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A Little Diode Problem. August 24, 2011

Posted by phoenixcomm in DIY Aircraft Cockpit, Power Systems, TinyCAD.

The other day I was asked:
“Anyone have a tip on what diode I would need for a DC 24v light bulb project? I have two generator lights and a bus tie light, the

Simple Solution, but not really the right one.

bus tie should come on if either gen light illuminates. I want to run power from each gen light to the bus tie light so that if a gen light comes on the bus ties will also illuminate. The diode is needed to keep the other gen light off unless the computer output activates the other gen light.”

Now this is really not what you want to do in a simulator. Here are some more things to think about:

  1. Ground Power
  2. Generator, ON/OFF Switches ( if you are using a alternator most likely you must have a switch to turn off the field winding)
  3. Tie Switch, ON/OFF (two connect the right and left generators together.
  4. The Ground Power – Alternator Field Switch is a DPDT with center OFF
  5. Failure Modes
  6. Indicators for the pilot (both states)

Simple Twin Wiring

Simple Twin Wiring based on my plane phoenix2000 which I have been working on for years. It was supposed to fly in 2000 but never happened, as I ran out of cash, house and other things, so next best thing is build a simulator of it.

So has you can see we have a ground cart plug.  The wire from Switch 2A goes to the ground cart and when it is running pulls in the ground power contactor.

Switches 1B, and 2B turn on the Alternator Field winding’s.

Switch 3 is to turn on the tie buss.

You would also need a battery buss which the following is connected:

  1. Battery
  2. Right and Left Alternator Fields Power (goes to the switches)
  3. Right and Left Starters via their own contactors.
  4. APU or RAT(if you have one)

All status lights should come from the computer.

All relays are really controlled from the computer, in this way you can induce failure modes.

And you might want to have a Volt meter on a switch so you can see whats going on. Also I also have a Amp meter on the two main buses. Remember that this is a SIMPLE system and does not have any 400hz stuff which just adds to the mess. And of course don’t forget about your Circuit Breakers which any plane has loads of.

Oh yes I have to put a plug in for TinyCad for doing all your drawings and yes its a free download. http://sourceforge.net/apps/mediawiki/tinycad/index.php?title=TinyCAD


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