How to Predict Catastrophic GL1200 Stator Failure


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SlowTyper
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How to Predict Catastrophic GL1200 Stator Failure

Postby SlowTyper » Tue Oct 28, 2014 2:21 pm



THE OBVIOUS: If you ride it, it will fail!

THE SUMMARY: Install a voltmeter and watch it for abnormally low voltage readings. (It is typical for the charging voltage to drop when idling with the brake lights on. It is also typical for the charging voltage to drop when idling while the radiator fan is running.)

THE DISCLAIMER: A lot of stators have failed on GL1200s, and it would be presumptuous to think they all have failed in the exact same manner as mine. Thus, your mileage may (oops, make that will) vary…

THE LONG ANSWER… I thought that because I had eliminated the stator connector near the battery, and had soldered the yellow stator wires directly to the bike harness wiring, that I would not experience a stator failure on my ’85 Aspencade. However, since my GPS is able to display voltage, I programmed it to do just that – in big numbers. And I kept an eye on it whenever I rode.

Interestingly, after years of riding, I noticed this season that my battery voltage dropped below 14 volts for several seconds. As the summer wore on, I noticed voltage drops of a greater magnitude and longer duration. When the voltage stayed between 12-13 volts for a couple hours on my ride home from the Sturgis Bike Rally, I concluded that I had an impending problem! But curiously, after that trip I rode for another 100 miles or more before the battery voltage ever again dipped below the 14 volt mark.

Since I was [erroneously] convinced that soldering the stator wires would prevent stator failure, I looked elsewhere for issues. I eliminated the rectifier/regulator connector and soldered those wires too. I also beefed up the 12 volt connections at the top of the starter relay, and verified with a voltmeter that they were not giving even a hint of a problem. But the occasional voltage drops continued.

Finally, one day my charging voltage was below 14 volts when I arrived at home. So I quickly got out my multi-meter and checked to see if the stator was shorted to ground. It was not. I also put a clamp-on ammeter on each of the stator wires to see if the current was different on any phase. Those current measurements were inconclusive because my charging voltage returned to normal. The situation was very frustrating to troubleshoot.

Eventually, I connected up an oscilloscope to the stator output to look for clues to the intermittent fault. What I learned from that was that the stator output looked different during the first few seconds after I started the bike, provided that I was starting the bike after it had warmed up but had been shut off for just a minute or two. Previously, I noticed the charging voltage had been a little low when the bike was first started, but [wrongly] attributed that to higher charging current as a result of a slightly discharged battery due to having just cranked the engine.

Here are the oscilloscope waveforms:
GoodStatorPattern
GoodStatorPattern
BadStatorPattern
BadStatorPattern

The first picture is when the stator was working normally; the second picture is when the stator output was weak (ignore that the camera caught multiple misaligned sweeps; it was hard to get a good picture due to the fault being intermittent). You’ll notice that the polarity reversal in the first image is quick, while in the second image it is slow enough that the vertical lines are noticeably diagonal. This indicated to me that the problem in the stator affected the speed of the magnetic flux transition, in addition to causing less current output. (You’ll also notice a couple low voltage horizontal traces in the first image – these are the result of the regulator shunting the stator winding when the charging voltage reached the design maximum. Yep, it’s a crazy technique to use to regulate overcharging.)

Based on the oscilloscope patterns, I concluded that the stator definitely had an intermittent problem and needed to be replaced. This conclusion was further confirmed when I measured the open circuit voltage output of the stator. At idle, I measured about 30 volts between two of the phases, and only 3 volts on one of the phases when the failure was occurring. Clearly, one phase had a serious intermittent problem.

I did not see any burnt windings when I got the stator out of the engine, which was a chore I did not particularly welcome (and is well documented elsewhere in this forum). However, I did notice a broken winding wire. Additionally, the balls of copper at both ends of the break indicated that this open circuit had been arcing and welding itself back together numerous times.

Here’s a picture of the broken winding wire (the wire ends have been separated for this picture):
StatorBrokenWire
StatorBrokenWire


And for comparison, here’s a picture of a shorted stator from another GL1200:
FriedStator
FriedStator

You’ll notice that in this second image that some of the windings are fried, which explains why those windings have shorted to ground and the stator provided almost no output. (That rider removed most of the fuses in order to limp his Goldwing back home.)

I find it interesting in the case of my stator failure that even when the stator output was compromised, it always had enough output at highway speeds to prevent my battery from going dead. Thus, I would not have known yet that a problem existed – except that having a voltmeter display alerted me to periods of feeble charging. Had I not been watching my battery voltage as I rode, I can speculate that the additional load on the two good phases would have eventually caused them to burnout, which would have resulted in a catastrophic problem that I couldn’t help but notice – namely, a dead battery!

So, now I am wondering if this is how GL1200 stator failures often play out. That is, first a wire repeatedly flexes due to the jolt of magnetic energy when the regulator shunts the stator winding. And then this flexing results in the wire breaking in two. Which in turn results in the other windings being overloaded and poor charging. Which ultimately results in the stator shorting out and totally failing. Certainly the broken wire I experienced is functionally equivalent to a bad connection of one of the three stator wires in the notoriously unreliable connector next to the battery. And yes, I am certain this unreliable connector is to blame for the vast majority of GL1200 failures. But apparently, even when this connection is soldered, there is still a risk of one phase still becoming ‘disconnected’ (due to an internal failure like I experienced), which in most cases ends up resulting in shorted stator windings and a dead battery. Unless, of course, the open circuit on one phase is discovered beforehand!

So, my observation is that adding a voltmeter to a GL1200 can provide an early warning of impending total stator failure. It certainly did for me. I ended up riding at least 1000 miles after the first indication of trouble, without the failure ever becoming severe enough for the battery to go dead.



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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby WingAdmin » Tue Oct 28, 2014 3:10 pm

An excellent analysis of the failure mode. Good job!

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby Scot Thompson » Sat Nov 01, 2014 7:06 am

That is a great analysis of the GL1200 alternator problems. But I do not believe it is the coil windings that simply break. Rather it is the conformal coating that breaks down on the coil winding and that allows the shorting to commence. When enough current can flow to ground through the coating breaks, the weakest link somewhere will burn through. In your case it was the wire that burned out. Here is a post I wrote addressing why stators fail.

Stators are not truly the fault, all alternators have a series of magnets rotating within a series of field coils, or they have the field coils rotating within the magnetic field. That is how the alternating current is made. The Honda has the field coils fixed to the rear of the engine and the armature rotates inside this "stator" thereby producing alternating current. The problem here is not that "stators" produce full voltage all the time that is then regulated by an external rectifier/regulator but rather the regulating scheme used in this type of design. In our Hondas, the output is a parallel scheme (parallel to the battery terminals) and the way these are regulated to the voltage we need is to shunt the excess voltage to ground. This is not an unusual scheme. The alternator is constantly putting out all it's 360 watts all the time. It generates this constant output because the magnetic field is constant as a result of being a permanent magnet. That magnetic field that creates the alternating current in the field windings (the coils). This AC current is output to the rectifier and converted in DC current. That DC current is too high a voltage (65-70 volts or so) and it must be regulated down to 14.2 VDC or so and to do this regulation, some current gets used, some goes to ground and becomes heat. As long as you don't overload beyond the 360 watts, it doesn't matter how many lights you burn. The problem with the stator is that it is simply not robust enough to stand up to the constant amount of current flowing and generating heat within the field coils themselves. The insulation on the coil wiring eventually breaks down and a short is created and the stator fails. Honda did not design sufficient margin into the stator.

An alternator is just another type of generator that produces AC current, but rather than rotate the armature within the magnetic field of the Field Windings like a 1950 Chevy generator, the permanent magnets are mounted on the rotating component called the Rotor, and Field Winding are mounted on the stationary component called the Stator. (This is not the same as the Fields on a generator which are electro-magnets, the Stator is just an array of coils, no magnetics.) While some Alternators can have electro-magnets on the Rotor (hence the series regulated scheme wherein the current is controlled to the magnets to regulate the output), most motorcycles use permanent magnets on the Rotor. As the magnets spin, they induce a current in the coils of the Stator. Current flows first in one direction as one pole (say North) crosses the coil and then in the opposite direction as the South pole crosses the coil...hence alternating current. Back and forth, back and forth. Our classic Goldwings use a permanent magnet, floating ground, Alternator design and the Stator is that component with the multiple windings on it that so often fails. The Stator is not a series of magnets.

Alternators create AC current and this must be Rectified into DC current to be useful on a motorcycle. In order to keep the size of the device small, 3 separate Field circuits comprise the Stator. It is smaller and lighter to have a 3-phase design than a single phase design. The three phases are combined into one output within a Bridge Rectifier that converts the Alternating Current into Direct Current - the rectification does not reduce the voltage. That is the job of the Regulator and it reduces the high voltage (now DC) down to a target of about 14.2 VDC by shunting to ground. That target voltage is a function of the values of the capacitors and resistors designed into the solid state device (the Silicon Control Rectifier). During this shunting process, each of the 3 legs of the now-DC current are measured against the control values and switched between output and ground. This happens very fast and actually is like a dithering on/off to regulate the voltage output of the Regulator. Indeed, it is an actual switch, albeit a solid state switch, that dithers on and off to shunt to ground. This is where most of the heat in the R/R is generated as this switching process is actually grounding the output of the alternator and wasting the current in the form of heat....60 watts or so in the case of our GL1200

So, in my opinion, what Honda should have done is to have simply designed and manufactured a robust stator design that was up to the task. They didn't and we all live with the nuisance.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby WingAdmin » Sat Nov 01, 2014 7:22 am

Interesting that you mention the coating on the windings that breaks down, leading to shorting out. I remember reading some time ago that a reasonable statistical sample was done measuring oil acidity in those bikes being presented where stators were being replaced, and a large representative sample of those had high acidic content - i.e. the oil was not changed often enough.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby flash1942 » Sat Nov 01, 2014 11:24 am

A lot of good info here. I agree that Honda should have designed it better but I still wonder why they think the idea of running the stator full tilt 100% of the time is good engineering. To me it's asking for a failure. And Honda isn't the only company to go that way. It puzzles me that they used a different alternator for the CB750. What happened to that idea?? And of course some are guilty of overdoing bells and whistles and overloading the electrical system's capacity which leads to failure.

So that's why I'm waiting for my series RR to come in and put on my 1200. If it works as well as I expect then I will get one for my '83 Silverwing. I may be barking up the wrong tree too but time will tell.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Sat Nov 01, 2014 12:11 pm

I understand that there are many reasons for any failure. What i don't understand is that a couple of times I have replaced a stator, shorted to ground and gotten only about 12.5 volts output. Even when the regulator was changed, the same results. All the grounds were cleaned and connections cleaned or replaced.
What other conditions can reduce the output voltage at the battery? Can the rotor be bad??
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby triwing » Sat Nov 01, 2014 2:11 pm

Insulation is second paramount in any wire situation only to the gauge of the wire,& connections. Acidic oil could possibly factor into the situation,but a better design has had to have been available.The replacements in my experience,all have much thicker wire used,work well and hopefully will last at least as long as the original's, but who knows if or when a better idea will remedy the situation?

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby WingAdmin » Sat Nov 01, 2014 2:15 pm

triwing wrote:Insulation is second paramount in any wire situation only to the gauge of the wire,& connections. Acidic oil could possibly factor into the situation,but a better design has had to have been available.The replacements in my experience,all have much thicker wire used,work well and hopefully will last at least as long as the original's, but who knows if or when a better idea will remedy the situation?


I've always wondered if taking a new stator and potting the windings in epoxy would help. It would keep vibration to an absolute minimum, protect the insulation on the windings from the oil, and help conduct heat away.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby SlowTyper » Sat Nov 01, 2014 9:11 pm

flash1942 wrote:I'm waiting for my series RR to come in and put on my 1200.


Where did you find a series RR?

I looked for a series design RR (rather than shunt), but did not see one for sale. But being convinced that a series design would improve the reliability of GL1200 stators (second only to soldering the three yellow stator wires), I intended to [and still may] build my own. However, I ran into some unexpected circuit requirements and have postponed that project for now.

I am convinced that in this particular stator failure, the windings NEVER shorted to ground. If they had, this would have resulted in some discharging of the battery at highway speeds. But in my particular situation, I always observed some minimal charging except at RPMs below about 1300. On my particular Aspencade, this corresponds to about 15 amps of stator output.

WingAdmin wrote:I've always wondered if taking a new stator and potting the windings in epoxy would help.


I am convinced this might help a lot. In fact, in my replacement stator [made by Ricks Motorsport Electric] the windings were well covered with a very hard coating. And I was glad to see that because I am convinced in my case the winding wire broke [in a location not wrapped tightly around a core] from fatigue from constant flexing due to being loose.

And just to clarify, it appears to me that the SCRs in the regulator are connected directly across the three stator wires, and crowbar the stator windings directly (based on the voltage when crowbar action occurs). Also, the voltage threshold for the regulator appears to be measured at the regulator output, rather than at the wire from the ignition switch that goes to the regulator. Apparently, this 'switched power' wire only enables/disables the crowbar circuitry, and does not affect the regulated voltage threshold. In fact, when the key is turned off, there is a burst of voltage coming out of the regulator until the motor stops turning, since the crowbar circuitry is immediately disabled but the motor does not stop rotating immediately. In most cases, this burst of voltage is a non issue because the stator is so weak it does not exceed 14 volts at idle. However, in my case, since I have beefed up the size of the stator wires and also the size of the wire going to the battery, the voltage momentarily jumps up significantly when I shut the bike off. This anomaly means that one should be careful not to shut off the bike when the engine is running at a high RPM (such as when the choke is on) -- otherwise really high voltage could reach the 'always on' circuitry (clock).

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby SlowTyper » Mon Nov 03, 2014 12:31 am

wingingit2 wrote:What i don't understand is that a couple of times I have replaced a stator, shorted to ground and gotten only about 12.5 volts output. Even when the regulator was changed, the same results. All the grounds were cleaned and connections cleaned or replaced.
What other conditions can reduce the output voltage at the battery?


I would suggest looking closely at the wiring between the regulator and the battery for excessive voltage drop, presuming the regulators you tried were not both bad. I say this because the charging voltage is regulated by the regulator circuitry based on the voltage measured at the output of the regulator. So...

For the sake of discussion, assume the voltage at the regulator output is 14.5 volts. Also assume that because of the minimal wire size Honda used, the voltage drop in the wiring going to the battery is 0.5 volt. That would result in 14.0 volts at the battery.

However, the connection at the top of the starter relay may be bad and dropping another 1.5 volts. Another possibility is that there is voltage drop at the main fuse. But if that connection was very bad, it would probably create enough heat to blow the fuse.

Another possible scenario is that the battery has a shorted cell, which would result in more charging current than the stator can generate. But with a shorted cell, you would notice less than 12 volts of battery voltage when the bike is not running, and unusually slow cranking RPM.

One relatively simple way to reduce the voltage drop between the regulator and the starter relay connector is to add a jumper wire between the regulator output and the 12 volt power wire going to the ignition switch; you can tap into the 12 volt power lead at the point it goes past the regulator, or even where the key switch connector is on the right front side near the fairing. This allows charging current to go more directly to the 12 volt power systems, rather than traveling nearly all the way to the battery and back. It also reduces the current (by up to about 15 amps) on the wire going from the regulator to the battery, which in turn reduces the voltage drop along that wire.

In my experience, it is the voltage drop along this red regulator output wire and the voltage drop of the yellow stator wires that results in little to no charging at idle. Once I beefed up this wiring, my stator puts out a full 14 volts at 1200 RPM (and even at less RPM when the radiator fan was not running).

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Mon Nov 03, 2014 10:09 am

OK, just to be clear. Regulator output wire is R/W. Power lead to Ignition Switch is Red, and voltage drop can be measured with the key on and engine off at each connector in series.

1) Check R/W from Regulator to Battery and replace if needed.

2) The suggestion is to bypass the main fuse from regulator to ignition switch @ fairing RH connector. I would need to fuse that wire, correct?

I have also considered replacing the 3 Yellow wires from the stator connector to regulator but wasn't sure if there were any hidden connections in between. They have seemed pretty stiff. Do you know what the AC voltage of the yellow wires, on a Rick's, stator is supposed to be.

What gauge wire does Honda use here?
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby SlowTyper » Mon Nov 03, 2014 8:52 pm

wingingit2 wrote:The suggestion is to bypass the main fuse from regulator to ignition switch @ fairing RH connector. I would need to fuse that wire, correct?


I am sorry I was not very clear on my suggestion... My 'jumper wire' suggestion was not intended to imply bypassing or adding a fuse. The objective was merely to create a shorter path for most of the current flow.

As wired from factory (at least on my '85 Aspencade), power flows through a R/W wire from the regulator output to the connector on the top of the starter relay, and then back to the front of the bike through the R wire. There is no fuse in this section of wire. The R/W & R wires join at the top of the starter relay and then connect to the battery through the 30 amp main fuse.

Perhaps a better way to explain my 'jumper wire' suggestion would be to say to have the R/W & R wires connected together not only at the starter relay (the factory implementation), but also connect them together near the regulator (which results in a shorter path for most of the current flow, and thus less voltage drop).

One might wonder why Honda did not implement a shorter path for the current when they designed the GL1200. Well, I don't know! I can speculate that they may have been concerned about "alternator whine" in the intercom, and wanted the two wires joined at a very low impedance point (as close to the battery as possible) to minimize 'static' on the 12 volt power buss.

I don't know what size the yellow wires are, except that I thought they were a bit small for 20 amps of current flow. The actual voltage drop along the yellow wires is only an issue at idle, since at higher RPMs the regulator will adjust for any minor voltage drops (obviously though, the system can't compensate for a huge voltage drop at the notoriously unreliable yellow wires connector to the left of the battery).

I do not know what the output of the 'Ricks Stator' should be. But I can tell you it is a lot. It will keep my battery near 14 volts at a 1000 RPM idle. However, my bike is not typical. I have converted most of the incandescent bulbs to LED, and converted the headlight to HID. I have also added LED driving lights. In addition, I have added a cellphone booster, GPS, and subwoofer amp (sub is in trunk). Oh, and I almost forgot to add that I occasionally pull a trailer, which has tail and marker lights. During all my modifications, my target was to not exceed 18 amps power consumption so that there would be some current left to recharge the battery after blowing the air horns (powered by two air compressors).
Last edited by SlowTyper on Tue Nov 04, 2014 12:16 am, edited 1 time in total.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Mon Nov 03, 2014 9:38 pm

Thanks Slowtyper that clears it up. I will be trying this on a 84' GL1200A in the next week or so.
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby Scot Thompson » Tue Nov 04, 2014 8:47 am

A series regulator will do no good with a permanent magnet alternator. However, you can improve the situation with the R/R on these old wings by using a MOSFET R/R. I the factory SCR, the heat one feels is mostly from the swiching going on internally (in the silicon) that shunts the unused power to ground. This happens on all 3 legs of the output of the alternator to the R/R and that is a good thing as some really cheap designs just shunt one leg to ground to regulate the voltage. This switching consumes some power and it takes some time. When the electrical current is switched to ground, it is wasted and we feel that as heat. In the case of the SCRs on the GL1200s, that amounts to about 66 watts...or about the amount of heat a 60-watt light bulb puts out. That is why the R/R is not all the time. But it is designed to deal with this amount of heat, so they should function for a long time. In a MOSFET R/R, the switching function is vastly quicker than the older SCR design and therefore less power is consumed regulating the voltage level. So more power is available to operate the bike; you still have the same shunting to ground occurring though.

Why the series regulator is not useful for a permanent magnet type of alternator is that in a series regulation design, the magnets on the rotor are electro-magnets that require some input voltage to produce a magnetic field. The more voltage supplied to the electro-magnet, the stronger the magnetic field created. The stronger the magnetic field is, the higher the output of the stator as the magnetic fields pass by the coil windings. No input to the electro-magnets, no output of the stator. This is how the level of power is regulated on a series design. On the GL1200s, the rotor contains permanent magnets that produce a constant magnetic field...always, even at rest. These magnetic fields, when rotating, pass by the stator coils and in doing so, an electrical current is induced. The faster the rotation of the constant strength magnetic field, the higher the level of current created at each coil of the stator. Nothing regulates that except the speed of rotation of the rotor. So, in order to regulate a permanent magnet alternator, the power is shunted to ground and turned into heat.

When the stator component of the alternator starts to "bleed" to ground, on one, two or three of the phases, it is still possible to have some output. Even as the electricity is going to ground. Each of the three legs (the phases) of the stator will produce about 70 VAC, so if, say, a short to ground is consuming 40 volts, there is still 30 VAC being passed to the R/R. That is why a stator that is failing can still produce enough power to the R/R in order for the R/R to rectify the alternating current into direct current and pass that to the regulating function of the R/R. Should the rectifying function receive 70 VAC from 2 phases and 30 VAC from the third phase, the level of output is still higher than 12.8 volts (nominally) and therefore the regulating function will still attempt regulate its output. My alternator on my GL1200 is putting out adequate AC power on two legs, and about 10% power on the third phase...because that leg is shorting to ground within the stator. But the bike still sees 14.2 VDC. It just cannot accept much load (the combination of voltage and current being consumed) and with all the lights on, it will fall to about 12.5 VDC and that will not keep the battery charged. (I PoorBoy'd the bike and left the partially functioning alternator intact.)

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Tue Nov 04, 2014 10:01 am

Does anyone know where to find a Mosfet RR for the 4 cylinder Wings?
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby Scot Thompson » Tue Nov 04, 2014 11:28 am

Shindengen. the GL1200 puts out 360 watts of power from the alternator. Divided by 12 and that yields 30 amps. The LTd and SEI put out more; I can't remember how much. If you find a 30 amp MOSFET it will do fine. the main fuse is 30 amps, right? So, that's the factory limit for the wiring harness. A 50 amp will be overkill, but nothing wrong with that if you keep the fuse specified by Honda.

The supplier up in Oregon provides a nice R/R also, but it is a parallel type of SCR technology. Nothing wrong with that, just a quality replacement for the factory SCR R/R.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby Scot Thompson » Tue Nov 04, 2014 11:30 am

Oops! I meant to say a 50 amp R/R will do fine. I did not mean to say a 50 amp fuse is fine. Use a 30 amp fuse like Honda designed. Scot

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby WingAdmin » Tue Nov 04, 2014 12:21 pm

I agree, Shindengen MOSFET regulator is the way to go.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Tue Nov 04, 2014 12:34 pm

Here is one link I found.
http://roadstercycle.com/
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Tue Nov 04, 2014 4:18 pm

I have just gotten back a GL1200A 85' that I put in a new Stator, Rick's, and used regulator. As I remember the voltage at the battery, at Idle was 12.6, at 2500 RPM also 12.6

Today the readings are Battery Voltage 12.7. When Idling 15.1. At the RR output is 15.8 The Stator connector and Starter Solenoid connector were both replaced with terminals are now fried again.

The AGM battery tests excellent with my Solar digital charging system tester.

Am I looking at a bad RR, or some other problem.
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby wingingit2 » Tue Nov 04, 2014 4:59 pm

I swapped out another used regulator and now I am getting the proper voltage readings. 14.9 at 2500 RPM and 12.5 at Idle.

I guess i will repair the wiring again using heavier wire and try to sell a Shindengen MOSFET regulator.

Any other thoughts are welcome!!
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eacorbett@yahoo.com
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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby eacorbett@yahoo.com » Wed Nov 26, 2014 9:58 am

Having an 85' GL 1200L, yes, things are a lot different but very much the same as all the other 1200's out there, when it comes to the charging systems on these bikes. Again please keep in mind this phrase..... it is not a matter of if but when.......... the charging system is going to fail. My bike is absolutely not exempt from this issue. And of course it failed. I was 1000 miles away from when it did. Thankfully I had trailered it to where I had gone and was able to get it back home. I did an enormous amount of reseatching on this subject and I received the most amount of information on this subject from this very forum. Most of the information ( techinical aspects ) I did not and still do not understand, nor do I need too! I do not care how it works I only need to know what it is I need to do to fix the problem! And as of the time of my failure, this past year, there is not much improvement or upgraded replacements that will prevent this from happening again. However there are many "tricks" posted as to how to help prevent it from happening again. This does not , however, mean that it will not happen again. All I can say is that I did everything within my power to help prevent it from happening again, at least within my life time. Given family history, leaves me with approximately another 9 years, give or take. I literally spent months trying to find better replacement parts. And the only thing I could find better than stock was a mosfet design R/R. After seeing and repairing many melted wires do to the amount of heat this R/R put out I REALLY wanted something that did not put out as much heat. I dealt with ONLY ONE place for everything! It was Rick's motorsports Electircs. As mentioned above. The were very knowledgable and extremely helpful. I purchased a new replacement stator and the above mentioned mosfet design R/R. But I did not stop there. I made sure I got new replacement connectors to go with it. Yes, the very same connectors that EVERYONE says to remove from the bike do to failure or melting from heat. You ask, so why in the heck would you want to put the connectors back in the bike? Since I am the, God only knows what owner of the bike, at least the 5th that I can tell, the wiring had been completely buggerd up from previous owners and the connectors had all ready been removed. I had to have all of that repaired shortly after I purchased the bike. So by the time everything was said and done there were more repairs to the wiring itself than I care to have on the bike. And anyone who has ever had to replace the stator themselves know, you only do it once! It is such an enormous pain the back side that it really isn't worth it to do again. So you want to make sure you do it right the first time. I did not play around, I got extremely serious about this. I replaced EVERYTHING AND I DO MEAN EVERYTHING in the charging system. New stator, mosfet design R/R. AGM battery. and upgraded wire ( 8 gauge, higher quality copper wiring, made in Tn. ). I made my own wire loom for the wiring and seperated it from the original wiring harness. The replacement parts came from Ricks with the wiring upsized from stock to 10 gauge already. Let me tell you that putting 8 gauge wiring into the connectors from Rick's as well was not an easy task by any means but one I felt personally was the correct choice. I have been running this set up for just under a year and I have not had any issues with melting wires or connectors any where on the bike. And I do keep a very close eye on everything. What I believe caused the failure was the bike had sat up for over 7 years without being started or even moved by one of its previous owners. So I knew I was going to have a heck of time a head of me when I bought the bike. Anyway, when I removed the rear cover to access the stator what I found was no surprise. Having been a auto mechanic professionally. Oil build up had dried inside the stator housing preventing an adequate "connection" for a lack of a better phrase or term. Regardless of what caused the actual failure it took it out the entire system, hence replacing the entire system. And yes I did send everything to Ricks to be tested. It fried everything including the AGM battery I had installed when I bought the bike over two years ago. So even though I have read everything in this forum and find very interesting, at least what I could understand of it. Most of it does not help fix the charging issue that these bikes have. Honda dropped the ball big time on these bikes and there isnt much that can be done to stop it from happening again. If you plan on keeping your GL 1200 for any length of time my best advice is to call Ricks or find them on the web get the best parts you can possibly get them replace everything! The wiring, well as I am now an HVAC tech, I got the replacement wire from a 3 phase commercial roof top A/C and heat system that had to be replaced. So I cannot tell you where to wire from.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby pidjones » Mon Dec 01, 2014 1:04 pm

By your description and photo, I feel that you are missing another explaination - metal fatique and brittle fracture due to work-hardening of the copper. As the wire between those poles sees cycling of current, it heats and cools causing the copper to expand and contract thus causing bending in the center where you saw the eventual failure. As the wire became more and more stiffened due to the aligning of rows of atoms causing crystalization and embrittlement, it finally began to seperate and cause the arc sputtering you obsereved evidence of. A machine that I work on suffers asimilar failure in a 1/4" solid copper RF conductor!

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby flash1942 » Mon Dec 01, 2014 3:16 pm

Scot Thompson wrote:A series regulator will do no good with a permanent magnet alternator. However, you can improve the situation with the R/R on these old wings by using a MOSFET R/R. I the factory SCR, the heat one feels is mostly from the swiching going on internally (in the silicon) that shunts the unused power to ground. This happens on all 3 legs of the output of the alternator to the R/R and that is a good thing as some really cheap designs just shunt one leg to ground to regulate the voltage. This switching consumes some power and it takes some time. When the electrical current is switched to ground, it is wasted and we feel that as heat. In the case of the SCRs on the GL1200s, that amounts to about 66 watts...or about the amount of heat a 60-watt light bulb puts out. That is why the R/R is not all the time. But it is designed to deal with this amount of heat, so they should function for a long time. In a MOSFET R/R, the switching function is vastly quicker than the older SCR design and therefore less power is consumed regulating the voltage level. So more power is available to operate the bike; you still have the same shunting to ground occurring though.

Why the series regulator is not useful for a permanent magnet type of alternator is that in a series regulation design, the magnets on the rotor are electro-magnets that require some input voltage to produce a magnetic field. The more voltage supplied to the electro-magnet, the stronger the magnetic field created. The stronger the magnetic field is, the higher the output of the stator as the magnetic fields pass by the coil windings. No input to the electro-magnets, no output of the stator. This is how the level of power is regulated on a series design. On the GL1200s, the rotor contains permanent magnets that produce a constant magnetic field...always, even at rest. These magnetic fields, when rotating, pass by the stator coils and in doing so, an electrical current is induced. The faster the rotation of the constant strength magnetic field, the higher the level of current created at each coil of the stator. Nothing regulates that except the speed of rotation of the rotor. So, in order to regulate a permanent magnet alternator, the power is shunted to ground and turned into heat.

When the stator component of the alternator starts to "bleed" to ground, on one, two or three of the phases, it is still possible to have some output. Even as the electricity is going to ground. Each of the three legs (the phases) of the stator will produce about 70 VAC, so if, say, a short to ground is consuming 40 volts, there is still 30 VAC being passed to the R/R. That is why a stator that is failing can still produce enough power to the R/R in order for the R/R to rectify the alternating current into direct current and pass that to the regulating function of the R/R. Should the rectifying function receive 70 VAC from 2 phases and 30 VAC from the third phase, the level of output is still higher than 12.8 volts (nominally) and therefore the regulating function will still attempt regulate its output. My alternator on my GL1200 is putting out adequate AC power on two legs, and about 10% power on the third phase...because that leg is shorting to ground within the stator. But the bike still sees 14.2 VDC. It just cannot accept much load (the combination of voltage and current being consumed) and with all the lights on, it will fall to about 12.5 VDC and that will not keep the battery charged. (I PoorBoy'd the bike and left the partially functioning alternator intact.)

I'm somewhat perplexed about your statement on series regulators. It's my understanding that series regulators disconnect the stator once voltage requirements have been satisfied and reconnect when voltage is called for and this happens at many times per minute. Unloading the stator when current demand is low would keep heat down in the windings thus extending it's life. It isn't true voltage regulation as we know it but it seems to be a good way to go. Better than running full output all the time. I am installing a series regulator from Roadster Cycle in my wing and anxious to see the outcome.

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Re: How to Predict Catastrophic GL1200 Stator Failure

Postby nipcat206 » Wed Apr 01, 2015 8:33 am

About 13 yrs ago I did all the hard wiring and soldering suggested at the time and bought an Alternator Tester from Radio Shack,#22-7110. Mounted on the dash I could monitor the output at all times. In 2012 I noticed the lights reading lower voltage output. Read about the Poorboy Conversion. Ordered the parts from Donald Pigot and a used GM alternator from my local garage and did the installation. I read comments that the kit was too expensive for what you got. Not so. I've done things from scratch before. This kit saved a lot of time. The price was OK. Tester lights indicate stable voltage output and no problems yet. Follow the instructions and the conversion process is easy. No more stator problems.




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