EEVblog #1160 - Weller Responds

[floobydust]

From old WTCPT manual for the iron that burnt down, no primary fuse

I have this schematic for WTCPT Rev. 8/2002 that matches the station I have and the pics, I got it around 1998.
Note the primary fuse was added and secondary only fuse was deleted- over 20 years ago. Weller has already gone back to the future 

[Muttley Snickers]

My old Weller-Ungar 921-ZX has a fuse on the primary side, in fact they put the holder for it on the front of the unit so it's easily accessible, and no IEC socket either so you can't stuff it up. This station would probably go for another two decades except for the minor issue of Weller no longer providing replacement tips for it and I'm on my last one.     

[IanB]

I don't know if this has been asked before because there are too many pages of this thread to read through. BUT:

Could someone do an actual experiment to test the assumption that a fuse would help? Wire a suitably rated fuse into the mains cord of a 120 V Weller iron and demonstrate that the fuse does not blow under normal use at 120 V with any load on the iron, but that the same fuse blows quickly if the iron is plugged into 240 V?

Will a normal over current fuse behave this way, or would it require a thermal fuse built into the transformer?

[Electro Detective]

Logic, common sense and sound business practice to score repeat and loyal customers would fit both to cover all bases 

or hang all that, fit both just so the CEO and staff at Weller can sleep better   

------------------

FWIW I don't agree DJ should cop the rap of 'user error' on a unit made by a company that flogs it's wares to a 120 volt @ 60 hz nation that also has a 240 volt supply.


DJ plugged it in and the unit smoked because the manufacturer FAILED to deploy a cheap fusing device to prevent an input voltage mishap,
and no real obvious appropriate caution labeling   

Had DJ tried to run the unit from a 120 volt ugly square wave inverter, some aviation 400hz thingie or a dimmer buzz adapter to control the temperature, and the unit smoked or popped a lamination after a time,
well, that's definitely a strong case for 'user error'

[Mr. Scram]

Because people keep asking over and over again why people are making a big deal over this. And they keep coming back with the argument that it's 240V into a 120V tranny so it deserved to fail etc.

I don't know if this has been asked before because there are too many pages of this thread to read through. BUT:

Could someone do an actual experiment to test the assumption that a fuse would help? Wire a suitably rated fuse into the mains cord of a 120 V Weller iron and demonstrate that the fuse does not blow under normal use at 120 V with any load on the iron, but that the same fuse blows quickly if the iron is plugged into 240 V?

Will a normal over current fuse behave this way, or would it require a thermal fuse built into the transformer?

That has indeed been discussed before and would be an interesting experiment. However, it seems the discussion has moved beyond that and now mainly is about whether the fuse it absolutely required when only using the appropriate voltages and whether other things may be in play which mitigate the obvious fuse equals bad.

[Mr. Scram]

Wow, that is pretty ironic!
We have also read your opinions multiple times, but many of us clearly don't agree with it - just as you don't agree with ours.

Weller have yet to provide a decent response.  Hopefully after the holidays they will - else they will likely see a measurable hit on sales targets.

It doesn't seem it's about seeing an opinion more than once, it's about seeing the same argument used more than once while the reply to it hasn't been countered or addressed.

However, Weller seeing "a measurable impact on sales targets" would be an example of the sometimes overly dramatic statements being made here. If you eliminate the outrage, there's actually not that much quantified or to go on. It seems doubtful that will have a huge impact or even any impact at all.

[SeanB]

I don't know if this has been asked before because there are too many pages of this thread to read through. BUT:

Could someone do an actual experiment to test the assumption that a fuse would help? Wire a suitably rated fuse into the mains cord of a 120 V Weller iron and demonstrate that the fuse does not blow under normal use at 120 V with any load on the iron, but that the same fuse blows quickly if the iron is plugged into 240 V?

Will a normal over current fuse behave this way, or would it require a thermal fuse built into the transformer?

Was looking in the garage and found an old 220/120 autotransformer, 200VA or so, and the lovely type with deathdaptor input, so it can be used either way.
Wonder if I should dig up a US style 2 pin plug and connect that, along with a 1A circuit breaker ( those are special order from Hymag, they normally only go down to 5A as standard) that is rated to 3ka  as per IEC 947-2, and see if the breaker will trip before the transformer goes bang, and then test to see, using a 20A breaker, if that will trip before the smoke comes out.

[TheDane]

Logic, common sense and sound business practice to score repeat and loyal customers would fit both to cover all bases 

or hang all that, fit both just so the CEO and staff at Weller can sleep better   

------------------

FWIW I don't agree DJ should cop the rap of 'user error' on a unit made by a company that flogs it's wares to a 120 volt @ 60 hz nation that also has a 240 volt supply.


DJ plugged it in and the unit smoked because the manufacturer FAILED to deploy a cheap fusing device to prevent an input voltage mishap,
and no real obvious appropriate caution labeling   

Had DJ tried to run the unit from a 120 volt ugly square wave inverter, some aviation 400hz thingie or a dimmer buzz adapter to control the temperature, and the unit smoked or popped a lamination after a time,
well, that's definitely a strong case for 'user error'

Who says it always is due to 'user error' ??

A fault with the power delivery system, say a missing neutral or insufficent grounding, and your mains 120V system could face 240V across L-N.
I have personally seen an extremly expensive projecter burn and die due to a such an error. The neutral connection at the convention center was not tightened well enough, eventually causing a thermal runaway situation before it disconnected/opened. Result: 240V mains was suddenly 380V, as this was the only phase-neutral drawing large amounts of power at the time. Fortunately a replacement could be fetched in time, though it was not nearly as good.

Some people hope/wish for the best, and if they are assured nothing will happen - nothing should, right?
Famous last words, I thought ... (and <gulp> I was wrong)

Difference in culture and opinion, what is common sence and so on. I totally understand why some people are so paranoid, it's usually those who has already been burned in the past :-)

[Kleinstein]

I don't know if this has been asked before because there are too many pages of this thread to read through. BUT:

Could someone do an actual experiment to test the assumption that a fuse would help? Wire a suitably rated fuse into the mains cord of a 120 V Weller iron and demonstrate that the fuse does not blow under normal use at 120 V with any load on the iron, but that the same fuse blows quickly if the iron is plugged into 240 V?

Will a normal over current fuse behave this way, or would it require a thermal fuse built into the transformer?

I would expect a correctly chose fuse to blow faster than the transformer. At 230 V instead of 240 V the transformer would go into saturation and thus should have quite massive current peaks. Chances are good the fuse would even protect the transformer from damage.

However the case of using the 120 V version on 240 V (e.g. in Australia or with failing neutral in a split phase installation, accidentally getting 208 V) is not that main reason for having a fuse.  The main reason would be the possibility of transformer faults that can cause the transformer to run too hot. Here just a primary fuse may not blow very fast, maybe only after the damage to the transformer gets larger due to overheating. So the safer way would be a thermal fuse.

It's just that Weller should have spend some 50 cents extra on a transformer with thermal fuse inside. A primary fuse may than be optional.

[fsr]

AFAICT many concerned posts here are not solely or remotely based on "conjecture and perception" but on equipment safety and reliabilty/longevity in the event of a fault, be it an internal or external cause

i.e. the fuse blows, immediate danger averted, there is no assumption required that Weller 'may' or may not actually performed actual proper engineering,
nor why they really cheaped out on 120 volt customers, with apologist PR quickie BS identifying their units as low hazard risks.

A cheap properly rated fuse arrangement is an easy upgrade to very low hazard to no hazard status,
and helps the manufacturer keep a low hazard distance from courtrooms 

----------------------------

FWIW to GFCI and RCD "faithers",
if the unfused soldering station is smouldering away nicely, chances are excellent the GFCI, RCD, MCB, RCBO will not trip 

Completely agree.
The discussion about the GFCIs was about the claim that "110v won't kill". Well, they will, at least under certain circumstances, or there would be no GFCIs installed at all.
I readed that the voltage legally considered safe to "touch" is between 40 and 50v in most places.

[Mr. Scram]

Completely agree.
The discussion about the GFCIs was about the claim that "110v won't kill". Well, they will, at least under certain circumstances, or there would be no GFCIs installed at all.
I readed that the voltage legally considered safe to "touch" is between 40 and 50v in most places.

I would really help if the actual arguments aren't misinterpreted or misrepresented. As far as I'm aware nobody here claimed 110V can't kill. It is however much less likely to kill than 240V. The GFCI not being a black and white thing is illustrated by them not being used or required in all places with well developed safety regimes. It that regard it's a lot like the discussion here, which isn't as black and white as some people would make it seem in their enthusiasm to pile on. Kleinstein's remark on how a thermal fuse may be more appropriate than a primary fuse is a good example of how things are probably a bit more nuanced than "no primary fuse = bad".

[Wolfgang]

The discussion here is running along the "are safety belts really neccessary ?" lines. Fuses prevent major damages even if such events are (hopefully, I dont know where else Weller has cut corners) rare. Not everything that is (barely) legel and increases profit (by a ridiculous amount) is smart in the end.

It really isn't. I don't think people here will make the mistake thinking that slapping on a safety device will automatically make things safer. Note that I'm not defending Weller not using a fuse. I'm simply trying to view the matter from different sides, looking at the actual facts we have. Dave wasn't afraid to admit the problem in the video was user error. That leaves the question how much of a problem not having a fuse really is if you don't grossly overload the device. A decision I don't understand could very well be an opportunity to learn about something I hadn't considered before, but someone else did figure out. I've seen more than one teardown which shows something which seems a terrible idea, but actually turns out to work remarkably well. Are there reasons this design may be reasonable, like transformers inherently limiting the current or different transformer designs being used between the US and EU model? Are there other things we may be overlooking? If there's a negative impact, can we quantify it? Or is this really penny pinching of the kind we all hate? Some people seem really keen on getting out the pitchforks and don't seem to mind fabricating provocative stories to justify their outrage and that's what I object to. I don't feel the fundamentalist approach and piling on is very appealing, and alternatively hope to tap into the considerable knowledge of the population here to maybe learn a thing or two.

... in other words, you try to practice tolerance and understanding for the unworthy. I do not see *one* honest reason (greed excluded) for not using a primary side protection device like a fuse or a thermofuse. Its so simple - even if failures and injuries are rare, you still have a good point eliminating them. If profit comes first - bad choice, especially for a "premium" product. All the desparate reasearch for a good reason why Weller (they are still working on their response ...) did this is academic and a bit futile, no ? 

Discussion about safety belts have subsided after a few years, IIRC. Common sense will prevail in the end (I am an optimist) 

[timelessbeing]

Dave, this is the third time you've repeated yourself. I've attempted to answer you twice already, so I'll let you scroll back. But really, the only ones who can answer that are Weller.

Because people keep asking over and over again why people are making a big deal over this. And they keep coming back with the argument that it's 240V into a 120V tranny so it deserved to fail etc.

Right, so you post without reading. The fuse justification you keep repeating is that Weller puts them in their higher end stations. Explain.

A Cadillac comes with lane keep cameras. A Chevy Spark does not.

[Mr. Scram]

... in other words, you try to practice tolerance and understanding for the unworthy. I do not see *one* honest reason (greed excluded) for a primary side protection device like a fuse or a thermofuse. Its so simple - even if failures and injuries are rare, you still have a good point eliminating them. If profit comes first - bad choice, especially for a "premium" product. All the desparate reasearch for a good reason why Weller (they are still working on their response ...) did this is academic and a bit futile, no ? 

Discussion about safety belts have subsided after a few years, IIRC. Common sense will prevail in the end (I am an optimist) 

I'm merely willing to accept that I may not have the full picture, and won't join a witch hunt as a consequence. Again, I've seen too many solutions which seem terrible at first glance, but which turn out to be fine. A recent example would be the plastic car ramps discussed in the TEA thread. Both my gut and experience tell me that's a terrible idea, yet the company has sold them for two decades or more. That must mean they're fine, even though I would have agreed with anyone crucifying the manufacturer if they were first introduced today.

[timelessbeing]

Had DJ tried to run the unit from a 120 volt ugly square wave inverter, some aviation 400hz thingie or a dimmer buzz adapter to control the temperature

  Oh yah , I hate it when I can't use my iron on a long haul flight. A dimmer buzz adapter??

Why does everyone try to keep coming up with the most obscure use cases? Most people plug their iron in at their bench and there it lives. End of story.

I have exactly two 240V outlets in my house. One for the stove, and one for the dryer, and they're pretty difficult to mix up.

[timelessbeing]

Dave, this is the third time you've repeated yourself.

Wow, that is pretty ironic!
We have also read your opinions multiple times, but many of us clearly don't agree with it - just as you don't agree with ours.

There was no back and forth discussion. I'm talking about just spewing an opinion over and over without explaining it, or listening to/addressing the responses.

they will likely see a measurable hit on sales targets.

wishful thinking

[timelessbeing]

even if failures and injuries are rare, you still have a good point eliminating them.

So we should protect against each kind of failure, no matter how rare, even 1/1,000,000? That would be quite a task.
Please do some reading about cost-benefit analysis.

[timelessbeing]

the discussion here, which isn't as black and white as some people would make it seem in their enthusiasm to pile on. Kleinstein's remark on how a thermal fuse may be more appropriate than a primary fuse is a good example of how things are probably a bit more nuanced than "no primary fuse = bad".

  No no no. This is the internet. We exploit irrational fears to set up an extreme knee-jerk reaction, draw lines, set up a scapegoat to crucify, and we all jump on the tribe bandwagon. We paint mushy dissenters as the enemy and burn them, thus reinforcing our previously held beliefs. No prisoners. No compromise!  That's how progress works

[Wolfgang]

Thanks for the tip, but I was working for years in the insurance industry. Cost/benefit/probability considerations were daily business.
The failure rate of electrical equipment has been improved *despite* the fact that the chance of suffering an electrical accident was quite low in the last years (before Chinese crap took over). Still, the laws and regulations have been strengthened a lot, and for a good cause. The *cost* of a failure can easily exceed millions (fire, causalties, injuries, ...) while the cost to prevent something like that can be really small (Weller case). So, as you write, a 1:1 Million chance can be a good reason to act. I am quite sure that the chance of a Weller blowing up is one or two orders of magnitude higher than 1:1E6.

[cdev]

The problem with cost-benefit analyses is that they tend to underestimate the very real costs of non-safety and overestimate the benefits of cutting corners, for various reasons which would only make us angry.

As a recent poll showed that Weller is the most commonly used brand here in this forum, maybe they'll change their minds.

even if failures and injuries are rare, you still have a good point eliminating them.

So we should protect against each kind of failure, no matter how rare, even 1/1,000,000? That would be quite a task.
Please do some reading about cost-benefit analysis.

[Wolfgang]

the discussion here, which isn't as black and white as some people would make it seem in their enthusiasm to pile on. Kleinstein's remark on how a thermal fuse may be more appropriate than a primary fuse is a good example of how things are probably a bit more nuanced than "no primary fuse = bad".

  No no no. This is the internet. We exploit irrational fears to set up an extreme knee-jerk reaction, draw lines, set up a scapegoat to crucify, and we all jump on the tribe bandwagon. We paint mushy dissenters as the enemy and burn them, thus reinforcing our previously held beliefs. No prisoners. No compromise!  That's how progress works

YES !!! All people that cut corners on safety that cost just a penny should rot in *HELL*. 

[timelessbeing]

I totally understand why some people are so paranoid, it's usually those who has already been burned in the past :-)

I think think different people handle trauma in different ways. Most people employ "flight" and do everything they can to avoid future confrontations, and possibly blame others for their misfortune.

Others try to learn what happened and why, analyze it rationally, and then try to change their approach. It's like learning to swim.

I've gotten the 120V handshake several times, and I have a better understanding of it as a result. I don't cower from outlets or go install GFCIs on everything.

[Wolfgang]

I totally understand why some people are so paranoid, it's usually those who has already been burned in the past :-)

I think think different people handle trauma in different ways. Most people employ "flight" and do everything they can to avoid future confrontations, and possibly blame others for their misfortune.

Others try to learn what happened and why, analyze it rationally, and then try to change their approach. It's like learning to swim.

I've gotten the 120V handshake several times, and I have a better understanding of it as a result. I don't cower from outlets or go install GFCIs on everything.

One of this forums members got the slogan "Safety measures hinder evolution". Come on, just be a part of it !

[timelessbeing]

The *cost* of a failure can easily exceed millions (fire, causalties, injuries, ...) ... the chance of a Weller blowing up is one or two orders of magnitude higher than 1:1E6.... people that cut corners on safety

Pure conjecture.

[EEVblog]

FWIW I don't agree DJ should cop the rap of 'user error' on a unit made by a company that flogs it's wares to a 120 volt @ 60 hz nation that also has a 240 volt supply.

DJ plugged it in and the unit smoked because the manufacturer FAILED to deploy a cheap fusing device to prevent an input voltage mishap,
and no real obvious appropriate caution labeling   

I'll still happily cop the user error tag.
But I do think that the use of a universal IEC socket without a mains fuse is begging for trouble in today's global economy. And the voltage label is on the bottom, not the back where the plug is.
If it had a fixed mains cable and 120V plug (like Hakko do) then they could get away with it. But even in this case, Hakko have a fuse.