3G Alternator Load Response Control (LRC) Demo

[Gary Lewis]

Some of you may not know what LRC does on an alternator.  So this video attempts to show you.

In Big Blue the ammeter has been reworked by Rocketman to be a voltmeter.  And the center mark represents about 12.8V and the top mark is 14.4V.  As you'll see when the engine starts the voltage goes to the center mark for a couple of seconds and then ramps up to the top mark smoothly.

That has stopped the chirp I frequently had on startup when the regulator told the alternator to take the voltage up to 14.4V immediately.  And that was with a serpentine belt and an automatic tensioner.  But the 2.5 second LRC has tamed that and there is no squeal.

[ArdWrknTrk]

Thank you for documenting this.
Many times I try to explain what load response control is and why, but if a picture's worth a thousand words a video is.... 30fps,  carry the one....

[Gary Lewis]

Welcome.  I was just realizing that the voltmeter's needle finally broke free of the peg when I also realized that you can visually see the effect of the LRC on the voltmeter.  Pretty cool.

I held the phone at just the right angle to also get the display on the Sony as I had it set to show voltage, but you know how many hoops it jumps through on startup and it wasn't done jumping when it was time to stop the video.  So I cropped it to take that distraction out.

[Jon M]

Gary, just want to pile on the kudos here because this has been very pertinent to my current project. Like a few others, I'm tackling the 3G conversion right now (albeit slowly). Based on research into a number of forums I picked up an newly built ACDelco alternator with the LRC (gray or white) regulator, and I've recently sent of my ammeter to Rocketman to be converted to a voltmeter. So when I get those back I'll be installing and hoping for a result exactly like this.

Anyway, all that to say, this post has been very educational. I know you're doing a lot of work on the site right now, but this could easily be a side segment for the 3G conversion page if you're feeling up to it.

[Gary Lewis]

Jon - I'm glad the post helped.  The regulator I have is the white/gray one, which is 2.5 seconds.

As for the 3G conversion page, I agree that the LRC bit needs to be in there.  But I just looked and a whole lot needs to change to make that happen.  I really need to spend time to clean up that page.

[Danny G]

Glad to see this as I'm going through my 3g conversion soon. Links to said regulator used?

[Gary Lewis]

This is the regulator.  But you can find it with the brush set for about that price so shop around.

[ArdWrknTrk]

I've mentioned Maniac Electric Motors before.
They really seem to care about service!

[Danny G]

Great! Very much a noob on this, is there any markings on the one that comes on the alternator that would tell me it's stats less running it and watching voltage? Maybe it's already got the pause or is that just not the "default"?

[ArdWrknTrk]

You can look at applications and see them offered in luxury vehicles (Lincoln's and Grand Marquis) as well as the Escort where the tiny engine would bog from the load.  (Hence LOAD Response Control)

I don't think LRC, which are typically white, was ever offered in a truck or donors like the Taurus/Sable.

[ArdWrknTrk]

NEW* Regulator for Ford 3G Alternators w/ LRC

•  12 Volt, A-Circuit, I-S-A Terminals, 14.6 Vset, 2.5 sec. LRC, White
•  Ford 3G Series IR/IF Alternators
•  MFR:FORD

Used On: Ford (1994-2003) , Mercury (1994-1999)

Replaces: F4RU10316AA F4ZU10316AA F4ZU10316AC F4ZZ10316A GR814 VR1738 F795 62-02-5625 35-207 35-207-1 F08-08 8050-514 1053 YR-F32 230-14030 102019 AFD6021 T802


Here are some part numbers you can cross, to get the engineering number you will find ON a part.
Also note "white"....

[Danny G]

The one Inorderd looks like it's out for delivery today. Definitely not white. I'll look around for the part.

[Danny G]

Also I totally got that Alternator on sale for $91.

[Danny G]

Well that was easy enough. Search F795 Voltage Regulator on Amazon. Found them unmarked to marked ranging from $11 to $40

[Gary Lewis]

Yep, that's the one.  You can usually find them mounted to the brush carrier for about the same price, although I've not looked lately.  But you'll have new brushes so you can easily move the LRC regulator onto your brush carrier.

[ArdWrknTrk]

That's an excellent deal for a 220A alternator!

Are you installing a pizza oven in your pickup?  

[Gary Lewis]

Wow!  That IS a good deal.  I'd buy one if I saw that kind of a deal.

[ArdWrknTrk]

So what makes it a 220A alternator?
The internal fans can't get bigger.
The diodes can't really get any bigger either....

[Gary Lewis]

I've asked that question multiple times.  The best answer I got was that they, not DB, have them wound specially to put out more current and they put 220A diodes in.  And with them if you want 440A you add on an external diode bridge.

[ArdWrknTrk]

Honestly, I had a Miller synchrowave welder that put out 220A.
It was the size of a small refrigerator and had fans that ran constantly when welding aluminum.

I'm not sure why anyone would need that, or how it could be packaged in a case this diameter.