8N Generator / Regulator Matching Trouble

8NKidd

Member
Hello everyone. I have a 1948 front mount 8N. A friend gave me a generator for an 8N, supposedly. I took it to my local mom & pop generator shop and had it rebuilt. The guy said it is A circuit, however, while the generator has good output, an A circuit regulator does not work with it. We are sure it is an A circuit regulator. The generator shop guy said to try it with a B circuit regulator. Does this sound right? I am lost. Is regulator part 8N10505B a B circuit regulator?
Thanks
 
Quick, find another repair shop, that one employs morons!!!!

If they had the Gen apart they should know circuit type!!!!!

Fields connected between armature and field tab are A circuit

Fields connected between ground and field tab are B circuit

You can full field and test Genny yourself to verify
 
I don't guess I understand what you mean. What exactly do I need to do to tell if it is A or B circuit?
Thanks
 
In case you did not read what I wrote.. i told you Exactly how to id a generator circuit type looking at how the field coils are wired up internally.

Fields connected between armature and field tab are A circuit

Fields connected between ground and field tab are B circuit


you can test this on the tractor.

gen installed and belted, armature wire hooked up.. but do not hookup the field wire.

have a volt meter on the battery and look at the ammeter.

start tractro get to mid throttle.

jump chassis ground to field on generator.

if charge goes to max on ammeter ( or 10-30a )and volt meter jumps up to like 7-9v, then it is A circuit if nothing, instead, jumper bat hot to field. if charge jumps up it is wired B circuit.

A circuit 8n regulator will have 1 bias resistor on the bottom, connected from ground to field tab.

B circuit ( naa thru 1964 4 cyl ) regulator will have 1 or 2 bias resistors, and one of them will connect from armature to field.

this help any?
 
Thank you souNdguy. I did read what you wrote, but I am 16 and have no experience in the generator electrical stuff. I was not sure what you meant by 'fields', but I do now. I'll try that test and report back.
 
no problem.

the tests are easier than taking the generator apart anyway.

the shop that told you it was A circuit but to try a B circuit reg must be looney toons. no way that would work!
 
I tried the test. A circuit. Grounded field to regulator base and pegged ammeter out at +30. Had voltmeter hooked to battery, went from 4v to 3v when I grounded field. Do you know why it would do that?

P.S. do you know which of these 2 VRs is A circuit?
8N10505B
or
8N10505C

Thanks
 
if te ammeter said +30.. then the battery had to show more than 3-4v it would likely have shown about 8v.

I'm thinking you did your voltage test wrong.

yes those regs are A circuit.
 
I made sure the voltmeter was hooked up right. Red on Positive and Black on Negative. I set the dial for 10 amps. It is the old analog type. Unless there is something else wrong?

If both regulators listed are A circuit, what's the difference between the two?

Thanks
 
Volt meters don't have amp settings.. You are hooking it up wrong or setting meter worng. Fir ammeter to show 30 a charge, there will be higher bolts on batter that 4.. /
More like 8-9
 
(quoted from post at 09:01:30 09/06/14) Volt meters don't have amp settings.. You are hooking it up wrong or setting meter worng. Fir ammeter to show 30 a charge, there will be higher bolts on batter that 4.. /
More like 8-9

Tried again. Hooked volt meter to correct terminals, and set dial to measure 10 V. When I grounded the field the ammeter pegged out at +30. Also, voltmeter went from 4V to about 2V and tractor lugged down.
?????
 
Sorry, if your 6v battery has enough charge to start the tractor, then reading 2-4v on it after start and running it is a physical impossibility. 2v wouldn't even run the ignition, for it to be 4 - 4.5v even, it would have to have a huge current load on it like a 100-200a drain starter.

Your meter is bad, or it is hooked up wrong, or you are reading it wrong.
 
(quoted from post at 05:50:21 09/08/14) Sorry, if your 6v battery has enough charge to start the tractor, then reading 2-4v on it after start and running it is a physical impossibility. 2v wouldn't even run the ignition, for it to be 4 - 4.5v even, it would have to have a huge current load on it like a 100-200a drain starter.

Your meter is bad, or it is hooked up wrong, or you are reading it wrong.
Ok. Will try a different meter.

But why would engine lug down when field is grounded?
 
when you ground the field, the generator jumps to making MAXIMUM capable output (at that rpm ).

that increased electrical load ( charging the battery ), is seen as an increased mechanical load.

no free lunch.. making electricity is not free.. it takes mechanical energy. IE. converting gasoline into electricity thru an internal compustion engine.

same deal with a portable generator.

you pour gas in the tank, pull the start rope and then can plug in your fridge to the genny when power is out.

you are converting gasoline into electricity.. ie.. converting the stored energy in the petroleum into mechanical energy, and then to electrical energy.
 

thanks for your help souNdguy. I finally got her to charge! I took your advice and found a different generator shop. They got it lined out. Thanks again
 
(quoted from post at 11:50:27 09/08/14) when you ground the field, the generator jumps to making MAXIMUM capable output (at that rpm ).

that increased electrical load ( charging the battery ), is seen as an increased mechanical load.

no free lunch.. making electricity is not free.. it takes mechanical energy. IE. converting gasoline into electricity thru an internal compustion engine.

same deal with a portable generator.

you pour gas in the tank, pull the start rope and then can plug in your fridge to the genny when power is out.

you are converting gasoline into electricity.. ie.. converting the stored energy in the petroleum into mechanical energy, and then to electrical energy.



SoundGuy....I would luv to shake your hands and buy you a cold beer. You took the time to help a young kid out. Not only answer but explain the very basic's of how his X-box works everyday.

Hopefully if he hangs out on this forum, an X-box is the last thing on his mind.

Keep asking questions kid!
 

Definitely! I do not have an X Box and wouldn't know one if I saw one! After all, where will video games get you in life? Tractors are my thing and I will definitely ask questions when need be!
 

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