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If you are wondering "How could an isolation transformer ever get past QC with abraded or nicked insulation?", you might find this video interesting: https://w

If you are wondering "How could an isolation transformer ever get past QC with abraded or nicked insulation?", you might find this video interesting: https://www.youtube.com/watch?v=HEJn74Z3wHk https://www.youtube.com/watch?v=HEJn74Z3wHk

LeifCarrotson 11y ago
You can still run those through a bed-of-nails tester to verify insulation, continuity, and pinout.
- marshray 11y ago
  Yeah, that will catch a lot of direct shorts and opens but some problems just don't show up until the device has been thermally cycled and baked in for a few thousand hours of usage. It's also possible that there was another problem in the circuit which caused overheating in the transformer.
deleted 11y ago
[deleted]
digi_owl 11y ago
The cost of us wanting everything cheaper, and yesterday...
drauh 11y ago
That seems sped up, like a 1920s movie.
akurilin 11y ago
I've had a portable Bluetooth speaker blow up in my bedroom a couple of years ago while charging. Something malfunctioned in the battery section. The only reason that didn't set the building on fire was that I was right next to the speaker when it burst into flames. My immediate reaction was to assume my SO playing a really unfortunate firecracker prank on me, but half a second later it was obvious it was the speaker's fault. Turns out batteries can make pretty flames and a lot of fairly unpleasant smoke. To this day, still can't believe how lucky I was to be right next to it with a pillow as it blew up. The company was kind enough to send us their top of the line product for the incident, in exchange for the faulty unit (for them to study) and a written agreement to not take em to court. Still pretty uncomfortable around charging devices with batteries to this day, but the reality is that it's unavoidable and there's no point in developing a phobia about it.
- GigabyteCoin 11y ago
  >for them to study For them to study, or for them to destroy the evidence so that you absolutely could not take them to court.
  - RickHull 11y ago
    > so that you absolutely could not take them to court. Did he miss an opportunity or an opportunity cost?
    - GigabyteCoin 11y ago
      He's the poster child for a potential class action lawsuit. He witnessed their product explode with his own eyes. And yes I would imagine that there could have been some cost associated with cleaning up the smoke smell left in the room and possibly any burned areas.
    - cm2187 11y ago
      I wish their was a class action every time a developer leaves an unpatched bug in their software...
13of40 11y ago
I don't get it. They made transformers like that for about 80 years in America, but if a Chinese person does it, it's crazy and dangerous? It looked like she was doing a pretty good job.
- marshray 11y ago
  Nobody said anything about America or China. The listed uploader on the video even suggests it's from India. So quit yer trolling. The transformers made 80 years ago were indeed dangerous. Generally they used paper insulation soaked in fire retardant chemicals. There are a couple of observations I make about this video: 1. She's working amazingly fast and clearly with great skill. However, there's very very little time being spent inspecting the result at each stage. 2. Observe that she is holding sharp wire cutting scissors in her hand as she performs many operations on the insulating tape and wire. It would be extremely easy to accidentally nick the insulation when working at that speed. This insulation is the only barrier between your charging iPhone and the 120/240 mains voltage (or higher in a switching supply). 3. This transformer design is not the safer more modern "split bobbin" type as suggested in the original video. Instead of having a plastic barrier between two separate windings, it relies entirely on the enamel insulation of the transformer wire and a few layers of insulating tape between concentric windings. The precise number of insulating tape layers is essential to achieve the necessary safety insulation. The white tape wound along the sides is important too. Watch the video again closely. How careful is she being to count the number of layers of insulating tape? It's possible her winding machine is counting them, but this step flies by so quickly it's a bit worrying. Edit: This may be extrapolating a bit because it may be we're seeing the outer, rather than an interposing, layer of tape being wrapped in the video. 4. The transformers are piled haphazardly as they are being constructed. They are heavy and the bottom pins can have get a pretty sharp point on them. I bet some of those transformers at the bottom of those piles are getting their insulation punctured.
  - Symbiote 11y ago
    (She speaks Mandarin, briefly, so this is very likely China.) It's amazing though! Working that fast. It's also just what the client ordered, if they wanted better quality they'd have to pay for it.
ktRolster 11y ago
I think that video has been sped up somewhat....
- DanBC 11y ago
  Why do you think it's sped up? There's surprising amounts of skill in these unskilled / semi-skilled jobs. If you're sitting at a machine winding transformers for 8 hours a day, and paid for each item you make (and fined for each item that fails test) you quickly get faster at winding transformers.
  - ktRolster 11y ago
    >Why do you think it's sped up? Primarily because of the extreme precision when moving the arm over a long distance

LeifCarrotson 11y ago

You can still run those through a bed-of-nails tester to verify insulation, continuity, and pinout.

marshray 11y ago
Yeah, that will catch a lot of direct shorts and opens but some problems just don't show up until the device has been thermally cycled and baked in for a few thousand hours of usage. It's also possible that there was another problem in the circuit which caused overheating in the transformer.

deleted 11y ago

[deleted]

digi_owl 11y ago

The cost of us wanting everything cheaper, and yesterday...

drauh 11y ago

That seems sped up, like a 1920s movie.

akurilin 11y ago

I've had a portable Bluetooth speaker blow up in my bedroom a couple of years ago while charging. Something malfunctioned in the battery section. The only reason that didn't set the building on fire was that I was right next to the speaker when it burst into flames. My immediate reaction was to assume my SO playing a really unfortunate firecracker prank on me, but half a second later it was obvious it was the speaker's fault. Turns out batteries can make pretty flames and a lot of fairly unpleasant smoke. To this day, still can't believe how lucky I was to be right next to it with a pillow as it blew up. The company was kind enough to send us their top of the line product for the incident, in exchange for the faulty unit (for them to study) and a written agreement to not take em to court. Still pretty uncomfortable around charging devices with batteries to this day, but the reality is that it's unavoidable and there's no point in developing a phobia about it.

GigabyteCoin 11y ago
>for them to study For them to study, or for them to destroy the evidence so that you absolutely could not take them to court.
- RickHull 11y ago
  > so that you absolutely could not take them to court. Did he miss an opportunity or an opportunity cost?
  - GigabyteCoin 11y ago
    He's the poster child for a potential class action lawsuit. He witnessed their product explode with his own eyes. And yes I would imagine that there could have been some cost associated with cleaning up the smoke smell left in the room and possibly any burned areas.
  - cm2187 11y ago
    I wish their was a class action every time a developer leaves an unpatched bug in their software...

13of40 11y ago

I don't get it. They made transformers like that for about 80 years in America, but if a Chinese person does it, it's crazy and dangerous? It looked like she was doing a pretty good job.

marshray 11y ago
Nobody said anything about America or China. The listed uploader on the video even suggests it's from India. So quit yer trolling. The transformers made 80 years ago were indeed dangerous. Generally they used paper insulation soaked in fire retardant chemicals. There are a couple of observations I make about this video: 1. She's working amazingly fast and clearly with great skill. However, there's very very little time being spent inspecting the result at each stage. 2. Observe that she is holding sharp wire cutting scissors in her hand as she performs many operations on the insulating tape and wire. It would be extremely easy to accidentally nick the insulation when working at that speed. This insulation is the only barrier between your charging iPhone and the 120/240 mains voltage (or higher in a switching supply). 3. This transformer design is not the safer more modern "split bobbin" type as suggested in the original video. Instead of having a plastic barrier between two separate windings, it relies entirely on the enamel insulation of the transformer wire and a few layers of insulating tape between concentric windings. The precise number of insulating tape layers is essential to achieve the necessary safety insulation. The white tape wound along the sides is important too. Watch the video again closely. How careful is she being to count the number of layers of insulating tape? It's possible her winding machine is counting them, but this step flies by so quickly it's a bit worrying. Edit: This may be extrapolating a bit because it may be we're seeing the outer, rather than an interposing, layer of tape being wrapped in the video. 4. The transformers are piled haphazardly as they are being constructed. They are heavy and the bottom pins can have get a pretty sharp point on them. I bet some of those transformers at the bottom of those piles are getting their insulation punctured.
- Symbiote 11y ago
  (She speaks Mandarin, briefly, so this is very likely China.) It's amazing though! Working that fast. It's also just what the client ordered, if they wanted better quality they'd have to pay for it.

ktRolster 11y ago

I think that video has been sped up somewhat....

DanBC 11y ago
Why do you think it's sped up? There's surprising amounts of skill in these unskilled / semi-skilled jobs. If you're sitting at a machine winding transformers for 8 hours a day, and paid for each item you make (and fined for each item that fails test) you quickly get faster at winding transformers.
- ktRolster 11y ago
  >Why do you think it's sped up? Primarily because of the extreme precision when moving the arm over a long distance