If you are wondering "How could an isolation transformer ever get past QC with abraded or nicked insulation?", you might find this video interesting:
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.
For them to study, or for them to destroy the evidence so that you absolutely could not take them to court.
Did he miss an opportunity or an opportunity cost?
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.
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.
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.
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.
>Why do you think it's sped up?