Author Topic: EEVblog #1160 - Weller Responds  (Read 55810 times)

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Online Fungus

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Re: EEVblog #1160 - Weller Responds
« Reply #175 on: December 19, 2018, 01:31:18 pm »
I have opened a lot of wall warts and small electronics (clock radio, etc) and very few have a fuse, it is not a requirement.

a) Most (all?) wall warts use switch mode supplies and will accept a wide range of input voltages, even DC.

(do you own wall warts with huge iron transformers in them?)


b) The "requirement" will be that that devices fail safely, not that they must have fuses.

The reason fuses are being discussed here is that a fuse would be a cheap way to make Weller soldering stations fail safely. No other reason.
 
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Offline eugenenine

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Re: EEVblog #1160 - Weller Responds
« Reply #176 on: December 19, 2018, 02:15:38 pm »
I have opened a lot of wall warts and small electronics (clock radio, etc) and very few have a fuse, it is not a requirement.

a) Most (all?) wall warts use switch mode supplies and will accept a wide range of input voltages, even DC.

(do you own wall warts with huge iron transformers in them?)


b) The "requirement" will be that that devices fail safely, not that they must have fuses.

The reason fuses are being discussed here is that a fuse would be a cheap way to make Weller soldering stations fail safely. No other reason.

a) Lots of non high current phone chargers are transformers.  The 200mA to charge a cordless screwdriver, the charger for the FRS radios you can but anywhere, chargers for cheap razor/trimmers, cordless phones, etc.  I've torn apart some simple radios, with and without clocks that had a simple transformer wired direct to the cord with no primary fuse.

even simple heating appliances like a toaster typically don't have a fuse in the main cord.

Yes, cell phones are switching but most other wall warts are not.

b) I was disputing someone saying fuses are a requirement, I haven't see anything that states fuses are a requirement and have seen plenty of evidence to show that fuses are not a requirement.
 

Offline capt bullshot

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Re: EEVblog #1160 - Weller Responds
« Reply #177 on: December 19, 2018, 02:16:10 pm »


SCNR  ;)
Safety devices hinder evolution
 

Offline EEVblog

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Re: EEVblog #1160 - Weller Responds
« Reply #178 on: December 19, 2018, 02:26:34 pm »
Your home stereo, wall warts, clock radio etc. consumer electronics all require a primary fuse of some sort in the power transformer.

Not according to a direct quote from a product engineer at Weller, see my previous post for this.
 

Offline Ice-Tea

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Re: EEVblog #1160 - Weller Responds
« Reply #179 on: December 19, 2018, 02:27:56 pm »
your  not supposed to blow breakers. your not supposed to shut down an entire work bench and possibly room lights and smoke the joint up because of a 50 cent part. whoever designed this standard is a fucking moron

They were drafting an electrical safety standard. Not a convenience standard.

tripping a breaker is a safety issue.


Is it? I think you are still confusing "safety" with "convenience".

Quote
so is toxic smoke.

- What is your proof that the smoke is toxic?
- Even if it is, that's well beyond the scope of an electrical safety standard.


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Offline EEVblog

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Re: EEVblog #1160 - Weller Responds
« Reply #180 on: December 19, 2018, 02:28:31 pm »
Louis Rossmann joined in the rant... check his YT channel.  :box:

Haven't watched it, but I'm sure it's good  ;D

 

Offline 2N3055

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Re: EEVblog #1160 - Weller Responds
« Reply #181 on: December 19, 2018, 02:30:10 pm »
I have Weller WD1.
It has primary fuse and thermal fuse in transformer.
Problem is that 110V version specifies fuse of 1 A. 1A fuse will not blow if you connect 110V station into 240V in a time to save transformer.

Transformer might or might not overheat into short circuit. Some of them will just keep on smoldering. If primary wire is thin enough, it might even fail open.
Transformer wire coating is temperature resistant and flame retardant. If you heat it enough, it might char and become conductive, but not short, not immediately...
Current will rise slowly, until it finally either shorts, or breaks open.
If device catches fire it is usually case or something else made of non fire retardant plastic.
If exists thermal fuse will trip and kill off transformer. Thermal fuse is permanent disable, because if it trips, it is considered that temperature was so high that insulation of transformer was compromised, and should not be used anymore even if it seems to work.
Transformer can be designed to fail open.

Primary fuse is there mainly if short circuit does happen, and serves only to avoid your external fuse trip on a power distribution, so it doesn't shut off other devices.
 

Offline Richard Crowley

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Re: EEVblog #1160 - Weller Responds
« Reply #182 on: December 19, 2018, 02:32:59 pm »
b) I was disputing someone saying fuses are a requirement, I haven't see anything that states fuses are a requirement and have seen plenty of evidence to show that fuses are not a requirement.
The issue here (as I see it) is not "requirement" as much as "SAFETY" and perhaps "common sense".
Small wall-wart power supplies are by definition low-current, low-power devices. The "old-school" variety that use iron-core, mains-frequency 120V transformers will likely fail quickly when connected to 220V because the primary wire gauge is so small, approaching the wire gauge in a fuse.

Of course, the "old-school" iron-core, mains-frequency transformers are becoming rare as it is cheaper here in the 21st century to use switch-mode power supplies (SMPS). And many (most?) of those SMPS are "universal" to handle anything from 100V (Japan) to 240V (UK) mains voltages.

OTOH it is probably silly to expect common sense here in the 21st century.

Producing a high-power device that is hard-wired for 120V and has a "universal" power inlet connector and NO FUSE is just asking for trouble.  It is trivial to grab a handy power cord and just quickly plug it in. But if you are in a 220-240 part of the world, it results in this kind of nasty failure and potential disaster. 

As a user of Weller soldering gear for over 50 years, I find this kind of short-sightedness to be quite disappointing.  And the typical legal CYA response to be reprehensible and remarkably condescending and contemptuous.
 

Offline Ice-Tea

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Re: EEVblog #1160 - Weller Responds
« Reply #183 on: December 19, 2018, 02:38:32 pm »
Quote
They were drafting an electrical safety standard. Not a convenience standard.

This thread has nothing to do with "standards",

It doesn't? Weller claims it's a certified product and complies to applicable standards. So the that begs the question if that's correct or not.

Quote
it's here because:

a) Weller should know better than to sell an unfused device that could easily end up in a different country in 2018 (eg. ebay has been around for over 20 years).

Doesn't even have anything to do with 110/230V IMO. Stuff breaks, even when used on the correct voltage.

Quote
Anybody quoting standards at each other has clearly missed the main point.

Or, you know, people that are considering/quoting standards take it as a given that Weller did a dumbass thing, should burn on the cross for that but are still intellectually triggered by the underlying standards and reasoning...
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Online Fungus

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Re: EEVblog #1160 - Weller Responds
« Reply #184 on: December 19, 2018, 02:40:45 pm »
Louis Rossmann joined in the rant... check his YT channel.  :box:

Haven't watched it, but I'm sure it's good  ;D

Weller should be going into damage control soon.


I hadn't thought too much about that phrase in the Weller brochure. Let me reproduce it here for posterity.


I'm sure no comments are needed, it speaks for itself.
 

Offline Mr. Scram

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Re: EEVblog #1160 - Weller Responds
« Reply #185 on: December 19, 2018, 02:41:42 pm »
I have Weller WD1.
It has primary fuse and thermal fuse in transformer.
Problem is that 110V version specifies fuse of 1 A. 1A fuse will not blow if you connect 110V station into 240V in a time to save transformer.

Transformer might or might not overheat into short circuit. Some of them will just keep on smoldering. If primary wire is thin enough, it might even fail open.
Transformer wire coating is temperature resistant and flame retardant. If you heat it enough, it might char and become conductive, but not short, not immediately...
Current will rise slowly, until it finally either shorts, or breaks open.
If device catches fire it is usually case or something else made of non fire retardant plastic.
If exists thermal fuse will trip and kill off transformer. Thermal fuse is permanent disable, because if it trips, it is considered that temperature was so high that insulation of transformer was compromised, and should not be used anymore even if it seems to work.
Transformer can be designed to fail open.

Primary fuse is there mainly if short circuit does happen, and serves only to avoid your external fuse trip on a power distribution, so it doesn't shut off other devices.
Good point. The specified fuses on dual voltage devices tend to be different, so if people simply plug in the device into the wrong mains voltage a fuse may still not save the device.
 

Offline kosine

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Re: EEVblog #1160 - Weller Responds
« Reply #186 on: December 19, 2018, 02:55:39 pm »
May be different elsewhere, but 110V tools are actually quite common in the UK, even though our mains is 240V.

110V tools are used on construction and building sites, and have their own style of plug & socket. As a friend recently considered, there's nothing to stop people buying these tools on the cheap and swapping the plug for a domestic one.

Fortunately he asked about it first, but in light of the current discussion, I'm now wondering do these 110V tools have any additional protection in them as standard?
 

Online coppercone2

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Re: EEVblog #1160 - Weller Responds
« Reply #187 on: December 19, 2018, 03:07:10 pm »
whats going to short out at 450W and current limit itself? :wtf

parts are just gonna fail to a happy impedance like that? its probably gonna trip. What part is going to make plenty of smoke like a giant transformer winding dissipating 500W @ 0.3 ohms on a 12V rail?

You've really never seen anything fail in a way that was not a direct, low-impedance short?   :-//

why did it blow the breaker if its supposed to fuse??

Wait...  What?  Who blew what breaker now?   :-//

did you read the discussion? someone said it could deliver 500W before it triggered a fuse. So you would have a short settle down to a stable 0.3 ohms before it tripped the fuse or LVSO ? If it goes under 0.3 ohms you exceed your wattage. What kind of short settles to 0.3 ohms and stays there for maximum power transfer?
 

Offline Grapsus

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Re: EEVblog #1160 - Weller Responds
« Reply #188 on: December 19, 2018, 03:15:32 pm »
From the amazon reviews:

August 7, 2018 : "Only used this iron for less than 2 months before the transformer blew up on me in the middle of an important job. Would not recommend."

https://www.amazon.com/gp/customer-reviews/R2E3U67D56PT9M/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=B077JDGY1J

So maybe they're not using the best quality transformers out there...

Edit: also this one is suspicious

June 25, 2018: "IT STINKS!!

I had to store it outside in the shed when I first got it. It had a strong chemical odor and stunk up the room when used.
The plastic is still out gassing months after I bought it.

Other than that, it's OK."

https://www.amazon.com/gp/customer-reviews/R1T2PUCK5KWZA/ref=cm_cr_getr_d_rvw_ttl?ie=UTF8&ASIN=B077JDGY1J

Sure new plastic items smell sometimes, but this could also be the transformer heating.
« Last Edit: December 19, 2018, 03:24:28 pm by Grapsus »
 

Online coppercone2

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Re: EEVblog #1160 - Weller Responds
« Reply #189 on: December 19, 2018, 03:17:06 pm »
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« Last Edit: December 19, 2018, 04:10:08 pm by Simon »
 

Offline drussell

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Re: EEVblog #1160 - Weller Responds
« Reply #190 on: December 19, 2018, 03:51:27 pm »
Maybe their customers are old-fashioned and think that heavy iron power supply = quality/reliability.

(there's already a few examples of that in this thread)

Are you saying that you have found small switchmode power supplies to be more reliable than a standard transformer?!   :-//
 
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Offline drussell

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Re: EEVblog #1160 - Weller Responds
« Reply #191 on: December 19, 2018, 04:10:30 pm »
(do you own wall warts with huge iron transformers in them?)

Absolutely.  Dozens, possibly hundreds of them.  I can count on my fingers without resorting to toes the number of times I've encountered a failed transformer-type wall wart.  The percentage would be a fraction of a percent of the total I've ever dealt with in my lifetime.

Contrast that with switchmode type wall-wart supplies, plug-packs and inline supplies.  I've seen more like hundreds of failures.  Guaranteed it is a double-digit failure rate percentage on average over the years.  Certain ones I have dealt with approach a 100% failure rate within the type.

Yes, most of these that fail are cheap junk and it is possible to build a good quality switching supply but it seems to actually still cost more than a small transformer type supply that lasts.  Even the best switchmode supplies have been far less reliable than a transformer supply in my personal experience.  YMMV.

I take it your experience is somehow completely different...  ??

Quote
b) The "requirement" will be that that devices fail safely, not that they must have fuses.

The reason fuses are being discussed here is that a fuse would be a cheap way to make Weller soldering stations fail safely. No other reason.

Dave's failed safely...   With a smoke signal saying, "ouch, you hurt me," to boot!  ;)
 
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Offline joeqsmith

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Re: EEVblog #1160 - Weller Responds
« Reply #192 on: December 19, 2018, 04:16:19 pm »
From Rossmann's video,  Pace tweezers may burn your hand if you use them all day...  I really like Pace's MT100 and am waiting to for them to release a version for their new station before upgrading.    Hope their new stations have fuses.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline drussell

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Re: EEVblog #1160 - Weller Responds
« Reply #193 on: December 19, 2018, 04:22:29 pm »
Fortunately he asked about it first, but in light of the current discussion, I'm now wondering do these 110V tools have any additional protection in them as standard?

I believe the idea is that they increase "safety" by supplying the upstream power for these tools from a center-tapped transformer with the center tap grounded, creating a 55-0-55 power supply, keeping the voltage to earth at a safer 55 volts AC from ground instead of 240.
« Last Edit: December 19, 2018, 04:29:32 pm by drussell »
 

Offline drussell

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Re: EEVblog #1160 - Weller Responds
« Reply #194 on: December 19, 2018, 04:28:20 pm »
did you read the discussion? someone said it could deliver 500W before it triggered a fuse. So you would have a short settle down to a stable 0.3 ohms before it tripped the fuse or LVSO ? If it goes under 0.3 ohms you exceed your wattage. What kind of short settles to 0.3 ohms and stays there for maximum power transfer?

I was talking about a PC 12V power supply being able to deliver enough power to create smoke.  Period.  This was a standalone point, not related to any prior specifics in the thread except the fact that some people seem to be implying that no failure of any device may ever be permitted to expel smoke, magic or otherwise.  My point was that attitude is misguided and unachievable.
 

Offline paschulke2

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Offline cdev

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Re: EEVblog #1160 - Weller Responds
« Reply #196 on: December 19, 2018, 05:11:21 pm »
The picture illustrates graphically why soldering stations should ALWAYS be fused, even if increasingly brain dead legislators rubber stamped a likely industry written change that allows them to not fuse some of them.



"What the large print giveth, the small print taketh away."
 

Offline Robaroni

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Re: EEVblog #1160 - Weller Responds
« Reply #197 on: December 19, 2018, 05:18:28 pm »
This is why I retired, people astound me!
Plug a station into 240 volts that's designed for 110 and it burns up. First if they fused the secondary side (I don't know either way) it would still burn up
if you plugged it into 240v.

Did you ever wonder when you see a warning on a package that says something like, "don't put your hand into the flame you might get burned!" And you think who could be so stupid to stick their hand into a flame?  Don't be surprised if you see a warning on Weller stations saying, "Don't plug 120v stations into 240v you could burn up the station!"

So there's smoke, gee I wonder why! I doubt it will catch fire the wire coating is usually fireproof so eventually it will melt away, the primary resistance will drop and the wire itself will melt just like the millions of wall transformers that are not fused.

So the fuse IS the primary winding and if you plug it into 240 you deserve to burn up the station.
I have a $900 Weller station - it will never see 240v. It's electronics it's my field, I'm buying an expensive station!

Let's blame Weller for my stupidity.

By the way it's a great station with long lasting tips in lots of styles.

 
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Offline TheDane

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Re: EEVblog #1160 - Weller Responds
« Reply #198 on: December 19, 2018, 05:22:03 pm »
Must be isolated from mains - expensive

You think switch mode supplies aren't isolated from mains?


I know a lot about switch mode design. I have designed both isolated and unisolated types, and know about each type BOM and cost price.

It is absolutely possibly to make a SMPS that is unisolated from mains, but then there is added danger to the end-user - safety concern, which is also an added expense.  :-//
https://en.wikipedia.org/wiki/Switched-mode_power_supply#Types

Please note the differences between Non-isolated topologies and Isolated topologies
 

Offline Robaroni

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Re: EEVblog #1160 - Weller Responds
« Reply #199 on: December 19, 2018, 05:23:07 pm »
The picture illustrates graphically why soldering stations should ALWAYS be fused, even if increasingly brain dead legislators rubber stamped a likely industry written change that allows them to not fuse some of them.




That would happen regardless if it was fused or not. The fuse would only work if the iron got down to some point on the board where it caused a short. But look at the picture, does that look like someone who should own a soldering station or anything that gets above 20C?

 
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