7i76e burned - after setting up VFD

Thank you guys.
Its sure that i will never ever again do that, not even on other electrical devices, but i would like to understand why that kind of ?voltage? peaks happening?

I have tried to google that, but i think i am entering the wrong keywords. I dont expect to get an explanation, but it would be if you could tell me how to find informations about that.

Thanks in advance.

Basically if you have electronic devices with DC power
(say a power supply and a motor drive) Both devices will have
likely have bypass capacitors. So if you connect one device that is charged
(say a power supply) to a device with 0 voltage across its
capacitors, a large surge current will flow between the capacitors
limited only by the capacitor internal resistance and wiring inductance.
This can cause current surges from the 10s to 1000s of Amps
depending on the capacitors, wiring and voltage difference.
The current surge can also cause a voltage surge because
of stored energy in the wiring inductance.

You would think that internet has answers to any question, then i can not find anything useful about this.
This has some info about not switching the DC side of electronics:
www.google.com/search?ei=fgUSX-udEO6Bk74...yjChMQ4dUDCAs&uact=5
The top 3 results and another lower link to Kollmorgen.
I am sure that is true for all the electronics that have inductive loads on them, any switching of the DC side will end up in smoke if they are powered and enabled. I am also sure all chips have a rate at what the voltage supplying them can rise, but i will leave this to PCW as he is the ultimate expert on these subjects.
Ha, to late, was searching and finding nothing useful.
Thank you PCW.

It makes totally sense for me. Especially after i have read about what are bypass capacitors
Thanks!

Isn't this a sign of bad design, i mean most modern electronics have protection for about everything. A switching power supply for example doesn't simply go dead just because you short the outputs unless you get some really crappy stuff. MESA with their experience and reputation should now and do better than that.

Just a thought/Stefan

In general you cannot switch the DC power to power electronics because of the surge currents involved. If you switch the DC power to a step motor drive or a DC powered servo drive you will have trouble. The 7I76e outputs are protected against overloads but you can still cause issues by live switching the field power.

Yes but still..

OK as an experiment, you might try say plugging in the DC power to your step motor drive live...

I'm actually using and tampering with a lot off electronics and up to now I have never had any issues switching dc side on any raspberry Pi, ESP8366, Arduino ....

Yep those are 5V or lower voltage powered, not power electronics, big difference