Why Unloaded Stator tests are BAD.

[tkent02]

How about strapping an AC voltmeter to the handlebars and going for a long ride? Hook the meter between any two stator leads for a while, then another pair, then the other pair.
Seems like you would see any problems this way, whether temperature related, or load related or anything else. Maybe having a DC meter hooked across the battery at the same time would be helpful as well.
I dunno, in all the GSes that have been through here, I've never had a stator failure other than one that was clearly bad when I bought the bike.

[posplayr]

How about strapping an AC voltmeter to the handlebars and going for a long ride? Hook the meter between any two stator leads for a while, then another pair, then the other pair.
Seems like you would see any problems this way, whether temperature related, or load related or anything else. Maybe having a DC meter hooked across the battery at the same time would be helpful as well.
I dunno, in all the GSes that have been through here, I've never had a stator failure other than one that was clearly bad when I bought the bike.

Kent,
Other than the difficulty of the logistics, the main issue is that you still can not isolate absolutely between a R/R and the stator. When the R/R is disconnected then everything is unloaded. So the solution is to have an external dummy load in order to perform loaded tests.
If there is a hard failure then, there is no need as the unloaded tests will confirm failure, just not a good stator.
Jim

[salty_monk]

I'm all for a good debate about anything but there is no need for this to get personal.
Calls of incompetence etc. It's nasty.

At the end of the day this is a forum where friendly people give friendly advice. You have to do your own research & make up your own mind if you follow it.

Bakolorz it's great that you have technical knowledge to help others but you can disagree & phrase your posts a little better without getting personal.

Stators have not been a real issue for me yet either... touch wood!

Dan

[Graham]

How are loaded tests going to confirm a good stator? How much current is a stator going to put out under load? Does the manufacture provide that information? If not where does someone get that information?

Wouldn’t a test under load show the current used by the load and not the maximum safe output current of the stator? When someone tests the full load amps (current) on a three-phase motor (load) it doesn’t show maximum current output from the power plant. An electrical engineer would know this.

Why is it that unloaded stator test don’t confirm a good stator and where did that idea come from? Motorcycle repair shops, manufactures, posts on forms, magazines, or a panel of electrical engineers?

It still hasn't been explained why unloaded tests are bad and how that conclusion came about with sources?

[posplayr]

How are loaded tests going to confirm a good stator? How much current is a stator going to put out under load? Does the manufacture provide that information? If not where does someone get that information?

Wouldn’t a test under load show the current used by the load and not the maximum safe output current of the stator? When someone tests the full load amps (current) on a three-phase motor (load) it doesn’t show maximum current output from the power plant. An electrical engineer would know this.

Why is it that unloaded stator test don’t confirm a good stator and where did that idea come from? Motorcycle repair shops, manufactures, posts on forms, magazines, or a panel of electrical engineers?

It still hasn't been explained why unloaded tests are bad and how that conclusion came about with sources?

Unless you stress the insulation in excess of the operating condition you don't know whether it will break down and is therefore inconclusive. If you measure it and it did break down then that is conclusive. So the question is what does it take to stress the insulation?

Insulation testing was covered in detail in that reference I posted.
Insulation breakdown is a function of many factors but looking at the Megger tests, a high +250V is used to exceed a nominal rating (e.g. 125V). At 5K RPM there is 80 volts leg to leg so that is much better than a ohm meter. The other factor is temperature, where apparently the insulation resistance drops by 1/2 for each increase in 10 degC. These are probably the two most dominant effects other than having the stator be smoked/cooked.

The two tests that you described are probably about as good as you can do as is indicated by your results.( the voltage tests to ground need to be added to the stator pages). The main shortcoming is getting the stator hot, but riding the bike around could do that. These no load tests still don't have any current flowing, which is typically what you would need to get electrical stress, But because the only issue is insulation breakdown when testing the stator alone, the 5K RPM voltage tests will probably capture most all leg to leg and leg to ground faults that the 80V leg to leg voltage can cause to break down.

The dummy load could probably get about 5 amps to flow through each leg without dropping the voltage too much. This would be more thorough if for no other reason to get the stator hotter.The dummy load is pretty easy to configure as the only thing that really matters is the leg to leg voltage is is know. A dummy Y load with 10 ohm resistors

[tkent02]

Kent,
Other than the difficulty of the logistics, the main issue is that you still can not isolate absolutely between a R/R and the stator.

Pop a known good R/R on there, you would know.

[posplayr]

Pop a known good R/R on there, you would know.

yes has been mentioned. Got a good one?

[tkent02]

yes has been mentioned. Got a good one?

A whole bag of them.

[duaneage]

yes has been mentioned. Got a good one?

Yes. Quite a few actually

[Graham]

Unless you stress the insulation in excess of the operating condition you don't know whether it will break down and is therefore inconclusive. If you measure it and it did break down then that is conclusive. So the question is what does it take to stress the insulation?

Insulation testing was covered in detail in that reference I posted.
Insulation breakdown is a function of many factors but looking at the Megger tests, a high +250V is used to exceed a nominal rating (e.g. 125V). At 5K RPM there is 80 volts leg to leg so that is much better than a ohm meter. The other factor is temperature, where apparently the insulation resistance drops by 1/2 for each increase in 10 degC. These are probably the two most dominant effects other than having the stator be smoked/cooked.

The two tests that you described are probably about as good as you can do as is indicated by your results.( the voltage tests to ground need to be added to the stator pages). The main shortcoming is getting the stator hot, but riding the bike around could do that. These no load tests still don't have any current flowing, which is typically what you would need to get electrical stress, But because the only issue is insulation breakdown when testing the stator alone, the 5K RPM voltage tests will probably capture most all leg to leg and leg to ground faults that the 80V leg to leg voltage can cause to break down.

The dummy load could probably get about 5 amps to flow through each leg without dropping the voltage too much. This would be more thorough if for no other reason to get the stator hotter.The dummy load is pretty easy to configure as the only thing that really matters is the leg to leg voltage is is know. A dummy Y load with 10 ohm resistors

If you want to heat the stator to operating temperature then just idle the bike about 25 minutes with a fan blowing on the engine.

Using resistors as a dummy load could pop the resistors or short the stator out. Wouldn't you would need like 400watt resisters at whatever ohms to handle a 5amp load at 80volts. I won’t use a resistor dummy load to test a possible good stator and take a chance of burning it out.

I understood from earlier post a load test was for checking amps (current). And now the load test is for operating temperature and voltage testing.

All a Megger would be good for is checking a ground fault and that would be at very low amps (current). The Megger thing is out of the question anyway because of price alone, Megger $400 vs. stator $100. Motorcycle manufactures do not give the breakdown point for the insulation of stators like the manufactures of industrial motors do, so again the Megger is out.

If a load is really need then just hook it up to a good regulator and turn on all lights, flashers and whatever and test the amps or volts on the stator leads. You still won’t know what the manufacture specs are for this test on a good stator. With out that information the test would be useless.

It seems loaded stator test are bad because of complexity, guessing, theory, test equipment, test procedures and lack of manufacture specifications. How could they be conclusive?

[posplayr]

If you want to heat the stator to operating temperature then just idle the bike about 25 minutes with a fan blowing on the engine.

Using resistors as a dummy load could pop the resistors or short the stator out. Wouldn't you would need like 400watt resisters at whatever ohms to handle a 5amp load at 80volts. I won’t use a resistor dummy load to test a possible good stator and take a chance of burning it out.

I understood from earlier post a load test was for checking amps (current). And now the load test is for operating temperature and voltage testing.

All a Megger would be good for is checking a ground fault and that would be at very low amps (current). The Megger thing is out of the question anyway because of price alone, Megger $400 vs. stator $100. Motorcycle manufactures do not give the breakdown point for the insulation of stators like the manufactures of industrial motors do, so again the Megger is out.

If a load is really need then just hook it up to a good regulator and turn on all lights, flashers and whatever and test the amps or volts on the stator leads. You still won’t know what the manufacture specs are for this test on a good stator. With out that information the test would be useless.

Running for 25 minutes is not really convenient nor good for cams.

The dummy load can be configured to do the same voltage test as open loop, but push current and heat the stator ; the parts should be less than $20 and it is a know configuration not dependent on anything else. Despite your comment; these are simple calculations.

I never suggested anyone use a Megger. If anyone has one they certainly doesn't need me telling them how to use it.

It seems loaded stator test are bad because of complexity, guessing, theory, test equipment, test procedures and lack of manufacture specifications. How could they be conclusive?

Doesn't deserve an answer

[Graham]

Running for 25 minutes is not really convenient nor good for cams.

The dummy load can be configured to do the same voltage test as open loop, but push current and heat the stator ; the parts should be less than $20 and it is a know configuration not dependent on anything else. Despite your comment; these are simple calculations.

I never suggested anyone use a Megger. If anyone has one they certainly doesn't need me telling them how to use it.




Doesn't deserve an answer

Running an engine at idle speed for 25 minutes is like boiling water: easy. The cams will not be hurt because of 25 minutes of idling. Just don’t forget the fan or your engine will overheat. How is this not convenient? Turn the fan on and let it idle as you drink your coffee.

So where are the dummy load numbers?
Resister ohm ____?
Resister wattage ___?
Load current for heating amps___ @ RPM ___?
Voltage under load ___ @ RPM ___?
Time ___ under load to heat stator?
Maximum safe load amps ___?
Benchmark?
If the calculations are so easy then post them. Not just a formula but actual complete calculations with the answers. Like you said simple. How about some old fashion math? Not everyone here has a collage degree so help us dummy loads out.

What do we have if the numbers match or don’t match the calculations?
Confirmed good stator?
Confirmed bad stator?
Unknown stator condition?

I didn’t think you would answer the last question in my last post.
If you don’t wish to answer the questions in this post then don’t.

[posplayr]

Running an engine at idle speed for 25 minutes is like boiling water: easy. The cams will not be hurt because of 25 minutes of idling. Just don’t forget the fan or your engine will overheat. How is this not convenient? Turn the fan on and let it idle as you drink your coffee.

So where are the dummy load numbers?
Resister ohm ____?
Resister wattage ___?
Load current for heating amps___ @ RPM ___?
Voltage under load ___ @ RPM ___?
Time ___ under load to heat stator?
Maximum safe load amps ___?
Benchmark?
If the calculations are so easy then post them. Not just a formula but actual complete calculations with the answers. Like you said simple. How about some old fashion math? Not everyone here has a collage degree so help us dummy loads out.

What do we have if the numbers match or don’t match the calculations?
Confirmed good stator?
Confirmed bad stator?
Unknown stator condition?

I didn’t think you would answer the last question in my last post.
If you don’t wish to answer the questions in this post then don’t.

Your questions are insulting; Is that your intent?

[cowboyup3371]

Pos, I'm not so sure they are insulting especially when I try to follow this and, as I told you in a previous PM, this stuff is above my head. I think this would be a great opportunity to teach a lot of us who may not totally understand things. I can follow math equations if I see them but to try and understand this at a macro level without examples, I'm lost.

[bakalorz]

Running an engine at idle speed for 25 minutes is like boiling water: easy. The cams will not be hurt because of 25 minutes of idling. Just don’t forget the fan or your engine will overheat. How is this not convenient? Turn the fan on and let it idle as you drink your coffee.

So where are the dummy load numbers?
Resister ohm ____?
Resister wattage ___?
Load current for heating amps___ @ RPM ___?
Voltage under load ___ @ RPM ___?
Time ___ under load to heat stator?
Maximum safe load amps ___?
Benchmark?
If the calculations are so easy then post them. Not just a formula but actual complete calculations with the answers. Like you said simple. How about some old fashion math? Not everyone here has a collage degree so help us dummy loads out.

What do we have if the numbers match or don’t match the calculations?
Confirmed good stator?
Confirmed bad stator?
Unknown stator condition?

I didn’t think you would answer the last question in my last post.
If you don’t wish to answer the questions in this post then don’t.

Your questions are insulting; Is that your intent?

Sigh ...

No posplayer, those are not insulting questions, they are not just reasonable questions, the answers to them are required if you ever want to get this entire retarded test of yours off the ground.
What is insulting is insinuating that there is anything wrong with the questions and refusing to provide answers

Earlier salty_monk asked why I called you incompetent. You seem to think that I have a personal dislike for you.
Its not that, but I do have a bad case of SIWOTI syndrome. If I see nonsense posted it bugs me. And its hard to not correct it.

My problem with you is not that you're wrong, but you stubbornly insist you're not, even when you have no justification or argument to support yourself.
Even when multiple people that actually have experience or know what they are talking about tell you you are wrong, you just dig in and bray harder.

I've seen it time after time, in thread after thread. And before you cry about me being rude and calling you names, check this thread to see who was rudest: my first post was not rude; I pulled no punches telling you you were wrong, but there was no namecalling. Your reply was nothing but namecalling.

As far as calling you incompetent, in this thread, aside from the fact that you started the namecalling, you have shown muliple times that you really are not competent to discuss this.
You are way out of your depth here:
You didn't understand why your original test would not work with an OEM R/R ... you didn't (and still don't) understand why a loaded test is no better (and most likely worse) than the AC tests as written ... heck the entire premise of this thread (that unloaded tests are bad) is incorrect ... and your power calculation on a load resistor: not just incompetent and off by a factor of 10, but dangerously so.

THIS ENTIRE THREAD IS A TESTAMENT TO THE FACT THAT YOU DONT KNOW WHAT YOUR TALKING ABOUT.
For some reason you got a bug up your butt that loaded tests are superior to unloaded tests. That statement is SOMETIMES true, but sometimes not. Its context dependent.
You are apparently not competent to judge the context in which it is true, and when its not. This is a case of NOT.

If you disagree, instead of just bleating "unloaded bad, loaded good", provide an actual reason why. In my very first post in this thread I asked you if you actually had some justification for insisting on a loaded test. Because I'm pretty sure you don't. Its just something you came up with, but don't really have any justification for.

Where are the manufacturers loaded tests, where on another forum is there someone else actually advocating something similar, where have you even taken data and proved that your suggested test provides data thats even EQUAL to the unloaded tests (nevermind superior, which is what you claim)

Justify the extravagant claims you are making for loaded tests or just admit that you were wrong.

Until you can prove there is a point to this, as far as I am concerned, all you are doing is causing actual harm ... you are CONFUSING GS troubleshooters with an extraeneous IRRELEVANT test, calling the actual correct useful test "bad" (in the title no less), potentially causing them to waste money on needless tools (current clamps) and test loads (and good luck finding an ADEQUATE dummy load for $20 on ebay), and giving harmful potentially DANGEROUS advice.
... yeah, thats the very definition of competent and helpful ...

For a lot of the simpler issues you can give useful advice. But when you're in over your head you don't know it ... and you are in too deep here. The first rule of holes ... when you're in over your head, stop digging deeper.

If any one actually WANTs to follow the pied piper to stupidville, be my guest; but when he's leading you over the cliff I just might speak out against it. And given his history of stubborn incompetence I won't take any effort to sugar coat it.

SHEESH !