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Overall Electrical Woes

  • Thread starter Thread starter 81GS850
  • Start date Start date
unbalanced as in the three phases are unbalanced.. IE two are producing 15 VAC at idle and one is producing 2.5 VAC at idle. I would conclude that this is a failed test based on the link you posted about if it fails at low level, it will only fail worse at high level. That's kind of the assumption I was working on when I was attempting to diagnose at idle and getting various readings at idle.
 
It is a test I guess but not very good one.
Click to expand...
I went and tried it and it isn't as easy as I hoped.

with my home-wound stator , a headlamp hi-beam and a 12v car battery , It is too hard to discern any change in brightness. The loads do not match well enough I suppose. BUT still, there is a voltage drop to look at....
without the stator in series I got 11.79vdc
with a "good"stator in series trying the various legs, I see 10.51vdc across the lamp. That's a 1 .25 volt difference to try and discern a fault with... I would really want a load that matches the R of the stator better.

But I will try it again and "better" if I get a bad stator to play with...
 
81GS850 said:
unbalanced as in the three phases are unbalanced.. IE two are producing 15 VAC at idle and one is producing 2.5 VAC at idle. I would conclude that this is a failed test based on the link you posted about if it fails at low level, it will only fail worse at high level. That's kind of the assumption I was working on when I was attempting to diagnose at idle and getting various readings at idle.
Click to expand...


Given it is an imbalance of 7:1 it is most likely going to be just as bad at 5K RPM. So there is probably little risk changing it.
 
Gorminrider said:
I went and tried it and it isn't as easy as I hoped.

with my home-wound stator , a headlamp hi-beam and a 12v car battery , It is too hard to discern any change in brightness. The loads do not match well enough I suppose. BUT still, there is a voltage drop to look at....
without the stator in series I got 11.79vdc
with a "good"stator in series trying the various legs, I see 10.51vdc across the lamp. That's a 1 .25 volt difference to try and discern a fault with... I would really want a load that matches the R of the stator better.

But I will try it again and "better" if I get a bad stator to play with...
Click to expand...

Part of the problem is knowing what resistance the load will be and how much voltage that corresponds to at the loaded legs.

But at only 12v that is not any better than idling.

The whole point of a stator test is to stress it with a higher voltage than a 12V battery. Although a 12V battery if better than a 3V ohm meter test.

And if you are really interested use a megger...............
 
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very cool tool,posplayer! Reasonable prices too! though I'm a little afraid I could too easily hurt myself or a functioning stator with it :)

Part of the problem is knowing what resistance the load will be and how much voltage that corresponds to at the loaded legs.
Click to expand...
I've wondered about that too. I have always just assumed it's strictly wattage to divide by the "breakdown voltage" of the rectifier and battery (~16.7 volts? ..that is 14.5v + .6 for the silicon involved?)-well, there's something for me to find out...
 
Gorminrider said:
very cool tool,posplayer! Reasonable prices too! though I'm a little afraid I could too easily hurt myself or a functioning stator with it :)


I've wondered about that too. I have always just assumed it's strictly wattage to divide by the "breakdown voltage" of the rectifier and battery (~16.7 volts? ..that is 14.5v + .6 for the silicon involved?)-well, there's something for me to find out...
Click to expand...

16.7V would be a nominal peak if you have a regulator.
If it is a dummy load then it is a voltage divider. The calculations are in Revised Phase B tests in GS Charging Health.
 
...just having a quick look at the pdf downloaded...without pondering the "Manualese" lingo but That has 50 watt dummy load,right? so why not just use some 40 -60 watt household light bulbs? I know that these are intended for 120vac but they actually function at lower voltages too. I've used them on several occassions to set field regulation for 12 and 24 volt alternators.... It's just a matter of finding which are best, I guess.
but ...what I was thinking above is that the stator voltage will not be 60-80 vac across stator legs WHEN it is connected to the R/R and battery in a running bike....that doesn't make sense to me except as Open Voltage reading....but I will just have to find out for myself,eh? It'll be easier than doing the math.

Trouble is, my stator is no longer OEM, having wound it myself -fewer "turns" and larger gauge ...but the principle will be ok as it does charge a battery!
 
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Gorminrider said:
...just having a quick look at the pdf downloaded...without pondering the "Manualese" lingo but That has 50 watt dummy load,right? so why not just use some 40 -60 watt household light bulbs? I know that these are intended for 120vac but they actually function at lower voltages too. I've used them on several occassions to set field regulation for 12 and 24 volt alternators.... It's just a matter of finding which are best, I guess.
but ...what I was thinking above is that the stator voltage will not be 60-80 vac across stator legs WHEN it is connected to the R/R and battery in a running bike....that doesn't make sense to me except as Open Voltage reading....but I will just have to find out for myself,eh? It'll be easier than doing the math.

Trouble is, my stator is no longer OEM, having wound it myself -fewer "turns" and larger gauge ...but the principle will be ok as it does charge a battery!
Click to expand...

Yes you need to so it for yourself. And yes open loop and closed loop are different. And yes a light bulb is a resistive load.
 
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Gorminrider said:
... Trouble is, my stator is no longer OEM, having wound it myself -fewer "turns" and larger gauge ...but the principle will be ok as it does charge a battery!
Click to expand...

The biggest difference with your home-wound stator would be that it won't have quite the voltage at any given engine speed as the OEM stator. On the bike, as long as you keep the engine revved above that break-even point, you will be fine.

.
 
yes indeed,Steve. A little less..My later stators have more windings just because I got neater though I'm not yet sure if more windings is a good thing if it makes them internally hotter too. ... Here is 2500 rpm with 36.5vac showing on the Multimeter when Bike Voltage is apparently 14.2 VDC....if I can trust my meter. Does about 60vac (and brighter too! )when revved up to 5000RPM.

...actually,this stator may burn up at the connecting wires because they are just plain plastic covered wire only good to what? 100C? Not high heat,anyways.
I've seen lots of brittleness and shrinkage on the ones I was replacing so I'm crossing my fingers on this one.

View attachment 36144
 
Gorminrider said:
yes indeed,Steve. A little less..My later stators have more windings just because I got neater though I'm not yet sure if more windings is a good thing if it makes them internally hotter too. ... Here is 2500 rpm with 36.5vac showing on the Multimeter when Bike Voltage is apparently 14.2 VDC....if I can trust my meter. Does about 60vac (and brighter too! )when revved up to 5000RPM.

...actually,this stator may burn up at the connecting wires because they are just plain plastic covered wire only good to what? 100C? Not high heat,anyways.
I've seen lots of brittleness and shrinkage on the ones I was replacing so I'm crossing my fingers on this one.

View attachment 36144
Click to expand...

Not really sure what you are doing there. If closed circuit, the stator legs are going to be clamped at the 14.5V battery voltage plus the 1.1V forward drops of the full wave rectifier (shunt R/R).

Now is it is open loop using the dummy load, for a relatively high resistance compared to the stator (say 10 ohms per leg) you will get a voltage output proportional to RPM because with 10 ohms you can saturate the rotor.

120V light bulbs are fine for loads if you have the H/W laying around. My load tester is much smaller and much less likely get get broken; cost $20. The bulb brightness is a problematic measure of voltage balance. Just use the VAC measurement. It is much more accurate.

If you have read the Revised Phase B pdf, you would see that with 10 ohms the open loop voltage is only 5-10% reduced from pure open circuit tests.

So it is not clear what you are trying to do.

A dummy load test at RPM using light bulbs?

Static test at zero RPM?

Loaded test with R/R and a battery?
 
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Not really sure what you are doing there.
Click to expand...
I'm just fooling around.. I don't always have a multimeter handy so If I have a test that uses a mere lightbulb, that seems useful to me. Plus, it glows, costs nothing and is always handy, where a dummy load with heatsinks does not.
If closed circuit, the stator legs are going to be clamped at the 14.5V battery voltage plus the 1.1V forward drops of the full wave rectifier (shunt R/R).
Click to expand...
yes, that's what I surmised but it seems difficult to test with a cheapo multimeter. No matter, my simple universe just wants light, not numbers.
 
Gorminrider said:
I'm just fooling around.. I don't always have a multimeter handy so If I have a test that uses a mere lightbulb, that seems useful to me. Plus, it glows, costs nothing and is always handy, where a dummy load with heatsinks does not.
yes, that's what I surmised but it seems difficult to test with a cheapo multimeter. No matter, my simple universe just wants light, not numbers.
Click to expand...


Just fooling around?? OK I understand that.

Yes light bulbs could serve as a dummy load, much like power load resistors, however this is still not a zero RPM test.

I guess you can get some sort of crude measurement of balance from light intensity, but as a substitute for a VOM it is not even a comparison.

As far has being handy...... So you carry around 3 light bulbs and sockets and have no room for a VOM? I think a $5 Harbor Freight VOM would be much preferable to a bag or light bulbs.

As mentioned in the Revised phase B testing there are various failure mechanisms and they can be power, temperature and voltage dependent. So having different stressing tests is not bad. The best is the leg to ground test at 5K RPM. A loaded test is good if have an intermittent thermally related problem. All require 5K RPM
 
So you carry around 3 light bulbs and sockets and have no room for a VOM? I think a $5 Harbor Freight VOM would be much preferable to a bag or light bulbs.
Click to expand...
I would "borrow" lightbulbs from the motel I was stuck in... :) or, sometimes I happen upon other bikes with charging problems. It'd be nice to whip up a fast indicator of stator output .
 
Just an update.. Took the stator to work and hipotted it.. Didn't short to ground till 1000V so that didn't give me a warm fuzzy that was the issue. I have a new one coming anyways, especially since I fried the stator doing the hi pot. Oops...

Checked the r/r again and one of the diodes is bad. I'm thinking a bad diode and bad stator leg is why the bike isn't charging. I'll keep everyone posted.
 
Generally you probably will not see over 200 volts with the series r/r when it goes open circuit.
if you shorted a diode it could be you would have shorted a stator leg at the same time eventually braking down the stator insulation.
 
Well the hipot goes from 250-500-100V. I tried the first two first. It musta just been going out because i swear I checked it the first time and the diodes were fine. Oh well... my other r/r checked out.
 
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