Author Topic: EEVblog #1160 - Weller Responds  (Read 54789 times)

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Offline NANDBlog

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Re: EEVblog #1160 - Weller Responds
« Reply #350 on: December 21, 2018, 08:37:47 pm »
You can blow up stuff with 1W of power with the right conditions.

That would be a feat. Please explain.

Actually, you can choke on your muffin for 0W.

It could be plugged into an IEC plug, so 16A and 240V could go into the box

You have 3800W available in a standard outlet shape? That's a bit worrisome. At least the iron would suffer a quicker, more humane death.

1W setting things on fire.

Yes, I have 3500+W in a standard outlet. Everyone in Europe has. https://en.wikipedia.org/wiki/Schuko
Why would that be worrisome? I also have 50KW electric motor in my car and the wires in the circuit breaker box can deliver 10.000A potentially.

For everyone defending Weller: Why has the more expensive Weller stations a fuse on the primary side if it isn't needed?

Why do more expensive cars have more safety features than cheaper ones?
And all new cars have ABS, ESP, airbag and seatbelt. And if a car doesnt have the advanced features,  they get lower score on Euro NCAP. So there is a third party, who tells them that it is OK, that these features are not mandatory, but your car is 0 star rating. And they publish this data. Just like Dave.
While it might not be mandatory to place a that fuse there, Weller gets 0 stars for this.
 

Offline HKJ

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Re: EEVblog #1160 - Weller Responds
« Reply #351 on: December 21, 2018, 08:46:35 pm »
You are missing a parameter, when the iron in the transformer is saturated the current is not just slightly higher, it is much higher.
I do not have a 120VAC transformer around or I could do a curve of current vs. voltage.
 

Offline floobydust

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Re: EEVblog #1160 - Weller Responds
« Reply #352 on: December 21, 2018, 08:46:50 pm »
Dave's 240VAC blunder is not "normal" operation and merely flushed out the fact that the product is missing a protective element on the primary side.

The (North American) fault condition not covered here is a transformer shorted (or partially) shorted primary or secondary winding. You don't know which two turns in a winding have shorted, it's not always end to end.

You'd have to short the secondary of the 120VAC transformer and see what the primary current rises to, and wait for the house to burn down. This is the danger: no overcurrent protection and a spread of fire under a single fault condition. The secondary winding will heat up. The magnet wire, bobbin, end covers are plastics and will burn. The product enclosure may join in. There may or may not be an arc fault at some point.

This is why a thermal fuse is inside smaller power transformers.
Bigger transformers don't have a thermal fuse because the safety standards require fusing at 167% (some 150%) of rated power.
This overload is enough that they don't get dangerously hot under a fault condition.

Let's go to the casino and bet on the mains breaker tripping, or bet on the product burning up.
 

Online MT

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Re: EEVblog #1160 - Weller Responds
« Reply #353 on: December 21, 2018, 08:50:13 pm »
Soldering iron with augmented reality app??!! Management must be bored ore something"
 

Offline drussell

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Re: EEVblog #1160 - Weller Responds
« Reply #354 on: December 21, 2018, 09:04:31 pm »
You are missing a parameter, when the iron in the transformer is saturated the current is not just slightly higher, it is much higher.

That is a reasonable assumption, however it may or may not be true.  That depends on exactly when that particular transformer design saturates, etc.  Not all transformers will blow up instantly just because you connected them to 50 Hz instead of 60 Hz, or stuck twice the voltage across the primary, although most certainly some will be very unhappy in one or both of those cases.  :)

Quote
I do not have a 120VAC transformer around or I could do a curve of current vs. voltage.

Just taking any ol' transformer and showing a curve doesn't tell us anything about how this one behaves.  I have plenty of transformers around here that are intended to run on 120V but will work fine with a 240V input.  I have plenty more that would definitely go try to go thermonuclear.  :)
 

Offline HKJ

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Re: EEVblog #1160 - Weller Responds
« Reply #355 on: December 21, 2018, 09:30:12 pm »
You are missing a parameter, when the iron in the transformer is saturated the current is not just slightly higher, it is much higher.

That is a reasonable assumption, however it may or may not be true.  That depends on exactly when that particular transformer design saturates, etc.  Not all transformers will blow up instantly just because you connected them to 50 Hz instead of 60 Hz, or stuck twice the voltage across the primary, although most certainly some will be very unhappy in one or both of those cases.  :)

If it not designed to use the transformer iron fully it will, of course, not have serious problems.

Quote
I do
not have a 120VAC transformer around or I could do a curve of current vs. voltage.

Just taking any ol' transformer and showing a curve doesn't tell us anything about how this one behaves.  I have plenty of transformers around here that are intended to run on 120V but will work fine with a 240V input.  I have plenty more that would definitely go try to go thermonuclear.  :)

A Weller 120VAC transformer would be ideal, but any transformer that saturate the iron would give a good idea about what happens.
Anyway I hope somebody with a 120VAC Weller Iron can do a I/V curve for it. I expect it will go nuclear somewhere between 150VAC and 200VAC.
 
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Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #356 on: December 21, 2018, 09:34:45 pm »
the unit draws more than the breaker's rated current fow a while. That means a lot more time overheating, release smoke, and a lot more chances for it to set into fire.

Go ahead and stuff 2000W into a thin copper wire and see how long it lasts.

Which part would set fire? The copper wire or the steel core?
 

Offline Robaroni

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Re: EEVblog #1160 - Weller Responds
« Reply #357 on: December 21, 2018, 09:35:51 pm »
You can blow up stuff with 1W of power with the right conditions.

That would be a feat. Please explain.

Actually, you can choke on your muffin for 0W.


Perfect one liner.
 I'll exit here, it isn't going to get any better. We've beat this topic into complete submission.

Enjoy your Holiday everyone!
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #358 on: December 21, 2018, 09:38:53 pm »
I am just saying, a fuse is much better than an UL melting approved and specified procedure.
I don't know about you, but the lesson I learned here is: Don't plug devices intended for another country into your socket and you will be fine.
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #359 on: December 21, 2018, 09:40:52 pm »
it would still have saved the lab from fire.
What fire?
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #360 on: December 21, 2018, 09:42:37 pm »
For everyone defending Weller: Why has the more expensive Weller stations a fuse on the primary side if it isn't needed?
To save you from a cooked transformer when you make bonehead mistakes, obviously.
 

Offline glarsson

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Re: EEVblog #1160 - Weller Responds
« Reply #361 on: December 21, 2018, 09:42:47 pm »
I have plenty of transformers around here that are intended to run on 120V but will work fine with a 240V input.
Why would Weller, a company saving money by omitting fuses, add extra iron in the transformer? That small transformer probably have just enough iron to survive at 120 volts.
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #362 on: December 21, 2018, 09:44:42 pm »
safety standard that should be deprecated.
Why?
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #363 on: December 21, 2018, 09:46:13 pm »
... and it shows how Weller values its customers.
Maybe Weller think better of you that you won't go sticking thing where you shouldn't. But if you want to avoid embarrassing smoke then it seems like you can buy their higher model.
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #364 on: December 21, 2018, 09:52:52 pm »
You can blow up stuff with 1W of power with the right conditions.
...
1W setting things on fire.

I really hate when I leave my burning laser pointed at sticks of dynamite. That illustrated your point marvelously.  :palm:
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #365 on: December 21, 2018, 09:56:47 pm »
You'd have to short the secondary of the 120VAC transformer and see what the primary current rises to, and wait for the house to burn down.
If I recall, the secondary was fused.


. The magnet wire, bobbin, end covers are plastics and will burn.
Can you substantiate that?
 

Offline glarsson

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Re: EEVblog #1160 - Weller Responds
« Reply #366 on: December 21, 2018, 10:17:39 pm »
For everyone defending Weller: Why has the more expensive Weller stations a fuse on the primary side if it isn't needed?
To save you from a cooked transformer when you make bonehead mistakes, obviously.
What mistake did they who wrote about the incoming 240 volt on their 120 volt service do? You don't have to take your Weller to Australia to make this happen.
 

Offline james_s

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Re: EEVblog #1160 - Weller Responds
« Reply #367 on: December 21, 2018, 10:40:42 pm »
You can blow up stuff with 1W of power with the right conditions.
...
1W setting things on fire.

I really hate when I leave my burning laser pointed at sticks of dynamite. That illustrated your point marvelously.  :palm:

Which point was that?

I accidentally set something on fire with a diode laser years ago. It sounds silly now but at the time a laser capable of starting fires generally meant 3 phase power and water cooling. You wouldn't typically expect something the size of a deck of cards running off some C batteries to do that, but now it's nothing unusual.
 

Offline sibeen

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Re: EEVblog #1160 - Weller Responds
« Reply #368 on: December 21, 2018, 11:53:35 pm »
Since nobody has actually tested anything yet on this particular unit and provided any data, everything thus far is just pure speculation.  :popcorn:

Yes the unit was tested and it was fairly obvious that the current drawn by the transformer exceeded the current carrying capability of the primary winding. This was evident by the amount of smoke released (reported - but by a source some here will trust), and the damage that was viewed after the event. A fuse, sized to protect the primary winding, will have prevented this.

I find it difficult to believe that many here don't get that basic point.
 
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Offline MrMobodies

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Re: EEVblog #1160 - Weller Responds
« Reply #369 on: December 21, 2018, 11:56:22 pm »
There is an saying in England back over 20 - 30 years ago and it was, "Safety doesn't sell". Now they plaster themselves up with safety approvals and certificates and safety words but only up to a compliance on what they can get away with.
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #370 on: December 22, 2018, 01:02:29 am »
For everyone defending Weller: Why has the more expensive Weller stations a fuse on the primary side if it isn't needed?
To save you from a cooked transformer when you make bonehead mistakes, obviously.
What mistake did they who wrote about the incoming 240 volt on their 120 volt service do? You don't have to take your Weller to Australia to make this happen.

So what do you have to do?
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #371 on: December 22, 2018, 01:06:49 am »
You can blow up stuff with 1W of power with the right conditions.
...
1W setting things on fire.

I really hate when I leave my burning laser pointed at sticks of dynamite. That illustrated your point marvelously.  :palm:

Which point was that?

I accidentally set something on fire with a diode laser years ago. It sounds silly now but at the time a laser capable of starting fires generally meant 3 phase power and water cooling. You wouldn't typically expect something the size of a deck of cards running off some C batteries to do that, but now it's nothing unusual.

I think the point was that the small amounts of power can damage stuff. I think that is pretty evident to everybody. I could build a Rube Goldberg to do whatever you like. It doesn't mean that it's realistic.
 

Offline timelessbeing

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Re: EEVblog #1160 - Weller Responds
« Reply #372 on: December 22, 2018, 01:09:38 am »
it was fairly obvious that the current drawn by the transformer exceeded the current carrying capability of the primary winding.

I think it's pretty obvious that the winding WAS carrying the current. Who knows, maybe if you plug it back in , it'll carry it a little longer.

A fuse, sized to protect the primary winding, will have prevented this.

I find it difficult to believe that many here don't get that basic point.
I think you're confused because nobody is denying that point.
 

Online EEVblog

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Re: EEVblog #1160 - Weller Responds
« Reply #373 on: December 22, 2018, 05:26:40 am »
For everyone defending Weller: Why has the more expensive Weller stations a fuse on the primary side if it isn't needed?
Why do more expensive cars have more safety features than cheaper ones?

Except that in this case even the $20 clone cheapies have the fuse. Weller completely fails at competing if nothing else.

The interesting question is why Weller deliberately chose to do this on at least two models.
They have the IEC fuse holder BOM item in other products, so it seems like a no-brainer to re-use it and do the basics of covering your corporate arse.
Saving cost? If that was their goal, why is there no less than three protection devices on the secondary? You could easily get away with one.
 
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Online coppercone2

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Re: EEVblog #1160 - Weller Responds
« Reply #374 on: December 22, 2018, 07:35:34 am »
maybe the fuse is on the edge of the schematic and the cost-cutting team figured out how to hold it just right during the 'glance approval'.\

depends on how their assembly line is setup, potentially it could be manufacturing cost if there is like a work station where one guy does some parts and another guy later does the other parts.

also a chassis mod like a drilling operation is alot of exposure and time (make the guy a marking jig, mark, drill, drill again (enlarge), debur, make sure you did not mess up the chassis, buy a drill for the worker, get the worker keys so he can tighten the fuse holder insert, have him tighten it without scuffing the chassis, insert fuse, tighten, green loctite maybe saves a second). Do their other models have a fuse holder thats externally accessible?

They might be able to ask the manufacturer but it looks to be plastic so you need to do shop work on it.. even so they sometimes don't like to change cad drawings and stuff.

After a line is 'running smooth' for a while I expect they don't like changing anything because its a fine tuned money making machine at that point. They want to remove steps more then anything. In certain setups they want the most zombie like worker possible. And they can pay less because its less skilled then the guy next to him doing two more steps. "we don't need such a high skill level for this job (the other guy that does the higher end station with the drilling step for instance)'. Having two concerent processes of different 'quality' might allow them to make a mask to pay people less.
« Last Edit: December 22, 2018, 07:47:44 am by coppercone2 »
 


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