Re: Pilots, how do you do this?
|
Great. I'd like to see his perspective. Thanks for responding. Obviously this would only apply if there were a separate alternator switch. Does not apply to older systems with a generator.? Mike
That could be an interesting thought if you were also in an emergency situation attempting a restart in the air. I actually might ask a mechanic about this at Star and see what they say. Blake Shaner
Phone: (540)855-4331 ¡°Many of life¡¯s failures are people who did not realize how close they were to success when they gave up.¡± ¨C Thomas Edison ? I haven't put much thought in this but makes sense to me. I may rethink starting procedure when situation allows. Especially when the battery is weak or very cold conditions. This is text from the book Aircraft wiring guide. I have it because of my Zenith project in which we will be moving the battery from behind the seat to the firewall and exploring a backup battery location. It could already be a checklist procedure for your aircraft but I like the explanation. 4.7 When to Turn on The Alternator......A question that comes up is whether to turn on the alternator before engine start. Many pilots have a preference based on what they've used to over the years. From an electrical perspective, having the alternator on during engine start does not do anything other than draw current. When the engine is OFF, and the alternator is ON, the voltage regulator sees low bus voltage (about 12.4 volts) and tries to raise the bus voltage to 14.2 volts by increasing the output to the field wire to its maximum capacity. Because the engine is not turning, nothing happens and the voltage stays at 12.4 volts while the voltage regulator is at maximum output, drawing about 4 amps of current. This also makes the alternator harder to turn and adds drag while the engine is starting (how much drag is added, I don't know). Based on this assessment, I don't recommend turning on the alternator until after engine start. Get the engine running, then turn on the alternator, then turn on the avionics. Certain lore says that turning on the alternator when electrical loads are turned on is a bad idea, but I¡¯ve never heard of any problems from customers and the alternator manufacturers I¡¯ve talked with don't see this as a problem.
?
|
