SeanB's USB charger transient tests

[joeqsmith]

2.5, 3, 4 and 5KV.  Notice the output seems fine.  Again, this generator can not put out very energy.       We can see the load it really having an effect on the decay time.  I am sure if someone was smart enough to think I was directly coupling capacitors into the meters when I test them, someone else equally as smart is going to somehow think this has something to do with the real IEC surge test, even if I say it's not even in the ball park.    Those meters you see on Fluke and Gossen's websites don't explode for lack of energy.     

So I'm not sure what we learned from this or even if this was SeanB's goal. 

About the only other thing I could do is apply a transient from the half cycle line simulator.  Originally when I started working on that design, it would have been a decent setup for this test as I was targeting a typical house wiring at the junction box.   But things evolve.   So if you want to see it, I'll get the high speed camera out. 

[SeanB]

Thanks Joe, but not needed, I was interested to see that a device, with a UL marking, that cost $2 retail, could actually be made to survive the pulses that have killed some of the meters you tested.  I guess that the meters are less dangerous though, in that they are not an item that is nearly always plugged in to the power line and expected to survive all the hash coming down.

Thank you for at least entertaining the idea though, and for doing the test. I was interested in seeing that the transformer insulation was capable of handling the pulses without breakdown, which seems to be the most common failure of these chargers, demonstrated by the few examples of people being electrocuted by them during use of the attached phone during charging.

[joeqsmith]

Thanks Joe, but not needed, I was interested to see that a device, with a UL marking, that cost $2 retail, could actually be made to survive the pulses that have killed some of the meters you tested.  I guess that the meters are less dangerous though, in that they are not an item that is nearly always plugged in to the power line and expected to survive all the hash coming down.

Thank you for at least entertaining the idea though, and for doing the test. I was interested in seeing that the transformer insulation was capable of handling the pulses without breakdown, which seems to be the most common failure of these chargers, demonstrated by the few examples of people being electrocuted by them during use of the attached phone during charging.

I would say the meters are potentially MUCH more dangerous than a USB charger than plugs into a wall outlet.  First, we are talking about a CAT II environment versus who knows what.  You can pretty much be sure the charger is never going to be attached to a 480 bus.   Transients in CAT II may have much lower voltage, energy than CAT III.   Most people don't hold the wall chargers in their hand while they are using them.  Wall chargers don't have leads attached to them.  The education needed to use a charger safely versus a multimeter is much less.  How many people do you see post, I hooked my meter to the output of a MOT...  Have you ever seen someone post the same thing for a charger?   List goes on...

For the insulation breakdown what HKJ is doing with the insulation tester looking between primary and secondary would be more appropriate than a surge test anyway.   

And again, to be clear, my generator's energy levels are much less than what you could potentially see on an AC line, even in a CAT II enviroment.  You can't compare the two,  although I am sure there are people out there who feel you can.   It gets back to that was never a goal.   If I wanted to run real line transient tests, I would have a combo generator sitting here with a blast containment setup.   This is the same reason I can't look at your power strips or any other AC device like this.   You think people cry foul about the testing I do now, imagine if they saw all these perfectly good meters coming apart at the seams!     

I know there is a lot of confusion surrounding the meter testing I do.   I've shown  open circuit waveforms, light bulbs, charging capacitors to the same energy levels and discharging them to a metal plate.    Maybe this test will help a few more people understand about what is going on or it will just add to the confusion.       Can I interest you in a slightly used AC USB charger?