> The part might look "wrong" without this information. One case was a 3.15A > fuse in >series with a 27R resistor at the 28V supply input. The fuse can > never blow (no the >aircraft didn't have 115V 400Hz supplies). > The reason was a pater exercise to obtain intrinsic safety approval without > formal >testing. The rules said a specific type of fuse must be used at the > input, the minimum >rating of that approved type of fuse was 3.15A!
I've been down a similar road. We designed a low power radio remote control to run some Coal Mining equipment. The regulatory bureaucrats in the UK Coal Mining industry for intrinsic safety told us we *had* to use a particular power diode, don't recall the number any more, or they would not approve our product. That diode leaked more current that our product took while transmitting! If we wanted to use any modern diode, they would let us do that if we paid them nearly a hundred grand to "get it tested and approved", and listed by them as an approved component. So we used their diode and put up with the constant complaints about short battery life. :-( -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
