator How To Test

Hello, You're expertise on this Forum is a blessing to me!

How can I test my 6 or 12 volt Generator on my 8n tractor with the Volt Meter to check for correct voltage. What is the correct voltage for these respectively.
I want to test it on the Bench and on the Tractor.

Thanks to any and all!
walt

Here you go.

75 Tips

Walt.......iff'n you have a 6-volt genny, WHY do you wanna test it fer 12-volts???

Unless you have a source of rotation, you ain't gonna make enny volts on the Bench. You can use yer OHM meter function to test fer BAD brushes or shorted field coils. Field coils seldom go BAD. And you can "twirl" the pulley and listen fer BAD BEARINGS. There is an oil nipple that needs to be dribbled on with what ever engine oil yer using. Most brushes need HIGH-HEAT to be SOLDERED in.

As fer on the tractor testing, UNLIKE the 12-volt alternator on yer BelchFire-V8, yer 6-volt genny does NOT charge at idle. At about 1/3-throttle, yer genny will MAX volts at about 7.3-volts. Yer dashboard AMP meter will provide more information than volt meter.

As fer 12-volt alternators, I'd taker into most enny autoparts store for "free" testing. Simple, eh?

BTW, digital voltmeters don't like N-Tractors when running. Ittza technical thing. ........Dell, retired Calibration Lab Engr

Hello Dell, You are sharp as a tack!

You caught that one fast. As for the 12 volt, naw! (really from Ky) I don't expect to have a 12 volt, but if by some unheard of twist of fate a "bloke" wants to sell me a 12 volt Generator, me not knowing the difference, how I can check it out?

I'm really talking about a 6 volt 8n generator, how can I measure the voltage it is putting out?

Thank you kindly,
walt PS I like your wit! 8) [/b]

Bruce, Thank you. I will try my best to understand the diagrams and who knows I may become genius at this sort of thing.
Thanks again!
walt :?

If you really want to know if a generator is working and you do not know what to use or have avolt meter, take the generator to a mom and pop generator shop and have it tested.
If you have a good voltmeter, hold positive lead to positive post and negative lead to neg post on battery and with engine running rad the voltage. if you read battery voltage then the generator is not putting out. a 6 volt generator should put out a bit more than 7 volts.

(quoted from post at 14:37:08 01/23/15) Hello Dell, You are sharp as a tack!

You caught that one fast. As for the 12 volt, naw! (really from Ky) I don't expect to have a 12 volt, but if by some unheard of twist of fate a "bloke" wants to sell me a 12 volt Generator, me not knowing the difference, how I can check it out?

I'm really talking about a 6 volt 8n generator, how can I measure the voltage it is putting out?

Thank you kindly,
walt PS I like your wit! 8) [/b]

Click to expand...

e careful of your conclusions, because an unloaded 6 volt generator can output 17 volts & that's a fact!

JMOR
Thanks, I'll surely remember that.
Incidentally I am using some of your 8n information that I got from Google.
regards,
walt

Thanks Geiger, I shall save that bit of information and add it to my notes for "when I need to check a generator".
regards,
walt

If you go to the 'other n-series tractor web site, you will find a ton of self-help information in the How-To forum PLUS JMOR's excellent pictorials on correct wiring of any combination of systems out there. Like the fellas said here, a charging 6-volt battery will read about 7.5 volts but you'll need an analog VOLTMETER because as Dell said, digital circuitry will get all scrambled from those crazy electrons jumping all around. Bear in mind early 8Ns used a different generator than later ones. Early output was about 11.5 amps, later was 20 amps. You should verify generator is working first with the 'motoring test'. You need a good, working ammeter too. Unsure about your voltage regulator? A good, reliable starter/alternator shop will test all of your components usually at no charge, no pun intended. If you really have no clue where to start, take your battery; ammeter; generator; and voltage regulator to the shop and they can test and tweak anything right there and also tell you if there is a weak link like a poor battery. Forget 12 volt stuff for now as an alternator is different than a generator and will only confuse you. Bruce, JMOR, and Soundguy have all given the test for motoring a generator so try the archives here.


[i:654c4848f0][b:654c4848f0]<font size="4">Tim Daley(MI)</font>[/b:654c4848f0][/i:654c4848f0]<table width="100" border="1" cellpadding="0" cellspacing="0" bordercolor="#000000"><tr><td height="25" colspan="2" bgcolor="#CC0000"></td></tr><tr><td></td><td></td></tr></table>

Thank you Tim for your information. I shall check out the suggested web site. I copied your post to me for my notebook on "how to" check 8n generator.

A fellow my age (passed seventy long ago) learns something every day and I count it a blessing!
regards
walt

I installed a new post-style ammeter on my early 8N recently. When i first hooked it up, i had the polarity reversed on the ammeter so it was showing negative amps (i think it was -20amps). No big deal, I thought. I can just reverse the wires. When i hooked it up correctly a few days later after finally grinding out the hole in the dash to make it fit, it didn't seem to be showing any amps. Maybe a little movement. I checked today with a radio shack style amp meter and it shows 1.5 amps. This doesn't change if the engine is running at a slow idle or if I increase throttle.

Today my son pointed out that i had the Field and Ground wires reversed on the generator. Am I correct that there is a pretty good chance this has damaged the voltage regulator? Would that explain the ammeter reading?

I pulled all the wires off the generator and measured voltage between the Ground and Armature posts. That showed 1.5volts with an analog meter.

In case someone wonders, I measure 5v across the battery terminals.

I need some help interpreting the results of these tests. Does it sound like i've got a bad generator, regulator or both?

Thanks,
Dan