Rectifier/Regulator replacement list

[posplayr]

The stator is not included in your flow diagram.

It's in this one.

http://www.thegsresources.com/_forum/showpost.php?p=1195034&postcount=41

[Matchless]

Apologies Jim, I will leave the exact details to you as you are the GSR official guru on this!

But just one question and comment that I think is relevant. You pertinantly mention that when the R/R is crowbarred the current that is then sent back to the stator will cause more heat in the stator. The question now, is that, insignificantly more heat, a little more, significantly more heat, or dangerously more heat? Has anyone measured this in practice?

If the stator is already puttting out maximum AC current it is already running hot significantly more heat will surely kill the stator. So on later bikes with FET R/R by the OEM, has this been addressed in any way?

I was under the impression that the stator could handle its own current easily whether it is dissipated in the load or shunted back onto itself. If the stator is in a poor shape that is another matter.

In countries where bikes have a light switch and it is not law to have your lights on, it has not given raise to higher stator and/or R/R failures and then I am refering to all makes of bikes using this same system for the last 30 years or more.

Just a stone into the bush!

[salty_monk]

From stock the bikes with the light switch (at least in the US) are wired so that one leg of the stator is open with the light switched off meaning it's output drops off significantly.

Dan

[Matchless]

Dan,
That is what we have over here as well. I think Suzuki was not the only manufacturer that did that at the time.

Around that time some R/R's only regulated on 1 or 2 phases and the 3rd phase was then switched in or out as less components and lower current rated ones were smaller and cheaper and kept the cost of the R/R down. That was the reason for Suzuki using different colour wires from the stator, as you would not like to switch out the only regulated phase! I think nowadays all R/R's regulate on all 3 phases.

As far as stators go, the copper wire insulation can and does break down with age and heat as well as exposure to chemicals such as hot oil etc. over time. Nowadays copper wire with very durable insulation, that is heat resistant, chemical resistant and self healing is available. Much better sealing epoxy is available. Some rewinds or aftermarket may be using low quality wire not designed to work under these conditions or the rewind did not allow for preseating, expansion and contraction or the epoxy sealing was not done properly or substandard epoxy or enamel was used. We will never really know and may blame the R/R or some other culprit.
In actual fact the stator allows for more physical variables than the R/R and may in some cases be the cause of a charging system failure and not the victim!

So what I am saying is that if you upgrade your R/R and replace a battery, also give serious thought to replacing your stator with a high quality rewind or new replacement. A used one may already be close to its last days and/or of inferior quality. We constantly refer to "that 30 year old wiring", but what about "that 30 year old stator"!

Treat that new FET 50A to a brand new stator, comply to Jim's wiring recommendations and you will have a charging system that you can forget about!
Keep well!

[posplayr]

Apologies Jim, I will leave the exact details to you as you are the GSR official guru on this!

But just one question and comment that I think is relevant. You pertinantly mention that when the R/R is crowbarred the current that is then sent back to the stator will cause more heat in the stator. The question now, is that, insignificantly more heat, a little more, significantly more heat, or dangerously more heat? Has anyone measured this in practice?

I worked up a simplified schematic but want to run it by a guy here at work. I'm making some simplifying assumption but the way it looks the stator current doubles when the crowbar is in effect.

If I have my number right, basically there is about 1.4 ohms in the stator leg to stator leg resistance and about 1.2 ohms in the load (14.5V/12.0A). These are both basically in series, so total resistance is 1.4+1.2=2.6 ohms. After the crow bar that drops to 1.4 ohms so the current would go up in proportion.

The charging system is designed to largely match the demand and the less it has to "regulate" (i.e. crow bar the better)

Here is an approximate analysis that captures the essence of what happens when the stator is crow bared during regulation.

http://www.posplayr.100megsfree3.com/FH012AA_Charging/charging.pdf

If the stator is already puttting out maximum AC current it is already running hot significantly more heat will surely kill the stator. So on later bikes with FET R/R by the OEM, has this been addressed in any way?

I was under the impression that the stator could handle its own current easily whether it is dissipated in the load or shunted back onto itself. If the stator is in a poor shape that is another matter.

!

The stator will not burn up if you provide a load to suck up the power it generates. (i.e like lights on at highway speeds). If not and the R/R has to regulate then the current goes up.

In countries where bikes have a light switch and it is not law to have your lights on, it has not given raise to higher stator and/or R/R failures and then I am refering to all makes of bikes using this same system for the last 30 years or more.

Just a stone into the bush!

Those bikes open the stator winding effectively killing the power (i.e. no current from that leg).

[posplayr]

Dan,

As far as stators go, the copper wire insulation can and does break down with age and heat as well as exposure to chemicals such as hot oil etc. over time. Nowadays copper wire with very durable insulation, that is heat resistant, chemical resistant and self healing is available. Much better sealing epoxy is available. Some rewinds or aftermarket may be using low quality wire not designed to work under these conditions or the rewind did not allow for preseating, expansion and contraction or the epoxy sealing was not done properly or substandard epoxy or enamel was used. We will never really know and may blame the R/R or some other culprit.
In actual fact the stator allows for more physical variables than the R/R and may in some cases be the cause of a charging system failure and not the victim!

Exactly, while we think of the stator as an electical component, we should treat it more like our tires.

If it is old(tires/Stator) --- then it is probably stressed and cracking

If we run it hard(tires/stator) then it is nearly worn out (insulation got hot due to highertemps and higher current output)

All it takes is one small (blow out/Short) to ruin your day

[Matchless]

Those bikes open the stator winding effectively killing the power (i.e. no current from that leg).

Jim,
I looked at some Suzuki wiring diagrams and it seems as if around 1984/85 Suzuki dropped the idea of diverting a phase via the headlamp switch. As far as I know it has not been reintroduced. Three yellow wires from stator usually proves that.

I am quite confident in my belief that the stator on a bike with headlight always on and one with switched headlight was the same or similar from an electrical point of view.
In those days the stator could already handle all the current generated and could only provide it at maximum rated output of say 15 A. It cannot act like a battery with can supply hundreds of amps if crowbarred even if of very low capacity.

At that time the crowbar or shunt (R/R)was the weak part and acted like a fuse if handling large currents for long times at close to or exceeding its rated capacity and failed.

Does it really matter whether a load draws say 15 Amp from the stator or if a crowbar or shunt draws 15 Amp from the same stator?

The voltage, current, frequency is in a permanant dynamic state always fluctuating greatly and we have AC voltage and current then that is full waved rectified voltage providing the DC voltage and current, again always fluctuating, changing continuously as well as the AC frequency. It is also well known that some electrical components can be driven beyond their rated capacity by pulsing them rapidly instead of powering them steadily.

You may recall the time when old aircraft generators were used as welders? Amazing how thin copper windings can provide current heavy enough to melt a screwdriver!

Finally we cannot have more current than we originally generated returning to the alternator, only less, as some is absorbed and dissipated as heat in the load (lights, battery etc) So if the lights do not use it, the crowbar is going to use it, heat up and dissipate the heat via its well designed large cooling fins.

This is just a discussion to tie in with all your findings and analysis to date. I am just approaching my view on it from another angle.
Keep well.

[posplayr]

Jim,
I looked at some Suzuki wiring diagrams and it seems as if around 1984/85 Suzuki dropped the idea of diverting a phase via the headlamp switch. As far as I know it has not been reintroduced. Three yellow wires from stator usually proves that.

I am quite confident in my belief that the stator on a bike with headlight always on and one with switched headlight was the same or similar from an electrical point of view.
.

Andre,

If we are talking about a ganged headlamp switch that opens the connection between the stator and the R/R when the lights are off, this clearly has an effect on the circuit. It opens up one of the stator legs so no stator current flows from that leg. The other two legs still flow, but there is a lot of distortion in the rectifier due to the imbalance in the stator.

I don't know why Suzuki got rid of it for sure, but running a high voltage stator wire to the handle bar switch is such a bad idea, I can imagine that the practice eventually died out .

In those days the stator could already handle all the current generated and could only provide it at maximum rated output of say 15 A. It cannot act like a battery with can supply hundreds of amps if crowbarred even if of very low capacity.

At that time the crowbar or shunt (R/R)was the weak part and acted like a fuse if handling large currents for long times at close to or exceeding its rated capacity and failed.

Does it really matter whether a load draws say 15 Amp from the stator or if a crowbar or shunt draws 15 Amp from the same stator?

.

The circuits I drew in the link before are approximation of the 3 phase AC and the full wave rectification, how ever the Thevenin equivalent circuit of a voltage source in series with a resistance is a very good representation of what is going on in the stator. The two primary ways to embellish it would be to add a series inductance and series magnetization curve. But but neither in anyway change the fact that the stator is a voltage source. The current through that voltage source is a function of it's own resistance and the series load resistance. This is fundamental and is true for all series would motors and generators.

http://www.posplayr.100megsfree3.com/FH012AA_Charging/charging.pdf

It is also well known that some electrical components can be driven beyond their rated capacity by pulsing them rapidly instead of powering them steadily.

You may recall the time when old aircraft generators were used as welders? Amazing how thin copper windings can provide current heavy enough to melt a screwdriver!

.

Agree that is why the stator survives the increased current during the crow barring. However running at high RPM for sustained periods causes more stress on the stator because the R/R is shunting at a higher duty cycle then it would at lower RPM.

Finally we cannot have more current than we originally generated returning to the alternator, only less, as some is absorbed and dissipated as heat in the load (lights, battery etc) So if the lights do not use it, the crowbar is going to use it, heat up and dissipate the heat via its well designed large cooling fins.

.

You need to rethink this underlined statement. You are confusing current and power. Current flows in a loop and is the same all around the loop. Power is dissipated due to resistance, but current has to flow in a loop.

Also when being crow-bared it is as if you put a screwdriver across two stator windings. For the voltage being produced at that phase in the cycle the only thing limiting the current is the stator resistance, so the current increases.

This analogy is actually very accurate in describing the current flow induced in the stator windings and how a current will only flow in a circuit. I was discussing metal fatigue properties as it relates to "Life Consumption Monitoring" as a foundational element of Diagnostic and Prognostic systems with our local (down the hall from me) Harvard Phd in Theoretical Physics. I got a refresher in basic atom/electron theory and what distinguishes ductile from non ductile materials. I also got a smattering of astrophysics and string theory among other topic. Anyway, following the discussion with Dr. Bob, I needed to draw an explanation of current flow and power dissipation for the “GS Charging Contest”.

http://www.thegsresources.com/_forum/showthread.php?t=157589

I developed the circuit analogy below which is like a hydraulic analogy as there is a tube involved, but it also clearly shows the circular current flow and how power is dissipated heat due to resistance and is NOT somehow the consumption of current. In this analogy the push (voltage) comes from the sweeping of the magnet past the balls. For our discussion there would be two resistances in the tube, one for the stator windings (1.4 ohms) and the other the load (1.2 Ohms). When the load resistance is removed (i.e. the stator is crow bared), the same push causes the balls to go faster (i.e. more current) because there is less resistance.

http://www.thegsresources.com/_forum/showpost.php?p=1195019&postcount=40

Jim

[posplayr]

Andre,

Here is a simple DC motor model. A generator or motor really act the same it just depends on whether you put in mechanical power or electrical power.

http://www.ecircuitcenter.com/Circuits/dc_motor_model/DCmotor_model.htm

If you simplify to a DC analysis (simplification of the 3 phase AC and rectification) then the equations reduce to the ones I'm using.

In the case of the link V_amp would be an applied voltage (which the stator produces voltage) so the stators "internal" voltage is V_emf. Since we are doing DC analysis the LdI/dt term is set to zeo and we simply have

Vemf = R_motor* I_1 .

For the GS case we have a separate resistance in the load (I also replaced R_motor with R_stator) so we are really left with:

V_emf = (R_stator+R_load)*I_stator.

which yeilds:

I_stator = V_emf/(R_stator+R_load)

So when the R_load changes it changes the current flow.

If R_load is very large (like when the left hand switch has the lights off) then I_stator goes to zero.

If R_load is zero (i.e a direct short) then the only limit to the curent is the resistance of the stator itself.

When the R_load is connected it is the series resistance of R_load and R_stator which limits current.



Hope this helps,

Jim

BTW, For anybody else trying to follow this link; back EMF is essentially what I describe above as a motor acting like a generator. When a motor spins up due to an applied voltage, the motor generates it's own voltage that increases to almost equal the the applied terminal voltage (V_amp). In steady state, the only difference in the back EMF voltage and the applied terminal voltage is an amount that is required to get enough current to produce suffcient torque to overcome frictional forces.

So as an example, if you could leave your starter motor engaged, then as the engine turned teh stater motor over it would charge your battery. Like wise, if the motor is not turning over and you apply voltage to teh starter, it will crank over the motor and the engine.

So depending upon the efficencies, electrical power can be converted to mechanical (as in a motor) or mechanical to electical (as in a generator) in the same device. The difficulties are in the actual implementations of controlling/regulationg the electrical power out making a starter capable of running at low speed for cranking but also at 10K RPM (engine speed).

[salty_monk]

I think I'm getting it.... Thanks Jim.
You are testing my A level physics to it's extents now!!

[Matchless]

Well done Jim! You still know your stuff! I am very rusty as you probably noticed and have forgotten most of the theory due to wear and tear. Although I can still recall the story of Micro-Farad and Milli-amp quite well!

Basically we were trying to figure out if Salty's stator will run warmer if he uses a FET R/R and how much warmer.

Jim if you figure it out, as I think you will, it would be usefull info to all of us myself included.

Salty, apologies for us fooling around a bit, and I think you will agree Jim gets full marks for going all the way when it comes to his passions!

Jim has already contributed a wealth of detailed information to the forum members, which I am sure has been read and used by many.

[posplayr]

Well done Jim! You still know your stuff! I am very rusty as you probably noticed and have forgotten most of the theory due to wear and tear. Although I can still recall the story of Micro-Farad and Milli-amp quite well!

Basically we were trying to figure out if Salty's stator will run warmer if he uses a FET R/R and how much warmer.

Jim if you figure it out, as I think you will, it would be usefull info to all of us myself included.

Salty, apologies for us fooling around a bit, and I think you will agree Jim gets full marks for going all the way when it comes to his passions!

Jim has already contributed a wealth of detailed information to the forum members, which I am sure has been read and used by many.

Thanks Andre,
I've done some preliminary calcs but dont want to mis report anything. I'll look at this tonite
Jim

[salty_monk]

It's all useful stuff. I have a very basic understanding of most of it from my College (UK college 16yr - 18yrs, we specialise in 3 subjects at that stage) Physics but some of it goes over my head!

I guess as Jim says - we should probably be ready to replace stator's more often than we do...

By the way... won't state of charge of the battery also have an impact on heat generated as some of that current would be used up by the battery to charge it if not fully charged wouldn't it?

Dan

[posplayr]

It's all useful stuff. I have a very basic understanding of most of it from my College (UK college 16yr - 18yrs, we specialise in 3 subjects at that stage) Physics but some of it goes over my head!

I guess as Jim says - we should probably be ready to replace stator's more often than we do...

By the way... won't state of charge of the battery also have an impact on heat generated as some of that current would be used up by the battery to charge it if not fully charged wouldn't it?

Dan

Dan,
Ironically the more load the GS/Battery takes the less that has to be crow-bared to the stator when the voltage gets too high.
Jim

[salty_monk]

That was my point... so in a way a flat battery is good!