January 01, 2004

One of the most important things in this project is how I distribute power 
to the devices that need it.  The simulator will use both AC and DC power 
systems, but since the DC power supplies require AC to run, the AC power 
system will be installed first.

As you might have seen earlier, there are two IEC power connectors mounted 
on one of the new panels that are installed in the new nose section.  
They're there to deliver AC power to this:

The AC outlets are there to supply power to any low-power Wall Wart type 
power supplies that devices like the USB EPIC need.  The terminal strips 
allow a direct connection to the DC power supplies.  The connector board 
is split into two circuits of 15A each as supplied by the two IEC 
connectors on the front of the sim.  The AC BUS on the terminal blocks is 
split into two as well.  The "upper" four are Bus #1 and the lower are Bus 
#2.  The grounds are common to both.

Here's how it looked as the installation procedure began:

It was at this point that I started thinking about power system problems 
and how bad would it get if it really went bad?

I stopped working on the AC system for a week or so while I worked out a 
safer way to bring power to the simulator.  That is one of the reasons the 
Instructor Station was developed.  

I decided that for safety's sake, I was going to install monitor 
indicators in all sections of the power system as well as circuit breakers 
for both the AC and DC power systems.

One of the benefits of this new design was a much neater installation:

This photo was originally taken in November and some changes have been 
made since then, but this still shows how it's going together.

Here's a few pics of the AC Monitor panel as it goes together:

The blue devices are aircraft circuit breakers.  They're nice and small 
and use a 9/16" mounting hole like a standard toggle switch does.  This 
comes in handy when you're drilling a lot of them.

Here is a shot of the panel about 75% complete:

One thing of note here are the two 48V Relay sockets.  They're somewhat 
hard to see, but they're attached to the bulkhead on the right.  They 
control all the AC power that comes into the simulator.  They're activated 
by switches on the Instructor Station.  No station, no power.

Here's a better picture of the relay sockets:

The control wiring hasn't been installed for these yet.

This is actually a pretty good safety feature.  If the main control cable 
from the console isn't connected to the simulator, there's no way that AC 
power can be turned on in the simulator, making it safer to work on.

....and completed! (For the most part)

The monitor panel is designed to tell me at a glance if power is going 
where it should (and if need be, where it shouldn't!).

The tiny toggle switch is used to turn on the rope lighting I'm using to 
illuminate the avionics bay while I'm working in there.  It actually works 
pretty well!

The two small red lamps in the upper left corner of the panel are for
incoming AC power.  They're connected to the input side of the main AC
relays.  If they're on it means the simulator is hot and it's a dumb idea
to go sticking your hands in the area behind the monitor panel.

Once the simulator has been plugged in (thus lighting the two small pilot 
lamps), the AC mains relays can be activated from the Instructor Station.  
Doing this energizes both Bus #1 and #2, illuminating the 5 red indicators 
at the top of the panel.  The 5 red lamps are wired after the circuit 
breakers so if one of the breakers is popped or non-visibly failed, the 
lamp will remain dark.  No light, no power, problem!

At this point, the DC power systems can be activated from the Instructor 
Station.  There are 3 24VDC power supplies and 2 5VDC supplies.  As the 
operator flips the switches on the IS, the green lamps on the monitor 
panel will illuminate.  This tells me that AC power is going to the DC 
power supply that the lamp represents.  The DC power supplies are 
controlled by a bank of 5 48V relays that are installed on the right side 
avionics bay. 

Here's a shot of the relay board with a single relay sitting atop it:

This board is out of position because I was working on it.  It's normally 
installed in the tray mount to the right.  It's marked "APML ELEK CONT".

You'll notice there are 6 relay sockets.  The 6th relay is energized from 
the IS and it in turn supplies AC power to the 48VDC power supply that the 
other relays depend upon.

Here is a pic of the power supplies in their current configuration:

Left to right, you see the 3 24VDC supplies and to the far right are the 
two 5VDC supplies.  The DC supplies all utilize a common ground by 
connecting to the original ground lugs that are present in the avionics 
bays.  The AC grounds also attach to the frame as well.

Another feature that will be part of the IS is pilot lamps that indicate 
that the DC power supplies are functioning.  Look for these when I update 
the Instructor Station page in the future.

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