Sort of. The GCU protects against under/over voltage and frequency. I cannot remember the percentages off the spec values of 115 Vand 400 Hz, been too long since I had to memorize them.

When you power up as you described, the GCU will keep power off the plane until the undervoltage and underfrequency values are passed. What you'll see/hear is a lower voltage than normal, but it's not like you will see the voltage rise from 0 to 115 V. Probably more like 95 V to 115, but that's a quick second. Same thing if you shut off the APU first then the generator. You'll hear the electric flow and see the lights dim until the GCU disconnects to save the avionics and such.

In operation, the GCU senses a power drop, allows more voltage to pass from the PMG (Permanent Magnet Generator) built into the generator back into the GCU and then into the windings of the generator, which then increases voltage output of the generator to meet the demand. That's how we are able to maintain volts and hertz at such a small range of fluctuation as loafs change.

Hopefully that clears up any previous confusion I may have caused.

And as for the previous poster who said that the green light means power is good after the GCU... not quite. It just means there is power at the external power monitor panel. As in available for the GCU to check it when you press the switch in. Push the switch with "bad" power, and the light stays green, but the GCU won't allow power to travel thru it to the plane. Similar to the light on a power strip when you plug it into the wall; it means that power is there, but unless you plug in your device, no power is flowing anywhere.

 

As electrifying as this conversation is I think we have beaten this dead horse enough.

On a completely unrelated note; could someone please tell the curriculum developers to remove the mic from their throats when they are doing the voice overs for the LMS modules. Many thanks.

 

Well that's certainly more in depth than I've learned since I stated flying it, but you can burn up electrical components with under amperage. I had to look it up, but the poster would have to know that the current amperage demand is under 150 if the apu is running, plus what the engine gen is producing at the time the GCU allows it pass through. Or he'd just be relying on circuit breakers popping. Granted it would have to be under a heavy draw. I apologize for an impolite comment regarding his knowledge, but a successful engine start with gen switch on in no way validates it as harmless. Even with the GCU monitoring volts and hertz.

 

I just looked in the 200 ODH and, it says on page 47 to turn the AC Power switch off after a huffer start.

 

FFS, just do what the book says. Don't try to second guess Bombardia engeneers, or the company and do your own thing. If it becomes a problem I'm sure they'll revise the CFM. But I can say this, I've been flying CRJ's for a long time and I've never heard of any problems coming from leaving the External Power Switch on. Nor have I ever heard of anyone getting electrocuted while plugging it in. Ground procedures are to turn on the power after it's plugged in

 

If the pressing of a switch is the most important topic to discuss then things must be going pretty well here.

 

Keeps you distracted from the probable pay cut coming...

 

No way the company would allow this to happen. They care about us too darn much. I foresee not only a pay raise coming, but a new type rating as well.

 

I was pivoting off your comment to make a general statement about where the thread has gone....i make no judgment on the veracity of your comment.

 

All due respect, but you are mistaken about them caring about us too much. This company is night and day different for the better from a few years ago, but they have only upped our pay because they had to to keep us staffed. No airline pays any more than they have to out of benevolence. They pay what the market demands.

The word in recurrent from one of the guys on our negotiating committee was a $19 per hour for everyone and do away with the bonus completely. That's a pay cut for anyone who credits less than 85 hours per month. Not a single pilot should suffer any cut in pay, period.