757 exit sign voltage
Discussion
Perhaps a strange one but seems the best place to put it!
My sister has bought this for my nephew to make a little display as he loves planes.
Would anyone know what voltage this needed?
It's supposed to be from a 757 and the internet suggests perhaps 28v DC, but I'd like to know for sure before I try anything.
Would imagine given the age it's just a series of incandescent bulbs inside it.
My sister has bought this for my nephew to make a little display as he loves planes.
Would anyone know what voltage this needed?
It's supposed to be from a 757 and the internet suggests perhaps 28v DC, but I'd like to know for sure before I try anything.
Would imagine given the age it's just a series of incandescent bulbs inside it.
Its classed as part of an "emergency" system and the overwhelming majority of those use "raw" 28vDC from the aircraft 28vDC battery i.e. straight from the battery to the device via a busbar.
However, just to confuse the matter - that may not necessarily mean the lighting device itself uses "raw" 28v DC (although thats the most likely), it can also be that the "raw" 28vDC is actually sent to resistor pack to drop the voltage to say 12vDC or 5vDC etc which is what actually powers the bulb inside etc, but the chances of that are fairly small, and its most likely 28vDC.
However, just to confuse the matter - that may not necessarily mean the lighting device itself uses "raw" 28v DC (although thats the most likely), it can also be that the "raw" 28vDC is actually sent to resistor pack to drop the voltage to say 12vDC or 5vDC etc which is what actually powers the bulb inside etc, but the chances of that are fairly small, and its most likely 28vDC.
Went and got it to take a look.
Seems it's 5v at ~1.2 amps, but not quite what I'd imagined inside with the array of tiny bulbs! Nothing in it to drop the voltage I can see without taking it apart more, seems to be just wires straight onto a common bus bar with the lamp holders.
Decided to wire up an old power supply for now (doesn't everyone have a big box full of them just waiting for another job?) and that will keep him happy until they all blow and I can replace with some LEDs.
Seems it's 5v at ~1.2 amps, but not quite what I'd imagined inside with the array of tiny bulbs! Nothing in it to drop the voltage I can see without taking it apart more, seems to be just wires straight onto a common bus bar with the lamp holders.
Decided to wire up an old power supply for now (doesn't everyone have a big box full of them just waiting for another job?) and that will keep him happy until they all blow and I can replace with some LEDs.
LivLL said:
6v emergency light battery packs supply these lights when they're on the aircraft, definitely not 28v direct from the battery bus.
That's a properly cool thing for a kid's room. To be fair, it does say 5V on the unit. Presumably there is some sort of resistive ballast somewhere. They look to be pretty conservatively run (which you'd expect) so they should last a good amount of time on a USB plug pack. Pace soldering iron. Nice!
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