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pjvr99

Low Ground Idle RPM

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Hey guys

 

Here's a problem that has me stumped. Engine starts up to LSGI (auto & null TIT peaks

about 810°C). When upshift to NGI engine rpm is 95% and generator will not come on 

line. You need to manually reset ON or move throttle to speed up the engine. All engine 

parameters are good at all throttle settings, IBIT check good. Only GI/FL rpm is

lower than usual, but not out of limit. Generator circuits check good, with all relays,

control panel etc having been replaced, and even generator replaced. 

 

Any thoughts on this issue would be appreciated

 

PJ

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Posted (edited)

The Generator is "offline" below 95% as a function of the frequency sensitive relay so if the rpm is right at the limit to energize it may not, but the FSR relays are known to hold energized once above 95% to a number below 95% SOME say as low as 88% but I have never verified that number as it is impossible to dial down the rpm to 88%

Edited by NATOPS1

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Moeed, it is a zero time engine. 

 

NATOPS1, aircraft is glass cockpit, so I believe indicated rpm to be same as AUTOTACH. It does match

generator frequency. Problem is what to do to get off that 95% GI rpm. Changing the engine only puts

the problem on the ready line for the next time

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Hello pj , when u put the engine to  normal ground idle, Gen frequency on frequency meter available at GEN switch on OFF position.?

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12 hours ago, pjvr99 said:

NATOPS1, aircraft is glass cockpit, so I believe indicated rpm to be same as AUTOTACH. It does match

generator frequency. Problem is what to do to get off that 95% GI rpm. Changing the engine only puts

the problem on the ready line for the next time

Ok got it. ANY pictures? (if allowed)

Guess you can swap out the FSR maybe it has an issue or increase the GI/FI RPM closer to the upper limit.

If you reset the gen will it go on line without speed increase?

if you speed up the engine and get the generator on line will it stay online when slowing back to 95%

 

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2 hours ago, NATOPS1 said:

Ok got it. ANY pictures? (if allowed)

Guess you can swap out the FSR maybe it has an issue or increase the GI/FI RPM closer to the upper limit.

If you reset the gen will it go on line without speed increase?

if you speed up the engine and get the generator on line will it stay online when slowing back to 95%

 

no pics, sorry. swapped out fsr, regulator and control panel - no change. silly question, i know, but ...... how 

do you adjust gi/fi rpm? yes it resets immediately, and will happily stay on line after that, even at low pitch

stop of 93.some %. yes, fsr will drop it out below 365hz. fsr comes on line at 95.2/95.3% which is the

advertized 385hz needed. propeller control is EPCS, so no messing with blade angles

 

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4 hours ago, Ahmer said:

Hello pj , when u put the engine to  normal ground idle, Gen frequency on frequency meter available at GEN switch on OFF position.?

ahmer, this is the problem. we have 380hz/95%, but fsr needs 385hz to engage. fsr is working correctly. engine is also 

working correctly but too slow for fsr.

 

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9 hours ago, pjvr99 said:

ahmer, this is the problem. we have 380hz/95%, but fsr needs 385hz to engage. fsr is working correctly. engine is also 

working correctly but too slow for fsr.

 

Pj, if u change FSR ,AC cont panel and Generator. U should go to Replace FCU because there is no adjustment of GI & FI rpm if prop angle is with in limit. Regard

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OK brand spanking new FCU and GI rpm is 96.2%. Still lower than what I'm used to

seeing, but at least the FSR will engage the generator.

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23 hours ago, pjvr99 said:

OK brand spanking new FCU and GI rpm is 96.2%. Still lower than what I'm used to

seeing, but at least the FSR will engage the generator.

Hi pjvr99, do you have adjusted the LSGI on FCU?

Regards

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Not for this problem Paulo. I have previously had LOW SPEED GROUND IDLE rpm

that was either to low or high. Low GROUND IDLE/FLIGHT IDLE rpm can not be

adjusted on fcu.

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On 5/3/2019 at 2:48 PM, pjvr99 said:

Not for this problem Paulo. I have previously had LOW SPEED GROUND IDLE rpm

that was either to low or high. Low GROUND IDLE/FLIGHT IDLE rpm can not be

adjusted on fcu.

image.thumb.png.1b204f7df47645fb7dca9fe676d31726.png

As you can see the Low Speed Ground Idle is Adjustable on the FCU.

If you have the RPM's very low, you must adjust them between 96.3 and 99.1 for High Speed Ground Idle.

When you adjust LSGI on FCU, it will increase the HSGI.

Regards!!

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Posted (edited)
On 5/10/2019 at 6:42 PM, PauloFerreira said:

image.thumb.png.1b204f7df47645fb7dca9fe676d31726.png

As you can see the Low Speed Ground Idle is Adjustable on the FCU.

If you have the RPM's very low, you must adjust them between 96.3 and 99.1 for High Speed Ground Idle.

When you adjust LSGI on FCU, it will increase the HSGI.

Regards!!

Hi dear paulo, LSGI RPM is 75% & NGI RPM is 95% , what will be ur decision in this situation. How we increase NGI RPM ? Regards 

Edited by Ahmer

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On 5/11/2019 at 6:59 PM, Ahmer said:

Hi dear paulo, LSGI RPM is 75% & NGI RPM is 95% , what will be ur decision in this situation. How we increase NGI RPM ? Regards 

Dear Ahmer,

is a relation of speed and fuel!

More rotation on the Flying Weights of FCU, than more fuel added on both situations!

Regards!

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