Cheap-o regulator rectifier

Given how hard it is to get a regulator rectifier for an old bike (I'm probably going to be waiting 6 more weeks), I thought I'd add a little more to my analysis yesterday (see here) of the failure.

The problem was clearly thermal run-away and (not yet) that of the thermal paste (which isn't used anything like properly). So lets start with what the regulator rectifier looked like on extraction from the bike.

The bulge and the spatters of metal (yes, metal) indicate high temperatures (to melt the metal).

So I cut the arse of it off and chiselled it out.

Which shows that there was still some thermal paste, but also that there was not a good physical connection to the metal of the heat sink (because its quite rough looking, ideally it should be polished smooth. So that's manufacturing failure #1

Next we flip that black box over and see that its easy to split (its already fractured)

and we can see the guts ... of course the board is burned down to glass fibers in places. Not only is the heat escape pathway interesting, but what the fcuk are these little chunks of white rock doing in here?

you can see that the not only are the components toast, but we can see the legs of the coponents are totally gone too

This would explain the tiny spatters of molten metal above.

Lastly the thing stinks, probably due to the boiling of the organic solvents used in the (copiously applied) thermal paste.

On this point I'm going to say that cheap thermal paste that uses organic solvents, when applied like a kids use of toothpaste is a recipe for disaster longer term. This is because any significant heat (say, over 50C) is likely to see the loss of this material over time; weakening the effectiveness of the transfer of heat from components to outer case.

So if I was you, as well as making sure it stays cooler (as I examined in the previous post)  I'd be replacing these things pre-preemptively after every few tens of thousand hours (roughly equal to kilometers) or per few years on bikes that don't get used much. Especially if you use your bike on hot days (like Australia, California or other hot dry places).

HTH

T-Max cheapo regulator rectifier

So, it happened again...

My nose identified the smell of burning insulation and electrolyte, and I noted some smoke emerging from "down there".

I quickly pulled off the road (smoke being spread by the fan) shut off the ignition, pulled the tool kit and disconnected the battery.

This left me on the side of the road, so I pushed it down a lane a little ways (to keep it from attracting the wrong kind of attention), hitch hiked home (I was on the way home), got my truck and came back with a new part and tools.

It requires a bit of jiggery to organise me getting back both vehicles.

Readers of my blog will know of my previous issue (documented here) and my conjecture of would it survive the hottest days ... I'm pretty sure I know the answer now ;-)

As I wrote back then when I fitted the fan unit:

I was riding around and thinking about how close that graph got to 50C and thought that since the air temperature right now is like 20C (middle of the day) and that in summer its going to be nearly 50C (coming directly off the road) that will drive that temperature up closer to limits again. So I decided to look for power and attach a small case fan to assist cooling.

So as I suspected on at +34C day it didn't get sufficient cooling.

I decided that I needed to do new testing (because it was still bloody hot) and so I thought test it with

• cover on (fan cooled only)
• cover off (fan still there)

To test I embedded a sensor between fins to avoid air cooling of the sensor (and get the temperature of the heatsink) like this:

*(Note: the new cheapo part is no longer black, which is stupid)

The "cover off  ride looks like this

with good exposure to air for the cooling. The temperature plot (which included a length of highway at 100km/h)

which is quite reasonable. You'll note that temperature rose as soon as I returned into 60km/h town region and stopped recording when I pulled into my yard.

I then slipped the cover on 

note the breather which is a vent (see the earlier post) that leads to the center of the fan (and hopefully blows fresh road air in).

and went back out, getting this reading

you'll note that it got to 60 pretty soon and flattened (I was keeping an eye on the meter readout) and rose briefly when I was back in town (presumably due to lower air flows.

This temperature is very close to thermal runaway temperatures and IMO far too warm for a cheap piece of shit like this. This site on that subject makes that clear.

Semiconductor parts are most often specified for use in the “commercial” 0 to 70°C and, to a lesser extent, in the “industrial” -40 to 85°C operating temperature range. These operating temperature ratings generally satisfy the demands of the dominant semiconductor customers in the computer, telecommunications, and consumer electronic industries.

So I've ordered a Yamaha part to test. I want to know if the part that costs $300 is worth its money. Perhaps it may run cooler?

I'll post more when it comes to hand. For now its not being ridden.

Addendum

So, as promised, I took the T-Max into Warwick (37km) on a warm (but not scorching) 29 ~ 30C day (just a few days after this was first written). The results were very interesting. First the full trip

We start off with the surface of the heatsink being 25C, and I let it sit for a little while before starting off. I did the same when I got back. I rode into town, parked at a hardware shop at about 9:40. The temperature of the heat sink started to rise after the air flow stopped (I presume as the hotter parts inside the unit transferred their heat out and it was radiated away).

I then rode to another shop (quite close) which resulted in a quick air cooling and then a smaller rise. I was there until about 10:15, where I started up and rode home.

Lastly, after getting home I let it sit for a bit before shutting off the data recorder.

The trip in. Please note that in this graph I removed temperatures below 20 which does tend to change the actual scale of the graph, it also makes it a bit easier to see. I topped it out at 60C because I feel that's the danger zone.

The trip home.

Again we see that as soon as it is generating heat (by rectifying the AC from the alternator into DC and regulating that and dumping what the battery doesn't require as heat) its also moving, and when its moving slower things heat up faster. You can see when I come into town, slowing down and getting less air cooling.

So next I'd need to test this in traffic ...

I'll keep you posted

Heart Valve Choices - an update of related information

Some years back (ten years back) I wrote this blog post on heart valve choices in the hope of adding a small voice into a large and noisy discussion room.

In that post I mention a video presentation by Dr Schaff of the Mayo, which for various reasons I believe fell off the Mayo Website for no reason other than administrative.

I recently found this updated presentation of his on YouTube and see that his views have remained the same (facts often don't change) and his inclusion of TAVI is a welcome addition.

 So here is his presentation:

It doesn't surprise me that the Mayo is using the YouTube platform, because administratively it is far easier to off load storage and server loads onto YouTube than bear it yourself. Many Universities are also doing the same thing.

I strongly recommend that if you're in the market for a valve and under 70 years of age you watch that and think carefully not only about what he says, but how many surgeons at his conference who are unaware of the actual data. For example stroke risks:

Worth noting the graphical presentation "steps" suggests that less data exists for Bioprosthetic when you look at the last "step". I would submit that this is likely due to bioprosthesis being on average removed by that duration of time.

All too often I hear "surgeons know better" ... the reality is "maybe they do" combined with "it depends on the specific question".

Anyway, with any discussion of mechanical valves we must understand the other issues that come with that (and will as you'll see in the presentation may well come with bioprosthesis anyway)

One of the topics introduced there is Anti-Coagulation Therapy (AKA Blood Thinners) and the misconceptions of patients about this. I've written blog posts about that for example here, as well as an entire series on INR related issues, which of course includes that post.

As well as deciding about the valve we need to decide about what we think we will want for ourselves in 10 or 15 years time ... do you just want to be still managing a medication (you'll have more of them by then anyway) or staring down your next surgery?

Lastly (and not unimportantly) I recommend this discussion too:

https://www.medscape.com/viewarticle/838221

It covers some interesting topics. You may have trouble with that page (depending) because the audio is not rendering properly on Chrome on Windows (but is ok on Linux and Android phone). You should see a media player like this:

or perhaps a link advising you to update your Flash plugins (omg). If it doesn't work then you may be able to download the MP3 file directly using this link https://bi.medscape.com/pi/editorial/studio/audio/2015/core/838221.mp3 (which I took from the HTML I got).

I hope you find this helpful in your analysis of what's best for you in the long term.

Happy New Year

Well its just into the New Year and I'm reflecting on a busy year gone, not sure what the new year will bring, but today I went out for a nice afternoon ride (late to avoid the heat) on the SR

Aside from some watch wanking, I've managed to complete or tidy up a few projects, not least of which was finally finishing off the rebuild of the front end on the T-Max

which included:

• wheel bearings
• full brake caliper rebuild
• fork rebuild
• steering head bearings
• new tyres

Basically I already know how much of a PITA it is to do the steering head bearing (not least because of all the tupperware that needs to come off) but because of the length of the steering head tube. I've more or less perfected this now, as I've done it once before on my last T-Max

Have also bought two other motorbikes and sold one of them (so leaving me with the T-Max and the SR500). I'm probably going to be doing some work to the SR500 soon, so now that the T-Max is back together (and riding very nicely) I can perhaps swap which bike is in the spot.

Solar floor heating system is now looking more modular and we'll see how well it "goes back together" come May.

I consistently enjoy having my workshop and all the experimental learning that making it has brought.

The INR management book was written but I've not published it formally yet due to concerns about possible liability (and a lack of liability insurance), but I'm hoping to get something happening this year with maybe some clinical trial.

I sent this "cover idea" to a friend who's returned a cover based on this which I like more. But I also like this title.

Still, I'm told it sounds too geeky to sell well, and ... well I don't want it to sell to people who aren't just that bit geeky anyway. It is by nature "not for fools or idiots".

At the very least I feel I've learned a quite few things this year, improved my skills in some areas, and perhaps most importantly found myself more adjusted to my "new life" without my wife. So, what's that, over 11 years, under 12.

Looking forward to what will happen in the year before me, well I just don't know. I don't actually have any plans.

Lets see what happens.

I hope you have a healthy, happy and enriching New Year