2 ms·
Sometimes even a well designed and assembled power supply can be dangerous because of defective components. Big Clive on Youtube does many teardowns of cheap el
by mrob 11y ago
Sometimes even a well designed and assembled power supply can be dangerous because of defective components. Big Clive on Youtube does many teardowns of cheap electronics, and here's one of a USB power supply that's dangerous because of internal damage to the transformer:
https://www.youtube.com/watch?v=3Hdn0MuCK_0 https://www.youtube.com/watch?v=3Hdn0MuCK_0
Because this is an intermittent fault it's possible that non-destructive testing would not find it.
- Obi_Juan_Kenobi 11y agoThat's not a random failure, though. The quality control for the transformer manufacturing was inadequate. This wasn't some difficult to anticipate error, either; maintaining the integrity of the winding insulation is basically the most important thing to monitor. The machines were either poorly designed or improperly operated. Sourcing higher quality components would prevent such issues. I'll concede that nothing can be perfect, but this type of error is preventable. It starts to cost quite a bit when you move from 0.1% error to 0.01%, though.
- tsomctl 11y agoIt's not just quality control on the part of the transformer manufacturer. It was a cheap design. They could've completely isolated the two transformer windings, either with heavy tape, or wound them on two separate bobbins. That way, if the enamel on the wire wears off, the two sides are still completely isolated. I still agree with your conclusion, though.
- aembleton 11y agoThey might not have been built by machines. Here's a video of those transformers being made: https://www.youtube.com/watch?v=HEJn74Z3wHk https://www.youtube.com/watch?v=HEJn74Z3wHk