Alternator Regulators | A and B Circuit

Ever wonder how Alternator Regulators work? Want to know more about the difference between A Circuit Field and B Circuit Field in Alternator Regulators. Well, I am going to show how all this works and how it pertains to the alternators we have in our cars today.

[raphialhebert]

This is an awesome explanation of how these circuits work. Thank you for such a good educational video! You couldn't have made it any simpler to understand.

[robertmiller]

Excellent description of the differences in circuits and development and changes in charging systems over time!

[ShafaqIftikhar-pwld]

GOLD GOLD GOLD info. Thankyou for the detailed video.

[gibbyrockerhunter]

Thank you so much. This was the information I have been looking for, without knowing the correct search terms. Its horrible bot knowing what one dosnt know. Lol

[nathanrice]

I didn't realize there were two ways of doing that. Good video.

[alohakarn]

Quite clear from your explanation. It s a good clip. Thank you very much.

[damianbutterworth]

Love the pin holding the brushes back. I do that. Well it`s the only way.

[congerthomas]

Thanks, i have been a mechanic for years, and never new their was a difference, Although i was able to fix the problems, until now on my own truck. It's overcharging so my sorce voltage is low! Thanks. Did have one with bad alt, changed then it went to 40 volts, the output cable was all but pinched into under boom. So it was a A circuit that wasn't getting supply thru the discharge post, single wire alt. Thanks again

[AutoDiagnosticsPK]

you earn a new subscriber Sir straight on first video....thumbs up for crystal clear video on the subject

[chipprouty]

What would cause a B style to overcharge 15.7v?08 Jeep Wrangler.Thanks.

[mikkolempinen]

Loose belt means less alternator rpm. Regulator has to increase field current to compensate. Brushes wear faster. I think polarity has an effect on which brush erodes first. Grooved belts have higher surface area and allow more power transfer than v-belts.

[robertrhoades]

I have a 99 Ford at 3:50 pick up 73 and the alternator is headed off and sucking can choose from the 2 batteries and I was wondering if you could help me fix that

[edherwick]

Excellent. Thanks. So, would a B circuit Alternator regulator work on a 2 brush B circuit generator (old Ford 12v diesel tractor)?

[jason]

Thank you SOOO MUCH for explaining this stuff so well! I knew there was a and b types, but never understood just how they worked differently.

I'm in the middle of a cummins swap project, and im redoing the wiring from scratch, and have to decide which voltage regulator type to use. It sounds to me that the ford style type B regulator is the better way to go, because +power is controlled to the alternator, and if it shorts out, it will only stop charging and maybe blow a fuse, instead of overcharging and maybe causing damage elsewhere in a type A setup.

Do you concur? What's your thoughts on internally regulated alternators, whether from factory or with an aftermarket module?

[petersack]

Very good, simple and concise explanations !. ? = i have a NEW alternator from a Dodge truck, 1500 1996 model. 120 amp Denso, i think; model A-8265A02AY7 IT has 2 small studs ; for A and B i assume. And, one large BAT terminal. I want to use it for my Dodge 1996 intrepid car - 3.3 litre engine. What would i need ? that external regulator, that clips onto those A and B studs ; or another method for education !

[coachmorange]

Thank you for explaining things in such great detail. I have a 2000 Dodge 2500 with the Cummings deisel. We replaced both batteries yesterday due to age and not cranking over. (They were each 4 years old). The truck started right up immediately, but the alternator gauge went to max charge, and is staying pegged when driven-18v. Beginning to troubleshoot now, with the knowledge that the batteries are new and good-but not wanting to drive it and do harm. Any thoughts on where to begin, as all the mechanics are a week or so out for diagnosis. Thanks so much for your thoughts, as I was planning to begin a 1200 mile journey to Indiana from Florida today! 🙏
p.s. the alternator gauge has never done this before.

[bernardocisneros]

So if A and B circuits are the way you explained them, can we say that A is negative controlled and B is positive controlled?

[jamiethomas]

This is very informative. Although, it appears there is no difference between an 'A' and be circuit alternator devices in regards to mechanical design or function as far as the rotor/stator/diode network? The difference appears to be the connections within the terminal block and how they interface with the regulator circuitry? The upper/lower slip ring explanation is confusing to me. isn't it the same connection to the rotor winding on opposite ends? The only difference would be polarity if they were swapped. Which would not matter since there is a DC rectification stage after the induction stage.. Correct? Additionally, what exactly is meant by 'insulated' in regards to the brush connection? Is it simply insulated from earth/ground as to force a path through the rotor coil to earth? Anyone..?

[deans]

My buddy's 12 valve Cummins always burned up the regulator until I installed a oil pressure switch for him.

[bearcountrypublishing]

Ok. I fail to see this before and after bit. AC flows both ways. So your wire going to positive or negative first has no before or after that i can picture. You're just completing the circuit. I feel it's more simple and more correct to just say A is controlled by the negative contact and B the positive. ??