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Help With Circuit breakers

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Mitsos1

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Hello All...
Here is my project..im not that good at this but maybe i can get some help..
What im after is this..
In a small airplane where circuits are protected by a CB that pops when a short is detected i was thinking of installing an LED that will be an attention getter,, Flashing is nice but not necessary.

So this is the scenario..
The Aircraft bus voltage is 12 Volt+- .5 or so...
When the CB pops i would like to have a medium size LED light up to attract attention..
Can Someone make up a list of parts and the simplest of wiring to show how to wire it?..
I will use Aircraft wiring to do all that of course....



Thanks To all

Regards
 
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One way to do this is to wire a LED and resistor across the breaker. This limits the current to 10-50 mA through the circuit depending on the LED . What this does mean is that you cannot turn off the current drain for direct battery connected loads.

On the other hand, you could devise a circuit that would draw much less power and be powered by the ignition circuit. Depending on how complex you make it, it could indicate that "A breaker is blown" or you could group them into circuits grouped by importance and use a LED for each group. You would probably have to make a PC board for this option.

We apparently have a pilot as a member of this forum and I'd like to see his take on this.
 
The LED-resistor across the breaker with the anode end connected to the Main Bus, and the cathode connected to the load-end is commonly done. Pick the resistor to limit the LED current (with the breaker open) to ~10mA, and use an ultra-bright RED led. At 10mA, they are bright enough to be noticeable even in sunlight. If the load has an ON/OFF switch (say a Transponder), and the switch is turned off, then the LED will not light even if the breaker is tripped. There is a work around for this; parallel the load with a 1K resistor.
 
All very good ideas...
i will mull over this and see if this is a good idea for me to tinker with ...since an inflight fire is not a pleasant thing LOLLLLL

can u draw a diagram?

there is a master avionics switch that turns power to all avionics...then each circuit has its own CB...ie hydraulic pump a 30 or 40 Amp CB pullable the rest of CB's are not pullable but resetable(not that you would reset in flight but in the event it is an absolute need to complete a flight...
thanks guys...
It has been a while since i did electronics/electrics...

Much appreciated
 
The LED thing is really simple. You can get LED's with a built in resistor so it operates at 12V and it contains flexible leads so there isn't anything wierd that you have to do.

The second idea basically involves n comparitors or OP amps that are wire OR'ed to a LED. The reference would just be a voltage divider on the 12V or an active reference for some voltage like 10V. The inputs would need a resistor to bleed off the input bias current and a comparitor/OP amp would have to be selected such that it could accept a voltage less than the supply voltage without damage.
 
Here is the LED wiring:

In 25 years and 4300 hours of flying, I have only had breakers trip twice. Both times it was a non-event. The P&B Breakers in the Cessna pop out a plunger, which can be felt with the hand, even in the dark. Frankly, rather than worrying about indicators for tripped breakers, it is much more important to have an indicator on things that shouldn't be left on, like boost-pumps, or starter motors (welded contactor), or things you have forgotten to turn on, like the alternator field switch.

I assume you are homebuilding. Have you visited Aeroelectric?
 

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Once again thanks guys ..I appreciate this..
Great site....

Mike its not a homebuild...:)
its a commander single retractable....
Sometimes i wish i was in to homebuilding much more flexibility and cheaper...


Regards
 
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