Stator heat test

Madnorton said:

Suggest you change the rectifier and get a BSM if you are seeing the above. It should be green constantly part from when you put the indicators on. I use RM23, Trispark rectifier and the electric start and the BSM goes green with a minute or so of using the starter.

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That's not the condition
I'm after. BSM is already fitted, that's the colours and voltages
discussed.
I deliberately loaded the alternator heavily then only gave it enough rpm to balance.
That way the regulation is nil for the first test.

"The heat transfer from or to the engine doesn't matter because the effect will be the same for both tests."

That is true but IF the engine is the primary "heat generator" for the stator, then worrying about stator-generated heat is a non issue - it's going to get as hot as its surroundings and different regulators aren't going to change that.

For that matter...is there a large amount of Norton alternator stator meltdowns that is the cause of this concern? Alternators get hot in normal operation; it's what they do!

Obviously, we are talking about heat that is normally generated, by the engine and the stator coils, NOT caused by a malfunction such as improper loading of the electrical system or a misaligned rotor that is grinding against the stator.

Re engine heat etc.

I left out some background information on the assumption that everyone here had that already. That would be the Podtronics testing done by Jeandr.
Have you read that info?
If not I could find it and post the link.
Its possible extra heat due to Podtronics regulation that I'm looking for.
I think if you reread the first post it could clarify things. On the other hand, I might not have explained the test very well. Its a pretty simple test, hopefully it gives us some useful information.


Glen

MexicoMike said:

"The heat transfer from or to the engine doesn't matter because the effect will be the same for both tests."

That is true but IF the engine is the primary "heat generator" for the stator, then worrying about stator-generated heat is a non issue - it's going to get as hot as its surroundings and different regulators aren't going to change that.

For that matter...is there a large amount of Norton alternator stator meltdowns that is the cause of this concern? Alternators get hot in normal operation; it's what they do!

Obviously, we are talking about heat that is normally generated, by the engine and the stator coils, NOT caused by a malfunction such as improper loading of the electrical system or a misaligned rotor that is grinding against the stator.

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The purpose of the test is to actually answer the above with some real life data !

And yes there is quite a list of failed stators, but it’s often difficult to tell cause from effect… did the rub cause the heat? Or did the heat cause the rub? Etc.

The point of Glens test is to provide some clarity. It can’t possibly be a bad thing!

Some of my non-scientific observations.

My stator is attached to the outer primary cover unlike it is on a Commando. I use a TriSpark MOSFET reg/rect. The stator and outer primary cover get friggin hot with the TriSpark reg/rec shunting off energy from a LiFEPO4 battery. It ran cooler with an AGM battery and Podtronics reg/rect, but possible hotter than it would with OEM electronics. I shorted out the Podtronics before I got it to work with the LiFEPO4 battery, so no report on that. 120 watt 2 wire stator. I have no clue about the load, but it is very light, which probably explains why the stator is getting hot with the energy shunted off by the reg/rect with a much stronger battery than a small AGM.

I had the primary off a couple of days ago and the stator still looks good. It did not smell like it was getting cooked. It's still that funky green military color and has not turned black or started to melt. Maybe 1500 miles on the TriSpark and LiFEPO4 battery setup.

The reg/rect does not get hot at all.

Glen,
Off topic:
Weren't you in the process of building a custom 850/920? Did I miss the final chapter?

Well that's done.
The battery was at an all night smorgasbord and just couldn't take anymore. The lights were left off and the vest left at home. So almost the opposite of yesterday's run where the electrical system carried a full load, no v regulation needed.

Today the regulator would have been fully engaged for the entire run, other than a few seconds of idling.


Other than the above, I tried to keep things as close as possible to yesterday's run, same distance, rpm and similar outside air temp, only 1degree f cooler.
The stator temp today with full Podtronics regulation, measured immediately after the run, was 118f. This is virtually the same as with the full load and no regulation.
My conclusion is that whatever the Podtronics does to regulate, it works and it doesn't create any extra heat.
I won't be changing regulators.

Yesterday the Podtronics was cool. I forgot to measure it's temp yesterday, but I did touch it. It was about the same temp as the frame member beside it, maybe 55 f.
Today it felt warm, barely.
The measured temp of the body was 82 f.
I expect that on a long run at high rpm on a hot day with only ignition load it would get quite a bit warmer than this.
On the other hand, I would always run with the lights on so that reduces heat in the regulator.
Either way I'm sure it's up for the job.

Glen

Schwany said:

Glen,
Off topic:
Weren't you in the process of building a custom 850/920? Did I miss the final chapter?

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Yes, I did
get it to the point of riding it around the block, then put it aside to be finished this winter.

Glen

JimNH said:

I don't think there will be much difference. Unlike a car alternator there is no controllable field, just a permanent magnet. Alternator doesn't know if it's dumping current into a vest, headlamp, or heat sink.

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The Podtronics does it a bit differently.
It shorts the output wires of the alternator, not to ground but to each other.
It has been suggested that this is very bad for the stator and would cause a lot of extra heat.
I didn't find that.

Glen

Sounds as if you confirmed that there is no stator issue despite the fears re the "wrong" type of regulator!

Though I didn't personally believe there was an issue - having used a PodT for 8+ years - I commend you for (hopefully) preventing this subject from becoming the electrical teeth-gnashing equivalent of the constant and recurring angst over wet sumping!

Nice job!!!

Well I was in the camp that thought there was a problem, but I’m equally pleased to hear that it seems not to be the case.

If this kind of thing carries on unabated we’ll all have nothing to talk about !!

Which now means the culprit most likely looks to be the Wassell stator, so extra clearance to the rotor is recommended.

Fast Eddie said:

Well I was in the camp that thought there was a problem, but I’m equally pleased to hear that it seems not to be the case.

If this kind of thing carries on unabated we’ll all have nothing to talk about !!

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Well, there is always the "O" word.....

kommando said:

Which now means the culprit most likely looks to be the Wassell stator, so extra clearance to the rotor is recommended.

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Quite possible.

I always ensure a .020” gap / .040” size difference. I’ve had them rub badly before I started doing this.

kommando said:

Which now means the culprit most likely looks to be the Wassell stator, so extra clearance to the rotor is recommended.

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Which version, they have changed again, now brown again not green.

Considering the number of Podtronics sold globally over a good many years, could it realistically be the Podtronic - no. More likely incorrect clearance. Had it been the podtronic the stator failures would be more common, a trend would have been spotted years ago.

Madnorton said:

Which version, they have changed again, now brown again not green.

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The burnt ones I have seen pics of have all been green, but that does not mean the brown are any different if there are not many about. I stick to LAP made ones but very thin on the ground now, TMS were short of them last time I checked but still listed on their website (UK made) .

How was the temp being checked on the stator? Was there a remote wired sensor on the stator or was the primary being taken off to get the reading? If so, there might be enough heat loss/dissipation while dealing with the cover etc that temp readings were dropping down significantly.

This finding sits well with the report I'd read a few years ago, now lost in the many threads on this topic, where someone ran a bench test on the stators while monitoring regulator function (shunting etc) and stator temps. I recall the finding was not much extra heating was found, something like 10 or 20 Cel difference when being shunted. Hardly enough to be excited about.

Stator temp taken thru the primary access hole about 1minute after shut down, both rides.
The test was to look for Delta T with bad old Podtronics doing its worst. The Pod has been called into question for stator damage, especially on bikes fitted with low draw LED lighting
No draw lighting and a fully stuffed battery makes the Pod do its worst.

No Delta T found, so no bad Podtronics.
I'm back to worrying about the head gasket.

Glen

Good info .... I had been fretting that my Podtronics was being overworked after converting to LED lighting. I was considering going to a 3 wire stator and wiring it in with a switch to match the lighting load as was done before zener diodes came along. So now, like Glen, I can worry about something else. Thanks, Glen ...

Slick

Glen - you have a RM23, correct?