Where do you get this? I read the article and it isn't completely clear to me whether the failure of the switch prevented a detonation or if a failure would have caused detonation. My first assumption was that had the switch failed it would have detonated.For those not willing to click the link, a nuclear bomb was dropped in North Carolina in 1961, and this switch failing prevented it from exploding.
So one switch was operating properly, and the other three were not (unless someone armed them for whatever reason).The actual document the guardian links to on that same page says 3 of 4 switches fired. The idea there was all 4 switches had to trigger in sequence to detonate the warhead. One did not. The other three were "set off by the fall."
It's a fancy name for a "motor driven rotary switch". I've no idea what type(s) were actually inside that bomb but these are some common types.So one switch was operating properly, and the other three were not (unless someone armed them for whatever reason).
I don't know what "dynamo technology" means.