3412 gas generator

[maximi]

I HAVE PROBLEM THAT ACTUATOR LEVER IS QUITE FOR SOMETIME AND THAN IT STARTS TO MOVE UNSTABLE MAKING RPM GO UP AND DOWN, I REPLACED NEW ACTUATOR SAME THING, BUT WHEN I PUT FINGER ON ACTUATOR LEVER IT STOPS SHAKING AND IT IS OK FOR SOME TIME
WONDER IF THIS COULD BE PICK UP PROBLEM OR EVEN PROBLEM WITH WOODWARD CONTROL SHARE LOAD UNIT, REST GENSETS ARE OK, AND ALL OTHER COMPONENTS LIKE WIRING HARNESS, MAGNETO AND REST, I HAVE NOT CHECK PICK UP YET, BUT ACTUATOR IS OK
DID ANYONE HAD PROBLEM LIKE THIS

 

[patprimmer]

You seem to have another problem, like your caps lock is stuck.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[maximi]

can you be more specific please

 

[patprimmer]

It now seems to be fixed

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[catserveng]

The most common cause of atuator "jitter" is the gain adjustment on the governor is too high, it can be stable then when something happens requiring a fuel rate change the actuator can jitter for quite some time.

I'm assuming you have a stock G3412 with a Woodward EG3P actuator driven by a Woodward electronic governor like a 2301A.

Other possible causes,

Unshielded actuator cable or a damaged shield, allowing noise on the actuator signal.

Actuator mechanical problem (not likely since you say it happens same with another actuator).

Actuator drive problem, not likely but does occur once in a while. With actator removed see if there is any play in the actuator drive coupling, should be very little.

Knowing what governor you have and it's settings may get you a better answer.

Hope that helps.

 

[maximi]

still problems , Woodward 2301 is unit and actuator 6L2160, when gensets are working in parallel up to 65 % of load it seem to be ok, but when we put 800kw number 4 start to jump up to 30-50 kw constant, we check the engine it is ok, alternator is ok,
wonder did anyone have problem with jumping actuator like this

 

[catserveng]

OK, so you checked the other things discussed above? Did you check the magnetic pickup, cleaned it and made sure it was correctly adjusted (turn in until touched flywheel ring gear and back our 3/4 to 1 turn)

According to your latest post, it appears stable until you reach a certain load point on the engine, at point of engine rated load in percent does this occur? You say 800 ekW, across how many engines?

A higher load actuator instablity is usually an indication of misfire. Is the engine equipped with exhaust port pyrometers? If not, how do you verify cylinder operation? A timing light or firing indictor? Watch the actuator, does it quckly go to FUEL ON, then towards FUEL OFF? Or the otehr way around?

 

[CH5OH]

a hunting governor:
at one hand your governor should react fast enough to deal with load changes, on the other hand it shouldn't react that fast that it becomes unstable (hunting)
if it is an electronic governor there should be a regulating point for this, with a hydraulic governor there is somewhere a needle valve,which you open more until it starts hunting, then you close it about a half turn

 

[maximi]

so we have 4 3412 engines gas natural, all engines are ok and alternator as well are ok, now g1 g2g3 are working fine,g1g3g4 are working also fine in parallel but for some reason when in combinations are g1g2 together they start to oscilate above 65 percent of load
now it is wierd but looks like G2 and G4 do not stand ok together, why system starts to oscilate above 65% of load, the G4 oscilates like 40 kw at time ramping up all time , and now when we mowe to actuator lever with finger slowly we can ease down this ramping to zero,
so no load is ok but when we get above this percentage load it starts to be unsatble actuator on G4

 

[CH5OH]

so if I understand it correctly, you have 3 gensets which work properly on 800kW, I don't know the load curve of a
3412 but it sounds like close to maximum power so may be the turbo's having the hick-ups any differences there compaired to the other gen sets (inlet filters, turbo outlet temperatures,rpm,noise,...) when running on same load?

 

[catserveng]

You know, I used to make a lot of money working on engine generator controls when the engine was "good".

A few more specifics would help. Are you using 2301A load sharing governors? Or 3201A speed controls with another load share module? If so, what type?

Are the governor settings for Gain, Reset and Compensation about the same?

Is someone there knowledgable on how to adjust load gain on the load share portion of the governors?

Ideally the load gain voltage should be 6 VDC at full rated engine load. This is proportional so if you put 50% load the signal should be 3 VDC.

When the engines indicate equally sharing electrical load, do they have the same actuator position, manifold pressure and throttle angle? If not they are not properly tuned.

How are you determining "engines OK"? How long has problem been occuring? How long since major maintenance, like top end or overhaul.

Are these older 3412's with the magneto in the vee of the engine? This was a typical failure mode of the magneto due to excessive heat, at higher loads the engine would start to miss, when it got bad it would backfire and may blow the carburator apart.

Other possible causes of higher load instability,

Carburator diaphragm guide wear
Throttle shaft binding in bearings (worse with needle bearings)
Gas fuel regulator internal linkage worn (lever and post interface, or valve stem binding in housing)
Wastegate shaft binding
Intermittant ignition component failure, such as magneto, coil, spark lead or extender and spark plug.
Improper valve and bridge adjustment
Improper air/fuel ratio setting

If these are 60Hz machines they are likely rated at 325 or 375 ekW. What is your engines ratings? Do they have catalytic convertors?

Any otehr details you have can help provide better answers.

Hope that helps,

Mike L.

 

[CH5OH]

important to know is the boundries of the failure: oscillating problem if >60% load with nr4 or
oscillating problem if >60% load with nr4 in parallel with nr 2

i guess the gensets can't be loaded separately?
just a hunch:
from the four gensets nr2 has the highest voltage droop and nr4 the lowest (the amount the voltage drops on the generator terminals when the load increases,eg set screw on voltage regulator)
compaired voltage droop:
G4>>G1=G3>G2

failure mechanism:
power demand increase <60%
G4 produces higher voltage than G2
G4 load increase, G2 load decrease (G4 icrease>G2 decrease)
G4 governor compensates,G2 voltage increase (less load, less voltage drop)
...