VRR Stator investigation

[Normk]

A friend helped to do some testing of my 1979 GS850G which might be of interest. Review of the Stator Papers and much other information regarding permanent magnet alternators indicates that there will be no ground breaking developments here but something may be useful or interesting. I try not to predicate my posting on a desire to appear better informed or to avoid the risk of being in error.

We used my oscilloscope to measure AC wave form and voltage from two pairs of stator legs, a Hall Effect (clamp on) ammeter on the VRR ground wire, voltmeter across battery, and some loads.

If someone can expand on or interpret results further/advance theory or what ever comment, it would be appreciated.

The bike has original wiring with what appears to be the original or original pattern VRR. Modifications are bar heaters and HID headlight, both of which can be switched off.

The first scope wave form was very strange until one of us suspected that it might be caused by the HID unit which was switched off, resulting in a more standard stator wave form. Sorry but photos and posting them are too much trouble. Regardless, the waveforms were consistent and our intent was to measure voltage rather than to interpret wave forms.

First test, stator open circuit/ stator wires unplugged and measured voltage between two pairs of legs:

Idle 1,500 RPM -80 volts AC
4,000 RPM -250 volts AC

Second test of stator voltage, original Suzuki VRR & stator leads reconnected:

Idle- 70 volts AC
4,000 RPM - 150 Volts AC

DC output (battery) 14.5 volts

Full load current from either VRR was 13.4 amps. measured in the VRR's ground wire. The ground wire was selected because this circuit will carry all rectified current from the VRR, regardless of whether the regulation is by load/Zenor type, or clipper/modulated output current.

Third test of stator voltage, Yamaha VRR & stator leads connected:

Idle- 20 volts AC
4,000 RPM - 20 Volts AC

DC output (battery) 14.4 volts

Today the alternator output was 13.4 amps. maximum although it has achieved 14 amps. on previous occasions.

OK, so you noticed it too!

"How can the stator voltage differ between the use of the two VRR units?"

Faraday's equation:

E = BLv

Where:
E = Generator EMP (Voltage)
B= Flux density (strength of the magnetic field)
L= Length of the conductor within the magnetic field
v= Velocity/speed relative

Lorentz force if memory served .....

So how can "E" differ when "BLv" are the same unless there is some action within the exit circuit (VRR)?

I need to go back to review the complete set-up of the test because something seems to be amiss. Any ideas?

A high resistance in one stator leg or leg connection could have pushed up voltage but that should have resulted in a reduction in the output current which was not noted.

Maybe there's something obvious I'm missing??

[Graham]

E = Generator EMP (Voltage)
B= Flux density (strength of the magnetic field)
L= Length of the conductor within the magnetic field
v= Velocity/speed relative



I’m not understanding what the use of E=BLv has to do with VRR output? Why does simple power generation get so complicated?
Are you trying to point out that the Suzuki and Yamaha stator voltage are different but the VRR output is nearly the same and asking why? If so your missing AC amps from stators. Stator voltage doesn’t equal VRR wattage (volts and amps).
Maybe I’m just missing your point all together.

FYI; the stator papers just over complicate stator and regulator/rectifier testing.

[Normk]

Power generation does not need to be complicated, the understanding of the dynamics simply become so as one delves deeper. It is not a condition which I am creating so don't appreciate being told off.

Clearly, E=BLv relates to VRR output because it is the source energy. I cannot reliably measure the AC current in the stator legs under load because of the frequency involved which is outside of the certification range of my meter.

I will take this to another web group as the message received was not positive. I was simply trying to learn something and thought it might be useful/interesting to someone else.

[Steve]

I find your open-circuit voltages to be a bit interesting.

Most of us have found something in the range of 20-40 VAC at idle, then about 75-90 VAC at 5000 RPM. Just wondering how you got 250 VAC.

Or was that maybe peak-to-peak voltage on the scope? I am only using a simple Fluke 77 meter, which is similar to what is used in all of the service manuals.

I am also wondering about your selection of Yamaha R/R. I know that some of the bikes have alternators with variable-field windings, not permanent magnets. Just wanting to make sure you have the correct R/R for the GS setup.

Some time ago, Posplayr did a rather extensive analysis of the charging system using a scope. Might take a look at some of those posts to see if they jive with what you were just seeing.

.

[twotimeGSr]

Formula

Power generation does not need to be complicated, the understanding of the dynamics simply become so as one delves deeper. It is not a condition which I am creating so don't appreciate being told off.

Clearly, E=BLv relates to VRR output because it is the source energy. I cannot reliably measure the AC current in the stator legs under load because of the frequency involved which is outside of the certification range of my meter.

I will take this to another web group as the message received was not positive. I was simply trying to learn something and thought it might be useful/interesting to someone else.

NORMK: I too have a 79 850 and will have to deal with this issue sooner or later.. please give this forum a chance to respond over the weekend. I am no electrical guru... but If I get your drift.. you are using the formula to basically say the two units should produce the same output as the variables are the same..? The numbers seem to be pretty far apart.. are you certain the magnetic field strength is the same between the units?

I would like to see this answered too.

There are great folks on this forum that help each other with many "non-standard GSR methods".. heck I just had one member volunteer to help me change the front wheel bearings on my wife's Accord... had a great time and met a new friend in the process.

Hope you get the results you are looking for.

tp

[Normk]

Steve, thanks for the suggestion regarding the previous oscilloscope work on the system. Any chance you have a link?

We were using my "PK Precision 20 MHz Storage Oscilloscope" in case the specific scope has a bearing on someone's interpretation of the measured values. My life is not at risk because these values appear not to make sense but am curious as these kinds of anomolies usually reveal that some error has been made. I re-did the measurements and since they were taken off two stator legs, one to each scope channel, connection problems should not have been likely.

The second VRR was given by a friend with some other electrical and electronic bits from what I understood was a liquid cooled Yamaha cruiser (650?) but he is not sure. There is no information as to maker on the VRR but would be pleased to post a photo if someone feels that they may be able to identify.

The voltages from the stator were peak to peak with the scope. The output from the VRR units were taken from the ground wire by means of my Mac Tools clamp-on ammeter and DC voltages with my Mac Tools digital multimeter. Again, if someone has an interest in the models, I can post.

I did not attempt to measure the stator leg currents as there is no assurance that the measurements will be accurate, given the frequency range compared with my meter's design specifications. Should really review that though....

What I am hoping is to find that I am off base in terms of some aspect of understanding so that something valuable can be learned. Finding out thatI am correct results in no learning opportunity.

To review my concern:

1) The same bike's stator, rotor & wiring were used in comparing the values measured.

2) The only change was to unplug the "original" Suzuki VRR and to jumper in the "Yamaha" VRR.

3) In both VRR tests, the same output current and nearly identical voltages were in effect.

4) It did not seem practical to measure stator current but this was inferred as being the same because the same alternator was producing the same DC output.

5) The question, given that the same conditions according to what was measured and what is understood regarding generator theory, is; "How can stator voltage be different when the two VRR are affecting the system?"

Ever have your wife give you "the look" and then tell you how wrong you are despite that you were sure....? That's kind of where I am right now.

Norm

NORMK: I too have a 79 850 and will have to deal with this issue sooner or later.. please give this forum a chance to respond over the weekend. I am no electrical guru... but If I get your drift.. you are using the formula to basically say the two units should produce the same output as the variables are the same..? The numbers seem to be pretty far apart.. are you certain the magnetic field strength is the same between the units?

I would like to see this answered too.

There are great folks on this forum that help each other with many "non-standard GSR methods".. heck I just had one member volunteer to help me change the front wheel bearings on my wife's Accord... had a great time and met a new friend in the process.

Hope you get the results you are looking for.

tp

[Normk]

tp, you have one of Suzie's sisters then?

You have nailed the issue exactly! What I expect is that some aspect of measuring has been done in error on my part. What I hope is that the figures and method are correct and that someone will explain, in a manner which I can understand, what aspect I fail to understand. That will be one of those big, "Ah, ha!" moments.

Same charging system excepting for swapping the two VRR units, so B, L, & v must be the same as these were in effect during both tests. So, why is E different?

I spend a huge amount of time helping others where I can and usually receive some sort of reciprocation in terms of help, willingness to investigate something for which more data is desired, or simply good fellowship and respect. The opportunity to learn, through investigation or attempting to help someone else, is the pay-off.

Norm

NORMK: I too have a 79 850 and will have to deal with this issue sooner or later.. please give this forum a chance to respond over the weekend. I am no electrical guru... but If I get your drift.. you are using the formula to basically say the two units should produce the same output as the variables are the same..? The numbers seem to be pretty far apart.. are you certain the magnetic field strength is the same between the units?

I would like to see this answered too.

There are great folks on this forum that help each other with many "non-standard GSR methods".. heck I just had one member volunteer to help me change the front wheel bearings on my wife's Accord... had a great time and met a new friend in the process.

Hope you get the results you are looking for.

tp

[posplayr]

unfortunately all of the uploaded pictures over a 3 year period were lost

http://www.thegsresources.com/_forum/showpost.php?p=967419&postcount=81

[bakalorz]

<snip>
To review my concern:

1) The same bike's stator, rotor & wiring were used in comparing the values measured.

2) The only change was to unplug the "original" Suzuki VRR and to jumper in the "Yamaha" VRR.

3) In both VRR tests, the same output current and nearly identical voltages were in effect.

4) It did not seem practical to measure stator current but this was inferred as being the same because the same alternator was producing the same DC output.

5) The question, given that the same conditions according to what was measured and what is understood regarding generator theory, is; "How can stator voltage be different when the two VRR are affecting the system?"

Ever have your wife give you "the look" and then tell you how wrong you are despite that you were sure....? That's kind of where I am right now.

Norm

I only have a couple minutes, and this is off the cuff, and I want to eventually re-read to make sure I haven't missed anything, but a quick comment as food for thought.

The Suzuki R/Rs on these model bikes only regulate (shunt) either one or two phases depending on the model.

Most of the aftermarket R/Rs regulate all three phases.

I believe you were only looking at one phase ... blind luck could make it an unregulated one for the Suzuki R/R.
Alternatively, even if the phase in both tests were regulated ones, the control circuit on the Suzuki regulator is probably going to have to shunt the phases it does shunt harder to give overall equal output to one which is balanced among all three phases (does this explanation make sense to you?)

[bakalorz]

I only have a couple minutes, and this is off the cuff, and I want to eventually re-read to make sure I haven't missed anything, but a quick comment as food for thought.

The Suzuki R/Rs on these model bikes only regulate (shunt) either one or two phases depending on the model.

Most of the aftermarket R/Rs regulate all three phases.

I believe you were only looking at one phase ... blind luck could make it an unregulated one for the Suzuki R/R.
Alternatively, even if the phase in both tests were regulated ones, the control circuit on the Suzuki regulator is probably going to have to shunt the phases it does shunt harder to give overall equal output to one which is balanced among all three phases (does this explanation make sense to you?)

Also, one other possibly salient point.

Everyone tends to assume that the charging currents are DC.
They really aren't if looked at in any depth.

I had a pretty big argument with posplayer about it in this linked thread.

the thread also has a BONUS ... a fair # of posplayers scope plots mentioned above were referenced in it and they still showed up there ...

but anyway the main point is that depending what you were measuring where with the hall effect sensor (and how your meter averages or RMSes it etc), the fact that there is a HUGE amount of AC riding the DC average in some current paths could make some of your hall effect sensor readings not really be what they seem to be.

[Normk]

You may have answered the question regarding that unregulated leg but also will have to think about this further. I had channel one on one pair and two anther but will try to make time tomorrow to scope the three combinations in case the values are different. I hadn't thought about the effect of one unregulated leg....this is already worth while as there's something more can be checked

Too bad this isn't likely to lead to anything practical but still learning...

I do wonder, however, if the original VRR encourages high stator voltage then a replacement which doesn't might be less prone to causing failure of the stator winding insulation?

That is going another direction as we used 120 volts AC limited by a 50 Watt trouble light bulb to test automotive stators for grounds. The automotive alternator stators have only the lacquer on the wires as insulation as they lack the potting compound used on bike stators. If they don't suffer from 120 volts then I think it might be hard to make the above case.

Another aspect of that is the old "Tote-a-Volt" and alternator kits of that type would isolate the alternator from the regulator and vehicle electrical system, run alternator output to the field (rotor). They would produce 80-100 volts DC to operate brush type power tools and survived reasonably well. They did make a lot of heat from hysterisis loss but that isn't a voltage effect.


By referring to the charging currents as not DC I assume that you are talking about the ripple wave form?

Some bike alternators make a bit of AC on the VRR output but (will go back and recheck) I must have checked this bike for AC current in the VRR DC output as this is a common test to identify a shorted diode.

When you have time it would interesting to hear your point of view.

I only have a couple minutes, and this is off the cuff, and I want to eventually re-read to make sure I haven't missed anything, but a quick comment as food for thought.

The Suzuki R/Rs on these model bikes only regulate (shunt) either one or two phases depending on the model.

Most of the aftermarket R/Rs regulate all three phases.

I believe you were only looking at one phase ... blind luck could make it an unregulated one for the Suzuki R/R.
Alternatively, even if the phase in both tests were regulated ones, the control circuit on the Suzuki regulator is probably going to have to shunt the phases it does shunt harder to give overall equal output to one which is balanced among all three phases (does this explanation make sense to you?)

[Graham]

Power generation does not need to be complicated, the understanding of the dynamics simply become so as one delves deeper. It is not a condition which I am creating so don't appreciate being told off.

Clearly, E=BLv relates to VRR output because it is the source energy. I cannot reliably measure the AC current in the stator legs under load because of the frequency involved which is outside of the certification range of my meter.

I will take this to another web group as the message received was not positive. I was simply trying to learn something and thought it might be useful/interesting to someone else.

Didn’t mean to sound so harsh.

[Normk]

Wow! Just got into that earlier thread with waveforms for which you provided the link. (Sorry didn't see the link before answering)

My spare time reading and re-reading will be on that one for some time. Very much appreciated as haven't seen a decent appreciation of the subject before. It looks like I need to go back and pay more attention to the waveforms also rather than simply attending to the peak voltages. My scope isn't even close to the one referenced either so may not be able to read effectively.

Exciting stuff!

[bakalorz]

By referring to the charging currents as not DC I assume that you are talking about the ripple wave form?

It's WAY more than just ripple.

read that thread I linked above, one of posplayers scope plots shows it well, its the one I marked up.

the battery charging current is an average of 2 amps dc ...
...
In reality, there is current going into the battery of ~ 10 amps (when not shunting)
alternating with current going out of ~ 10 amps .... (while shunting, when the battery is supplying the loads on the bike)

the in time is longer than the out time leading to an average of 2 amps in ...

read the whole thread (at least the parts between pos and me) if the above doesn't clear it up

[bakalorz]

Wow! Just got into that earlier thread with waveforms for which you provided the link. (Sorry didn't see the link before answering)

My spare time reading and re-reading will be on that one for some time. Very much appreciated as haven't seen a decent appreciation of the subject before. It looks like I need to go back and pay more attention to the waveforms also rather than simply attending to the peak voltages. My scope isn't even close to the one referenced either so may not be able to read effectively.

Exciting stuff!

You must have posted while I was composing my msg...

I don't think you need a whizbang scope to see what is going on ...
If you don't have a current probe, you should still be able to view the currents using an appropriate piece of wire as a shunt and measuring the voltage across it. (don't coil the wire for the shunt up though ... )