I love teh 1900

jtrain609 said:
If you leave it on TOO long you can blow the fuse between the gen bus and the battery bus eh?
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If that was the case you would never be able to leave the gens on at all, right?:) Unless I missed something in training( which couldn't possibly happen:D), there is no limit on how long they can be on.

The diff. between the 99 and 1900 is battery starts. The 99 has to have the opposite gen off to start, for fear of blowing the CL, whereas the 1900 gen can be left on for start.
 
I believe the reason is because you're throwing more than 325 amps across the limiter when you're charing the battery back up and that's why there is the 30 second rule with it.

MP explained it to me this way; the limiter is set for 325 amps, but it can handle more than that for short periods of time. So 30 seconds and you're cool, but if you were to charge the battery with the gen for two or three minutes and you'd blow the thing.

But what I do know, I'm wrenching on computer server these days!
 
tinman said:
If that was the case you would never be able to leave the gens on at all, right?:) Unless I missed something in training( which couldn't possibly happen:D), there is no limit on how long they can be on.

The diff. between the 99 and 1900 is battery starts. The 99 has to have the opposite gen off to start, for fear of blowing the CL, whereas the 1900 gen can be left on for start.
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:yeahthat:

The 30 seconds is a minimum, to recharge the battery. The starter draws around 1000 amps initially, and the gen. will try to put out 1000 amps, but like tinman said the 325 amp current limiter would blow.

And for bonus points, when and how are you going to know that you did something wrong?
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Because they are dual-fed buses (talking about the C99), you probably won't even know it until after you shut down or shut off both gens (which you wouldn't normally do). Then when you turn on the battery again, one inverter won't work, if you turn on the avionics half your radios won't work, etc. They get old and blow occasionally, I've had it happen. Just make sure you don't let them load the plane and THEN have maintenance come over to replace it. They are located under the floor in the B bay. :)
 
Is an inverter like a transformer-rectifier (changes AC power to DC)?

I wonder how much my Chinook systems knowledge will help me in airplane-land.
 
jtrain609 said:
I believe the reason is because you're throwing more than 325 amps across the limiter when you're charing the battery back up and that's why there is the 30 second rule with it.

MP explained it to me this way; the limiter is set for 325 amps, but it can handle more than that for short periods of time. So 30 seconds and you're cool, but if you were to charge the battery with the gen for two or three minutes and you'd blow the thing.

But what I do know, I'm wrenching on computer server these days!
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Well if you see Pat before I do, ask him, then let me know. I've got a checkride coming up and that would be good info to know!
 
jtrain609 said:
I believe the reason is because you're throwing more than 325 amps across the limiter when you're charing the battery back up and that's why there is the 30 second rule with it.
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Only if you hit the left starter you are.

MP explained it to me this way; the limiter is set for 325 amps, but it can handle more than that for short periods of time. So 30 seconds and you're cool, but if you were to charge the battery with the gen for two or three minutes and you'd blow the thing.
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Interesting. Never heard of that. If you think about it, that makes no sense. After 30 seconds, the gen. load is below 325 amp and after a minute or two, it's even lower than that. Heck, the gens can only put out 300amps continuously anyways, so I don't know what he's talking about. I don't think it's possible to blow a CL just by leaving the right gen on. Something would have to be seriously FUBAR somewhere.
 
I think you guys are talking about the GCUs. The GCUs desensitize the ties during start so they will allow that large of a draw. Otherwise, the Batt tie HED and Gen tie HEDs will trip at their respective limits for current spikes. On our 1900s, we shouldn't reach the current limit when we bring the right Gen online after a battery start.
 
EatSleepFly said:
Only if you hit the left starter you are.

Interesting. Never heard of that. If you think about it, that makes no sense. After 30 seconds, the gen. load is below 325 amp and after a minute or two, it's even lower than that. Heck, the gens can only put out 300amps continuously anyways, so I don't know what he's talking about. I don't think it's possible to blow a CL just by leaving the right gen on. Something would have to be seriously FUBAR somewhere.
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Couldn't yell ya, but the SOP says to turn off the R gen after 50% or 30 seconds (You're right, whichever takes longer) so that you don't blow a CL (number 7, page 29).

EDIT: In all reality, I'm probably full of it BTW. I still don't know this airplane very well and I haven't spent nearly enough time studying it yet, but I'm trying to figure out why I have this crap in my head.
 
jtrain609 said:
Couldn't yell ya, but the SOP says to turn off the R gen after 50% or 30 seconds (You're right, whichever takes longer) so that you don't blow a CL (number 7, page 29).
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Correct, but the reason is so you don't blow the current limiter by starting the left engine with the right gen. still on. There are no adverse affects of leaving the right gen. on for more than 30 seconds, except wasting time. :)
 
Yeah, whatever is being protected would be long gone after 30 seconds. The worst of the draw is the beginning.
 
jtrain609 said:
Couldn't yell ya, but the SOP says to turn off the R gen after 50% or 30 seconds (You're right, whichever takes longer) so that you don't blow a CL (number 7, page 29).

EDIT: In all reality, I'm probably full of it BTW. I still don't know this airplane very well and I haven't spent nearly enough time studying it yet, but I'm trying to figure out why I have this crap in my head.
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Ah, that might be a SOP to protect the battery or the charging system if the current headed to it remains over 50% after 30 seconds. That shouldn't happen unless you have enought batt voltage for start.
 
EatSleepFly said:
Correct, but the reason is so you don't blow the current limiter by starting the left engine with the right gen. still on. There are no adverse affects of leaving the right gen. on for more than 30 seconds, except wasting time. :)
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Gotcha! Thanks for the clarification. I've gonna have to spend some more time with the tapes/manuals before I do the PIC training!
 
Doug Taylor said:
For a period of time, a lot of Brand-X's training department was filled with "University of Somewhere Where They Put Gravy on Everything" and the "I'm an electron" approach to systems naturally followed them over to Brand-X.
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Darn,
I thought I left that at the university!

BCTAv8r said:
What kind of checks are there to make sure that someone doesn't just memorize the information for a test?
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Recurrent training.
 
Seggy said:
4) No idea MM told me about it at Skyway. I would like to know though!
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On your EFIS display control panel the knob you use to set your DH/MDA is also a test button -

Push the EFIS test on the panel that you use to turn on EFIS to begin with - the one you use to test the EFIS, while holding it push the appropriate DH/MDA/test knob.

You'll get a TAWS terrain terrain pull up or too low terrain warning and your EFIS tubes will go into diagnostic mode.

One page has your roll and pitch and heading information put it's in text like so

Pitch +0.00
Roll +0.00

Heading 015.00

So you can try to fly the plane that way instead of pictorially - which is the normal mode.



The VCM I thought cools to 10 degrees below ambient - which does you little good in Phoenix.

And battery starts is the only way I know how to start a B1900 - I know you can do a GPU start - but none of the GPUs in the company work - so I've discovered with a good battery you can get about 8 or 9 starts out of a battery before it's kaput - the joys of being able to start your engines, but can't get your GEN TIES closed to recharge the battery...

I've discovered, when your red T-handle illuminates in flight - pulling is theoretically supposed to close the fuel valves - no fuel, engine shuts down - well it does, but it shuts down about 45-60 second later. It's much faster to pull your fuel condition lever to fuel cutoff.

Lots of little things learned along the way
 
I am completely clueless to what you are all talking about but it is nevertheless very interesting. Hopefully not too long until I can fly one of these birds.
 
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