Easy Generator Testing

[@tatatoofey]

Thank you for the video. In two minutes you provided the information I needed that countless other videos were lacking.

[@danjarvis6980]

Outstanding: the simplicity and technical instruction flow flawlessly. Well done sir.

[@FarmallDoctor]

Thankyou, sir!!

[@daryusharash7790]

Thank you so much. It made it so easy for me to test the (12 V) generator on my VW beetle.

[@davidsmith7631]

Thank you, straight to the point and so very helpful.

[@FarmallDoctor]

Thanks so much! I am very glad that I can be of help to my fellow collectors.

[@jamesrice6096]

Excellent!! To the point. Accurate info. No fake rural accent while some bubba tries to figure out what he's doing. We need more like you!

[@FarmallDoctor]

Thanks! I like to help out and share what I learned from the old boys that taught me, and tricks that I have come up with.

[@earlebubar1805]

Great video, use these methods to check the older Delco Remy 1100 series on early Piper aircraft. Same stuff apples. Thanks for posting this information

[@FarmallDoctor]

Thankyou! My family and I love older aircraft as well!

[@Michael-st1hl]

Very clear and precise explanation that is easy to understand. Thank you very much! A big help.

[@thedavesofourlives1]

brilliant, concise, clear, thanks!

[@Steventhedieseltechapprentice]

Thanks for the video. Going to try this on my Oliver 60.

[@Inflec]

In following this man's advice there is one big caveat regarding grounding the field (F) terminal of the generator. This should only be done on generators that use an externally grounded field (also known as an A-circuit field). There is also a B-circuit field, which is an _internally_ grounded field. In this configuration the connection to the F terminal must go to the hot (ungrounded) side of the battery, whether it's positive or negative, to get full output or to check the generator slowdown when motoring it. Ford used the B-circuit configuration almost universally in its vehicles which were equipped with generators. This would likely also be the case with its tractors. So it behoves anyone doing these tests to know what configuration your particular charging system uses for its field circuit.

[@jamescaneda9515]

Yeah that’s what I wanted to know. I have a 6 volt positive ground generator on an international pickup. The new relay states to ground it to reverse the polarity. I called the retailer and he didn’t know. I’m waiting for the AC Delco mfg to call back for information.

[@frankkeyes5849]

Great Video, Thank you!

[@Beemer540]

Sir, an excellent tutorial. I just dont quite understand the last part where you bypass the regulator. You only show the jumper cable ends at the regulator/ generator, are the other ends connected to the battery ? And if so on what should you see "a full charge" shown, does your tractor hav a charge gauge fitted? Mine doesn't.

[@FarmallDoctor]

Yes, in a sense, the jumper leads are connected to the battery. As in, a known good ground, and battery positive. Yes, most older systems have a volt meter or ammeter, but some only used a charge indicator lamp. You can test with a volt meter. Also, if your dash light does not come on when key is on, it may be burned out. If it is burned out, the system will not charge.

[@kennycriswell141]

So on positive ground like John Deere would you run negative to amateur and positive to ground?

[@FarmallDoctor]

That is correct.

[@kennycriswell141]

@@FarmallDoctorI appreciate your video. I've run your test on 2 of my tractors today and discovered that my voltage regulators are bad. Replaced one and got it charging. Gotta get one more. Again thank you for the information

[@FarmallDoctor]

@@kennycriswell141 glad to help!

[@marcmarin6236]

Great video. I have a 6v. pos. ground tractor. When you mention connecting a lead from battery pos to armature terminal, is the lead actually coming off the pos batt terminal (the one with the the mesh cable going to ground)?

[@FarmallDoctor]

No, the other way. When we say "battery positive" we are meaning the machine, not necessarily the battery.

[@marcmarin6236]

So is it safe to say, connect a lead from the neg. terminal (since mine is a pos gnd) and the other end to the armature of the gen? In other words, think of wiring it up in reverse? @@FarmallDoctor

[@FarmallDoctor]

That's correct.

[@ianrobinson9565]

A knowledge of electrical theory helps. I see a lot of videos and while the person posting the video may know what they are doing, the person receiving the advice may not understand what is being said. When I am teaching how to test and repair generator and regulator I always use the LUCAS ELECTRIC SYSTEM for explanation and circuitry. It is a very simple system and the 3 or 4 tests to do in the field can be done with a volt meter and a shorting wire.

[@cd4222]

Thanks for the troubleshooting tips!

[@jamescaneda9515]

Will this work on a 6 volt, positive ground? Do I place the leads as you did, or differently because it’s positive ground?

[@James-z2c7g]

I was curious weather he was working with positive or negative ground myself.

[@James-z2c7g]

I looked through the comments and he does confirm that he is working with a negative ground system. So I would imagine that for a positive ground system everything would be done backwards (except for the polarizing part which btw is not the procedure for old 2-brush ford generators). Let us know how your test goes.

[@FarmallDoctor]

@@jamescaneda9515 this 6 volt system is positive ground.

[@jamescaneda9515]

⁠@@FarmallDoctorNo, I heard I’ll take the negative lead that’s ground. RED is positive hot, BLACK is ground. Did I hear wrong? I need this information because I’m installing a new generator plus a new voltage regulator. Your video was the easiest to follow.

[@FarmallDoctor]

@@jamescaneda9515 sorry, when i say "battery positive" that is meaning negative.. Because of the positive ground. It was drilled into us during college training, and I can't stop saying it that way.

[@seanstroud4313]

Do I leave the battery hooked up and just run wire test wire or do I unhook battery? Positive ground 12 volt system

[@FarmallDoctor]

Yes, i leave the battery hooked up.. Just remove the wiring harness from the regulator and generator, and use the test wire.

[@johndawsonjr]

I purchased a 6 V voltage regulator. I can’t seem to find a positive ground one. Does it matter

[@FarmallDoctor]

It should be pos ground. I've never seen a 6V neg ground system in North America

[@johnmary1852]

Im missing something here.. I did all the test and tested all good but generator will not put out? why? When it is all hooked up it wont put out and with it all un hooked the generator wont put out.. If it will motor it should put out..? it all bran new. Any answers or help would be greatly appreciated

[@FarmallDoctor]

Re-check your wiring connections, check that the Ammeter is in good shape, make sure the belts are tight, be sure that your generator and regulator are absolutely grounded.

[@JacobAHull-nx6rx]

If the regulator is bad, will it cause no spark to coil. I have brand new coil and ignition kit installed but I still cannot get spark. I think I may have a gound but cannot find it. Also my ammeter shows no charge while system was running..maybe the ammeter is bad. Before my tractor stopped running it would run for a few minutes and then just die. Pretty sure my generator is good cuase my battery stays when running. I have 1950 Farmall H. Thks

[@FarmallDoctor]

Hi Jacob. Sorry for the late reply. Not directly... unless your battery goes dead while running. Ignition is fed directly from the ignition switch. Check for power to the + side of the coil first. Maybe a bad switch! I would have guessed a bad coil... if you have another coil to swap into it, that would be a good test. I had a new coil die on my W9. Check to make sure that the condenser is held tight in the distributor. I have had some that the new clamp was too large for the new condenser. it MUST be tight and well grounded. Test the ignition points by putting a test light on the wire coming out of the distributor. While cranking it should flash as the points open and close. Observe that when the light goes out, it is completely out. Some new points have a glazing on them and they may need polishing. I use ultra-fine 2000 grit wet-dry sandpaper from an auto supplier to polish them. Let me know what you find.

[@JSTEALTH]

Can this be done on a generator with a tach drive? Or should the tach cable be removed first?

[@FarmallDoctor]

It can be done either way. I would spin it by hand first to make sure that there isn't excess drag from the cable and tach.

[@tysonlarson1]

Is your Oliver Positive ground or negative ground?

[@FarmallDoctor]

This one is Positive ground. But when I say "battery positive" I am meaning the power side of the tractor. So that means that the power from the jumper wire comes from the negative post... not the ground side. (+)

[@edherwick6995]

Does this same procedure work on 3 wire generators?

[@FarmallDoctor]

A 3 wire generator such as a Lucas on a Ford tractor? No. They are polarized by connecting battery positive to field circuit momentarily.

[@edherwick6995]

@@FarmallDoctor It is 1959 MF 65, perkins diesel. Supposedly original generator rebuilt recently. No manufacturer visible on generator. New ammeter, wiring and regulator. There are at least 3 different wiring diagrams for this setup (or more). Not charging...trying to sort this thing out.

[@FarmallDoctor]

Make sure that both the generator and regulator are properly grounded. You can use a test light to verify. Put the test light lead clamp on battery positive and touch each component with the probe. It is a common issue. The regulator should have had instructions included for polarizing. If not, your rebuilder can instruct

[@mrfarmall-vk4gw]

Thanks for the info!👍

[@ronmckinley8406]

Is all this done while it’s still connected to the battery? Thanks for your help. God bless you!

[@FarmallDoctor]

"Motoring" the generator test is done with the wires disconnected from the generator and regulator. Polarizing and testing of the regulator is done with everything connected and the unit running.

[@ronmckinley8406]

This question is about to show my novice at best experience. Will starting the car and disconnecting the battery let me know if the generator is doing it’s job? (For reference) It’s on a 58 Oldsmobile Super 88. When sitting the battery stays charged but drains when driving it. I’ve had it serviced and the guy said it’s in proper working order. Is it possible the aftermarket electric fuel pump has something to do with it? Thanks for the help.

[@FarmallDoctor]

@@ronmckinley8406 that may work with some systems, but it's not reccomended. The best test is to check the voltage while it is running right on the battery posts, then move the test leads to the cables, and finally at the regulator to see if there is any change. Check, clean, and tighten all cable and wire connections. They can be finicky!

[@ronmckinley8406]

I Thank you very much for your time and sharing your knowledge.

[@pacoguerilla3097]

I need to mount new generator and regulator, but don’t know the proper wiring. So I’m stuck and will try my best, hoping not to burn circuits.

[@FarmallDoctor]

@@pacoguerilla3097 F on regulator to F on generator, GEN on regulator to A on generator, BAT on regulator to ammeter or volt meter. L on regulator if there is not always there, or not always used. That is a load circuit that goes back to the light switch. Not necessary.

[@pacoguerilla3097]

@@FarmallDoctor Thanks a lot !

[@grasshoppercrews1296]

My case will only spin if I use hot as ground and negative on armature , generator removed from tractor is this normal ?

[@FarmallDoctor]

It is polarized for positive ground. Some old generators are more finicky that way.

[@grasshoppercrews1296]

@@FarmallDoctor thank you

[@donvoll2580]

Good day We do'n't have W-6 or 4 any moreI just kept 574. I remember W-6 having generator or regulator having problems Thanks should have known this 20 yrs ago.

[@mystic24100]

Your battery is negative ground, right.

[@FarmallDoctor]

Yes.

[@PatHaskell]

Scared the crap out of me when it first sparked!!

[@Praising-Christ-JesusAllmyLife]

Boom

[@mikedieken155]

I'm sorry but I wish you would do a better job explaining the jumper connections you did to test the generator. The tractor is positive ground which gives me an instant head ache. I just don't fully understand what you are doing. Otherwise you do an excellent job of keeping to the point. So many just ramble on with meaningless garble.

[@FarmallDoctor]

"battery positive" Is a general term that we use to identify the "hot" side of the circuit, no matter whether the system is negative or positive ground. Ground is always referred to as ground in both. "Battery Positive" jumped to the A terminal makes the generator "motor" no matter if it is positive or negative ground. If you were to ground that A terminal, nothing would happen.

[@onetransmission7871]

I'm sorry but you definitely are not a mechanic. This is not how you check any generator.

[@FarmallDoctor]

LOL... Show us your method then.