Don't worry, its OK (Magic of HIGH VOLTS)
avi8tor50 said:
I recently purchased shielded strobe wire and was sent same as you, 3 conductor 18 g. Trouble is, if you're running wires out to the wings from the high power strobe source, I believe you need 16 g. Please correct me if I am wrong. Would appreciate a source of 3 conductor 16 g shielded wire.
Why? Home building is about learning, so its a good question, but think about this, this is what the strobe manufactures and plane manufactures use to route power to strobes in wings and tails of GA plane for decades. With that said Whelen sells 16 ga wire cables, at least today.
Its VERY high volts, not current**. Are you worried about loss (voltage drop)? You are not running continuous high current. 18 g is plenty for an intermittent (hi-volt) service. Its just a fraction of a second on and seconds off, so heat is not an issue.
Also the wire run lengths (20-30 feet) are fairly short, so volt loss is small. Why re-invent the wheel? Just use what they sell you. You are right however, you would have less loss with the larger wire. However the affect on the light output will not be significant, unless you are running long wires.
** The electric company's "grid" starts out typically at 110kV to 220kV (220,000 volts) and drop down several times to 33 kV to 115 kV, than before your house drops to (3.3 to 25 kV). Finally, at point of use, energy is transformed to low voltage (100 to 600 V), varying by country and customer requirements.
Why HIGH volts? Less loss. That is why larger aircraft use 28 volt or even a 46 volt DC electrical systems, they are more efficient. In larger jets they actually use AC with voltages up to 400 volts, which is even more efficient. However there are much longer wire runs and demand on a Boeing 747.
For power: voltage times current. That's why: W(att) = V(olt) x A(ampere)
If the current is doubled, the energy loss quadruples. So if you need 1000 watts power its more efficient to send 1000 volts at 1 amp than 1000 amps at 1 volt.
I don't know what the Volts are coming out of the power supply, but the power in is about 75-150 watts (@ 12 volts)! So if it steps up volts there would be a nasty shock coming. It also depends on flash rate. They rate the energy out as Joules which is: Joules = watts x seconds, therefore watts = joules/seconds.
Some things like starters NEED current and lots of it. Your starter NEEDS something like 2 awg. Why? Its VERY high current (up to/over 300 amps @ 12 volts) and it's continuous, at least for short periods. However lets say you wanted to run 300 amps continuously, you would have an even larger cable by several sizes, like OOO or OOOO gage (about 7/16" diameter wire + insulation). That is why you should not crank your engine continuously or for several long cranks without cool down time between. The starter windings get even hotter. Follow the manufactures DUTY times carefully. What if you use 4 awg? Well the wire will just get hotter and you will have more loss (voltage drop). Heat is the lost electrical energy turned into heat and not work.
Home building and plane design in general are always a series of compromises. You can always go to higher gauge wires, but the plane has to fly and weight and cost go into the design parameters. Usually wire gage is based on voltage drop and/or temp rise for a given service requirement (volts/current/duration). Than the installation, length of wire run and if its bundled with other wires (large thumb sized assemblies not a few wires together) factors in. Finally there is MIN gage (for durability and ease of installation).
