An inductor has rated operating voltage (across inductor) = 75 V. Suppose 100 V comes across it for some microseconds (~ less than 1 us). What will happen? Is the operation dangerous in such cases? I usually don't hear about voltage ratings for inductors thus the confusion.
Here is the datasheet for the inductor where it is mentioned: https://www.vishay.com/docs/34350/ihlp8787mz5a.pdf
This 75 V is a rating.
It's important to understand what a rating is. It's a statement that if you operate at or below that, the manufacturer is assuring you that it's extremely likely that the part will keep working.
If you're a professional, or designing equipment that's to be mass produced, you need to keep within ratings. Ideally, stay well inside ratings. If the thing stops working, and you're the guy that chose to operate something beyond its rating, you are going to get blamed.
So why have they chosen 75 V? That's probably the rating (that word again) of the insulation on the wire it's wound with. The inductor manufacturer probably doesn't make their own wire, but buys it in from elsewhere, and simply repeats the wire ratings.
What's going to happen if you apply 100 V across it? The wire insulation will probably survive. In fact, within reason, if a polymer insulation is thick enough to be mechanically robust, it's thick enough to withstand 300 V. If you remove the high voltage quickly enough that the current doesn't rise or stay high long enough to give you a thermal, heating, problem in the wire, then you're probably good.
Zap one to see what it takes to break it by all means. But for a quiet life, don't invite extra possible sources of failure into your design, and stay within the ratings.
Suppose 100V comes across it for some microseconds
The rated voltage (75 volts) is specified in the data sheet for all inductance values in that product range hence, it seems likely that going to 100 volts might exceed the maximum permissible voltage rating. However, this maximum is not stated so, you should contact the supplier rather than base any judgements using faith alone.
What will happen? Is the operation dangerous in such cases?
Probably nothing bad but, can you take the risk that overheating or some other kind of breakdown might start a fire?
I usually don't hear about voltage ratings for Inductors thus the confusion.
Yes, it's really annoying that this isn't detailed in all data sheets.
