Need help--adapting a generic volatage regulator

[srjones]

I got good news and bad news from my local starter/alternator/batter shop. First the generator from my old Mitsi tractor (R1500 is good). However, the voltage regulator is dead. Dead, dead, dead.

I don't think it's practical/possible to find the exact OEM replacement, so I would like to find a generic (read cheap) voltage regulator like the ones you'd find at NAPA or places like this: Voltage Regulators

But I have no idea which one to choose, or how to choose. Are there any primers on voltage regulators I can read up on? Any advise on what to do?

I would really like to make this work, but if I can't I'll probably end up putting on an AC Delco 1 wire alternator.

-srj

 

[mech1119]

My experience with voltage regulators tells me that the one wire delco alternator might be the best way to go if you have room to install it. Voltage regulators for generators have gotten somewhat pricey over the last few years and if you combine the hassle of adapting one to fit, with the possibility of a generator failure down the road, then a one wire alternator seems to make sense. I priced a one wire at O'reilly's a couple of weeks ago, and it was about $78.00. I opted for the standard delcotron, as I was able to wire it pretty effortlessly and it cost me about $35.00. Hope that is of some help.

 

[srjones]

Here are the pictures of the current non-functional regulator. As I was taking the pictures, I started wondering...

What if just the diodes were bad? Can they be replaced? they've got numbers on them, but you can't quite see it in the picture. Could I bridge them and see if things started working?

Also, as you can see from one of the pictures, there are three tabs in front...A F B. Presumably, two would come from the generator and one would go to the battery. B= battery...could it be that simple? What would A and F stand for? How would I know (guess) which posts on the generator they'd correspond to?

Thanks in advance,

-Steve

 

[Fredex]

I'm going back a few decades on memory here, so call this a SWAG or maybe only WAG. Unless you can find a regulator listed for your tractor, you will probably need access to the specifications of the candidate regulator to match it to the specs of your generator. Gen regulators are different from alternator regs. Gen regs have, usually, 3 functions: 1. disconnect gen from system when its output falls below a certain voltage and reconnect when it rises to a higher specified voltage (cutout function); 2. regulate maximum output voltage; 3. regulate maximum output current. 1&2 aren't too difficult, but #3 needs to be matched to the rated max current of the generator. Also regs are made for pos. or neg. ground. Finally, I have a faint suspicion of a memory that some gens regulate the ground end of the field while others regulate from the hot side. Not sure, but if so would require different regulators.
All this can be sorted out but it is a bit of an engineering exercise.

 

[srjones]

My experience with voltage regulators tells me that the one wire delco alternator might be the best way to go if you have room to install it. Voltage regulators for generators have gotten somewhat pricey over the last few years and if you combine the hassle of adapting one to fit, with the possibility of a generator failure down the road, then a one wire alternator seems to make sense. I priced a one wire at O'reilly's a couple of weeks ago, and it was about $78.00. I opted for the standard delcotron, as I was able to wire it pretty effortlessly and it cost me about $35.00. Hope that is of some help.

I know what you mean..these are all factors I'm looking at if I were to go a one wire alternator. While I was at the shop, I saw one of those and I'm really not if I could make it fit without some major modifications. Also, are these meant to be exposed to the elements? I'm guessing not. The current generator seems to be pretty well suited for that.

But if I do go that route, I could do quite a bit with 60 amps.

Arrrgh...what to do? what to do?...

 

[Fredex]

Here are the pictures of the current non-functional regulator. As I was taking the pictures, I started wondering...

What if just the diodes were bad? Can they be replaced? they've got numbers on them, but you can't quite see it in the picture. Could I bridge them and see if things started working?

Also, as you can see from one of the pictures, there are three tabs in front...A F B. Presumably, two would come from the generator and one would go to the battery. B= battery...could it be that simple? What would A and F stand for? How would I know (guess) which posts on the generator they'd correspond to?

Thanks in advance,

-Steve

I don't think there are any diodes. The things under the can are relays and the spiral things under the bottom are wire-wound resistors.
I gave you a load of semi-technical junk in my previous post. Bottom line for most of us: If someone can come up with an off-the-shelf, general trade unit that has worked on that tractor, I would try it for a reasonable price. If not, go alternator.
Oh, A=Armature, B=Battery, F=Field; most probably.

 

[srjones]

I'm going back a few decades on memory here, so call this a SWAG or maybe only WAG. Unless you can find a regulator listed for your tractor, you will probably need access to the specifications of the candidate regulator to match it to the specs of your generator. Gen regulators are different from alternator regs. Gen regs have, usually, 3 functions: 1. disconnect gen from system when its output falls below a certain voltage and reconnect when it rises to a higher specified voltage (cutout function); 2. regulate maximum output voltage; 3. regulate maximum output current. 1&2 aren't too difficult, but #3 needs to be matched to the rated max current of the generator. Also regs are made for pos. or neg. ground. Finally, I have a faint suspicion of a memory that some gens regulate the ground end of the field while others regulate from the hot side. Not sure, but if so would require different regulators.
All this can be sorted out but it is a bit of an engineering exercise.

Thanks Fredex...I have no clue what the max rated output of the generator is, but it makes any difference, I only plan to run a few lights and keep the battery charged. The guy at the shop did tell me that the generator was putting out 17V, but he didn't write down what speed the tester was running at, nor do I know what RPMs the engine typically runs at (tach is broke). Oh, and just to confuse things more,I'm not completely sure if this is positive ground or negative ground.

I guess now I'm leaning towards fixing the regulator I have OR converting to an alternator...

 

[srjones]

I don't think there are any diodes. The things under the can are relays and the spiral things under the bottom are wire-wound resistors.
I gave you a load of semi-technical junk in my previous post. Bottom line for most of us: If someone can come up with an off-the-shelf, general trade unit that has worked on that tractor, I would try it for a reasonable price. If not, go alternator.

You're right. I should have known that. These are mechanical relays, no diodes required. Well, at least I can check the resistance with an ohmmeter an maybe replace? Yeah, I know I'm holding on to the idea...

Anyway, thanks Fredex for your advice.

-srj

 

[Fredex]

You're right. I should have known that. These are mechanical relays, no diodes required. Well, at least I can check the resistance with an ohmmeter an maybe replace? Yeah, I know I'm holding on to the idea...

Anyway, thanks Fredex for you advice.

-srj

You might start by checking out the contact points on the relay - may be burned so bad they are not making electrical contact when closed. Can be cleaned up with point file and maybe bent a little for good closed contact. Just don't mess with anything that changes spring tensions or armature gaps. Those control the regulated voltage, etc. When measuring the resistors, I would take one end loose just in case there is something in parallel with it. If one is open you will have to find the burnt spot and measure to both ends for correct value. And these are HIGH wattage resistors - how high I don't know, but may be difficult to find replacements of sufficient wattage that will fit the space.

 

[srjones]

BTW, the numbers on the resistors (that you can't really see in the picture) are as follows (top to bottom): 19, 10, 32

 

[PHIL850]

FYI: I believe the markings refer to the following:

F- for Field, A- for Armature and B- for Battery.

regards, Phil C.

 

[zzvyb6]

You might try a local junk yard filled with old Mitsubishi, Subaru, Datsun or Toyota vehicles. They would have had your voltage regulator parts in them from my experience. Tractor regulation is different from car regulation because tractors are usually run at higher average rpm and hours than a car. This means the charging systems have much less wattage, too. A junk yard is a reasonable place to walk around in with your old mount in hand to see what will fit in the engine location, offset and belt winding (direction, too). My Yanmar ate a regulator and it was VERY expensive ($80) to replace. Turns out it was the wire attached to the terminal inside the can. The problem was initiated by a bad battery terminal. The inability to pass low charging current caused the regulation to stay high all the time. This overheated the connector. I found this out when the new regulator also failed. I fixed this one based on disassembling the previous one. BTW: The tractor started fine because the high current draw of the starter bridged the corrosion in the battery terminal. The very low charge current could not.
Good luck. Bottom line: clean battery terminals and connectors as part of routine maintenance. Replace terminal end if necessary. Watch for corroded wire ends, too.

 

[Soundguy]

Ashas been said.. a=armature.. f=field, b=battery.. case may be ground.

No diodes in mechanical vibrating contact relay.

Mechanical voltage regulators generally fall into 2 categories.. A circuit, and B circuit.. and don't be surprised that some genny and alternator regulators will work on either unit.. genny or alt.. etc.

You need to decide which circuit it is... A or B

A circuit: regulator field tab provides 'ground' to the field coils in the genny.

B circuit: regualtor field tab provides 'power' to the field coils in the genny.

start tractor,
If reg type is's unknown.. start testing it. Grab a test lamp with a gator clip... hook clip to ground.. poke test probe to f contact on genny

jumper arm to battery... this bypasses the cutout.. if the ampmeter registers a charge when you hit the probe to the f tab ont he genny.. it is a circuit. if nothing, then hook gator clip of probe to battery hot, and then poke the f tab ont he genny again... if the ammeter registers a charge, then it is B circuit.

You don't mention.. but i am guessing 12v?

While you really should find what value the field coils are.. if it does turn out to be a 12v B circuit unit.. just grab a regulator for a ford diesel hundred series tractor... they will be 12v b circuit regulators.

I'm surprised that your repair shop couldn't have sourced parts for you.

I have an old hitachi alternator on my yanmar 1700.. it uses an old style chrysler regulator onit.. works fine...

Post back if ya need more help.

gennies are fairly bullit proof...and fun to work on they either need field power.. or field ground.. just depends where the field coils are hooked up internally ( to arm or case.. )

Remember to unjumper/bypass the arm / battery connection after your test.. otherwise the genny will discharge your battery..

Soundguy

Here are the pictures of the current non-functional regulator. As I was taking the pictures, I started wondering...

What if just the diodes were bad? Can they be replaced? they've got numbers on them, but you can't quite see it in the picture. Could I bridge them and see if things started working?

Also, as you can see from one of the pictures, there are three tabs in front...A F B. Presumably, two would come from the generator and one would go to the battery. B= battery...could it be that simple? What would A and F stand for? How would I know (guess) which posts on the generator they'd correspond to?

Thanks in advance,

-Steve

 

[srjones]

Mechanical voltage regulators generally fall into 2 categories.. A circuit, and B circuit.. and don't be surprised that some genny and alternator regulators will work on either unit.. genny or alt.. etc.

You need to decide which circuit it is... A or B
A circuit: regulator field tab provides 'ground' to the field coils in the genny.
B circuit: regualtor field tab provides 'power' to the field coils in the genny.

That sounds like the question to answer. From there, hopefully I can find a suitable replacement.

start tractor,

I would if I could, but the reason I went to the shop in the first place was a dead starter.

If reg type is's unknown.. start testing it. Grab a test lamp with a gator clip... hook clip to ground.. poke test probe to f contact on genny

jumper arm to battery... this bypasses the cutout.. if the ampmeter registers a charge when you hit the probe to the f tab ont he genny.. it is a circuit. if nothing, then hook gator clip of probe to battery hot, and then poke the f tab ont he genny again... if the ammeter registers a charge, then it is B circuit.

You don't mention.. but i am guessing 12v?

yep, 12V

I'm surprised that your repair shop couldn't have sourced parts for you.

Oh, I'm sure they could have. However, I didn't ask. I'm still reeling from the repair bill on the starter. When I go back on Monday, I can. Even better, I can ask an intelligent question like:

Does this generator require a 'b circuit' or an 'a circuit' regulator?

Post back if ya need more help.

Will do, thanks

 

[srjones]

Hi Soundguy...you got me thinking and reasearching and I found something on a different forum.


Yesterday's Tractors - Discussion Forum

Heres a quick check on the regulator. Flip it over.. look for the bias resistor.. An A circuit regulator should have a bias resistor between the field contact and ground on the regulator. On a B-circuit regulator there should be a bias resistor between armature and field.. there may be other bias resistors present.

Sound familiar?

Anyway, I did just that, and I'm pretty sure it's a "B circuit". The picture I uploaded at the start of this post doesn't label it, but the tabs on the right are the field and armature.

Thoughts?

http://www.tractorbynet.com/forums/...d-help-adapting-generic-volatage-p1050483.jpg

 

[Soundguy]

That's my post you are quoting from ytmag..... and it generally hold true. Your reg is a bit more hi tech than the old ford regs that use only 1 or 2 bias resistors.. however.. my 'bet' is that it is b-circuit as well.

Once you get the tractor started, it will be easy to check. Wire it all back up to the reg.. start tractor, hook up gator clip to power, and take the probe of the test lamp and hit the field tab... if the ammeter doesn't go + then jumper arm and bat and repeat.

Also.. I didn't mention it.. but gennies and regs need to be polarized.

B circuit polarizes by jumpering bat to field momentarilly.

Uh.. don't do that part untill you figure out if it is really B circuit. Jumpeirng bat to field on an a-citcuit reg can burn field points.. faster than a nats wings..

Soundguy

 

[srjones]

Thanks Soundguy...yeah, I knew it was your quote.

So assuming that the regulator is correctly diagnosed as being bad, what would be my best (cheapest) option to replace it?

 

[Soundguy]

Well.. see what the 'shop' will charge you. I usually buy mech regs in the 25-40$ range.

If it is B circuit.. and 12v.. I'd seriously considder a ford diesel hundreds series reg.. as they will be 12v and b-circuit.

I have one here on my desk as a backup for the old shoddy lucas regulator that is on my ford 5000. The part number is 1406 12V P/N says made in use on it.. blue housing and metal base.. 3 tab.. A,F,B bottom has another #1CD

I'd probably look for something like that.. unless the oem reg the shop finds is similar in price.. then go with that.. etc.

At issue is the original field coil resistance.. and what current it was designed for... It may not be exact.. but should be close enough to work. If you don't plan to suck every ounce of power out of the system.. the mismatch won't be noticed probably.

Soundguy

 

[slowrev]

If the fit is tight go with a small one wire alternator. I think my Subaru uses a little 60 amp Hitachi with internal regulator. About 30% smaller that a delco 10SI.
Ben.