Bad Regulator -- Again!

[Tom_Veatch]

Are the regulators on these machines a weak link? I'm replacing the one on my YM2220D for the second time in a year (with less than 20 hours on the last one).

Symptoms were/are:

• Alternator light is on constantly for any engine RPM from 0 to red line.
• Voltage across the battery terminals is the same (~ 12.5 volts) with or without the engine running. (Verifies no charging current reaching the battery)
• With the engine at about 1200 RPM and the alternator electrically disconnected from the wiring harness, the alternator is showing about 14 VAC. (Verifies the alternator is functional)
• With the alternator disconnected, the resistance between the alternator terminals on the regulator shows 0 ohms. (That don't seem right to me)
• With the alternator plugged into the wiring harness, the alternator wires get uncomfortably hot to the touch very quickly (Indicates a high amperage which seems to verify the alternator is passing current through a low resistance load).
• Voltage from the battery charging current output terminal on the regulator to ground is 0 VDC . (Now, I know that ain't right - should be numerically close to the alternator VAC output.)

So, I'm replacing the regulator - again! What should I be looking for that could be causing the repetitive failure of these regulators?

 

[tommu56]

Tom

most regulators control the field current in the alternator to control charge current.

I would look for an auto electrical repair shop that actually repairs starters and generator and alternators take regulator and alternator to them.

The ones around here are way cheaper for repairs than tractor dealer (he probably takes it to them any way) or new one.

the other choice is to put a chevy one wire alternator in.


tommu56

 

[kenmac]

Yep, Have the alternator checked . Or, you may burn out another rgulator

 

[Tom_Veatch]

most regulators control the field current in the alternator to control charge current.

Keying off your word "most", I'm wondering if that's truly the case here. From the tractor's wiring diagram and the measurements I've made, it looks like the regulator is simply a rectifier and logic control device for the alternator "idiot light" on the panel as well as a DC power source for the other indicator lights.

There are two conductors between the regulator and alternator. I'm measuring the AC voltage between those two conductors. It seems like there would need to be at least three conductors if the regulator controls alternator field current. I've assumed both conductors are electrically isolated from ground. Don't know that to be the case but will test that assumption tomorrow. I'll also look at the alternator output over a wider range of engine RPM. It it doesn't vary much from the 14VAC point over the full RPM range, I'm going to guess that it's internally self regulating.

I'm certainly no expert, nor do I have a schematic of the regulator, but it looks like those two conductors carry AC power to the regulator where it is internally rectified to DC and fed to, for lack of a better nomenclature, the regulator's charging current output terminal. That terminal provides charging current to the positive terminal of the battery via a common connection at the starter solenoid.

the other choice is to put a chevy one wire alternator in.

Now that is an intriguing suggestion. Do you have any references/suggestions that might be useful if I wanted to go that way? I assume the "one wire alternator" is self regulating and has internal diodes to rectify the AC to DC. Maybe with a little ingenuity, I could come up with a way to power the instrument panel without the control circuitry in the stock "regulator".

 

[reb]

This thread discusses the 1610 regulator. I suspect yours operates the same way.

www.tractorbynet.com/forums/yanmar/49205-1610d-volt-reg-wells-vr728.html?highlight=1610+regulator

Before energizing your new regulator I would carefully check the wiring for intermittent shorts and also verify all connections are clean and tight.

 

[tommu56]

tom
here is a link for 3 wire ones

Catalog

my local starter shop converted my wives 74 nova alternator over to one wire it was just a different part in alternator the rest of it was good cost about $20.00 20 years ago.


Edit

here is one on ebay
eBay Motors: HIGH OUTPUT CHEVY ONE WIRE ALTERNATOR 105 AMP (item 130152219327 end time Sep-16-07 22:07:46 PDT)
tom

 

[FL_Jerry]

Might want to check this out: Alternator and Generator Theory


Also, there is a link there for the pro vs cons of 3(4 with gnd) wire vs 1 you might want to consider.


FL_Jerry

 

[rock2610D]

Not sure this will help but I will give you my experiance with Alts and Regs. I fought this type of issue with my bronco. Its regulator had a ground wire that attached to the screw that held it to the body of the truck and the body was grounded to the motor then battery.

Problem was that the location where the regulator was hooked to body was a little rusted and the ground wire was not grounding the regulator. I had to take sandpaper and clean all surfaces where the regulator attached to the body and then cleaned the ground wire from regulator to the screw.

BAM all my problems were fixed.

 

[Tom_Veatch]

This thread discusses the 1610 regulator. I suspect yours operates the same way.

www.tractorbynet.com/forums/yanmar/49205-1610d-volt-reg-wells-vr728.html?highlight=1610+regulator

Before energizing your new regulator I would carefully check the wiring for intermittent shorts and also verify all connections are clean and tight.

Thanks, Reb, for the link. Interesting discussion although it rapidly got a lot deeper than I could follow. My knowledge of solid state devices is limited to what I remember of a couple of college physics courses from the mid 60's. But, best I could understand, sounds like they were talking about my "regulator".

 

[Mickey_Fx]

Have not had any electrical problems on my tractor so no firsthand experience. From what I've read and looking at the schmatic, I'm with Tom on these systems.

The alt produces A.C., no rectification internally and has permanent mags for the field. The "VR" rectifies the A.C. and shunts the excess current to ground to control the voltage. This is not unlike many/most small engines found in lawn and garden tractors.

This is not your typ auto alt.

My rememberer may not be working correctly this AM.

 

[stevem5215]

I put a GM 7127 on our Chinese FarmPro 2420. That was the best cost choice and only required a small wiring change. Mine is the 60amp one and depending on your mounting system you'll need to determine which model is right for yours as they have them in 90, 180, 270degree mounts. Ours bolted up fine except for a small difference in the length of the belt. And it uses the 3 wire system (which is good for slow rpm diesels to charge the batt over the 1 wire system). And the price is right at $35 versus the $200 for the alt and a regulator that didn't fix mine for $40.

Steve

 

[Tom_Veatch]

Thanks, Mickey. Your comments seem to match what I'm seeing in my wire tracing.

BTW, there are several posts to which I haven't made a specific response. I would like this to serve as a general "Thank you - I really appreciate it" to all of you who have offered comments and advice on this problem.

The alternator is not internally regulated. With it electrically disconnected, I'm seeing about 14VAC output at idle speeds and up to the mid to high 20's as the RPM gets up to around 2400. Thats with no load, so I don't know what the numbers would be with current flowing through some load.

I have noticed a small box on the firewall beside the VR that I'm unable to match up with anything in the wiring digram out of Hoye's Operating Manual for this model (YM2220D). It's not a "tiny black cube" as described in Hoye's description of the VR-522 regulator. It's aluminum colored, about 1 1/2 inches on a side, is marked as a Hitachi WI1-07, and has three wires; red, black, and yellow which disappear into the wiring harness. Haven't yet found where they come out. Anybody know the purpose of that component. DAGS, but no joy.

I'm getting more of an education in this machine's electrical system than I really wanted.

 

[Tom_Veatch]

I put a GM 7127 on our Chinese FarmPro 2420. ...

That's sounding like an attractive option - especially if I can't find what's blowing my VR and it happens again on the new one that's due tomorrow. From what I've read in the reference links provided by the kind gentlemen on this forum, it looks like the internally regulated "3-wire" configuration would be my first choice. I do want to keep the alternator warning light (and/or an added volt/amp gauge) and it might not be practical to do that with a "1-wire" configuration.

I can see one problem that will have to be solved to go with a replacement alternator. The "stock" alternator is quite short, fore to aft, and there is a U-shaped bypass (?) coolant hose immediately aft of it (~ 1/2 inch clearance). It may be difficult to impossible to find an alternator that would be a direct, "bolt-on", physical replacement without rerouting the hose or relocating the alternator.

 

[Pete Milley]

"I have noticed a small box on the firewall beside the VR that I'm unable to match up with anything in the wiring digram out of Hoye's Operating Manual for this model (YM2220D). It's not a "tiny black cube" as described in Hoye's description of the VR-522 regulator. It's aluminum colored, about 1 1/2 inches on a side, is marked as a Hitachi WI1-07, and has three wires; red, black, and yellow which disappear into the wiring harness. Haven't yet found where they come out. Anybody know the purpose of that component. DAGS, but no joy"

It may be your turn signal relay. It is on my YM2000

 

[2manyrocks]

Buried in the technical thread mentioned before is a suggestion that loose battery connections can wreck a regulator.

My YM226 manual says to check the amp output of the alternator and it should be at least 15 amps. Regulated voltage should be 13-15 volts or there's a problem with either the alternator or regulator.

If you take the alternator to a shop, they should have a bunch of other units and might be able to identify one that is small enough to fit.

Might consider installing a voltmeter and amp meter just to keep an eye on things since you've had so many problems? I had to replace one regulator several years ago, and it wasn't a cheap item.

 

[Tom_Veatch]

...It may be your turn signal relay. It is on my YM2000

That's what I'm thinking. The confusion in my mind comes from the wires not matching either in color or number the wiring diagram that I have. I'll probably find that you are correct if/when I pull the panel checking all these wires. I'm not absolutely, totally, 100%, convinced the wiring diagram is a completely accurate representation of the way this tractor is wired.

 

[Tom_Veatch]

Well, installed the new regulator, tested all the ground connections in the charging circuit (I think), put new battery terminals on - not sure that was needed, but the clamp bolts were rusted/frozen and the negative terminal came off awfully easy even without loosening the bolt - replaced a pigtail (14 AWG?) that looked like a "field mod" with 10 gauge to match the connecting wire. Everything, for the moment, seems to be working perfectly.

The old regulator's rectifier components (diodes? SCRs? Whatever?) were definitely shot - essentially zero ohms both ways. Was effectively a dead short across the alternator's output with zero DC output to the charging circuit.

We'll see what happens over the next few hours of tractor usage. Maybe the previous regulator had some weak components, maybe something in the tractor is overloading the rectifier, maybe....?

Alternator puts out a maximum of about 31VAC at 2500 RPM. If this regulator blows, I'll be looking very heavily at replacing the alternator with a self regulating (3-wire) system.

 

[blackd]

Tom, I'm glad you said your alternator puts out 31 A. So does mine, and when you said 14A I was a little concerned. I blew two regulators and then gave up. I just recharge the battery once a month. Been doing it for the past two years. Will follow up on the GM alternators

 

[Tom_Veatch]

Tom, I'm glad you said your alternator puts out 31 A. So does mine, and when you said 14A I was a little concerned. I blew two regulators and then gave up. I just recharge the battery once a month. Been doing it for the past two years. Will follow up on the GM alternators

You might check the resistance across the connections between the alternator and the regulator (blue wires). Thats where the output from the alternator goes into the regulator for rectification and regulation. And/or check the temperature of the wires coming out of the alternator with the engine running. On mine, the measured resistance was zero and the alternator wires would get painfully hot. Indications were that the alternator output leads were shorted together within the failed regulator resulting in high current out of the alternator. If that's the case with yours, I'd suggest that it might be advisable to unplug the alternator from the wiring harness to prevent current flow from the alternator. That high current might not hurt the alternator, but it sure can't be good for it.

I'll be putting a few hours on the tractor drilling some post holes and a little minor excavation in the next couple of days. We'll see if this regulator survives that operation.

It is nice that these tractors really only need an electrical source for starting - assuming daylight, offroad operation - so an inoperative charging system is just an inconvenience rather than a show-stopper.