S
GE Model: PG6581(B)
Controls: Speedtronic Mark V <R><S><T>. Can't remember what you call the NOT simplex kind.
Fuel gas skid: Flenco GB DLN1
Part Number: 379A9741.
We're having some trouble holding P2 pressure stable during normal operations. Not sure if turbine generator is causing the swings in the pressure are if the fuel skid is causing the turbine/generator to swing. I'm not saying the DLN skid is the problem, but it's where we're going to start. I've a new field engineer so I thought I'd spend some time working through troubleshooting. He wanted to verify the positioning on the SRV as a first measure. Good deal, smart guy.
We referenced the original control settings. And I quote....
4. SRV Position Calibration:
0% stroke = 0.7 VRMS feedback
100% stroke: (1.25 inch linear travel)
Ok, so no worries. We dig out the old dial indicator and magnet base from back in the log cabin part of the facility and head out to the gas skid. (after blinding off the natural gas of course)
Its a fisher V300 ser B valve. This is a ball valve. Actuated by a Moog contraption (Model 80-113B13CEP)
Question 1. How does one measure linear stroke on a ball valve?
So being confused but determined, we pull out the original papyrus commissioning book, which stated, among other things,
Adjusted LVDT voltages are very close to what I am seeing now. <pre>
LVDT 1 LVDT 2 STROKE
REFERENCE RMS VAC RMS VAC Inches
0% 0.696 0.716 0.003
25% 1.190 1.221 0.978
50% 1.691 1.73 1.989
75% 2.188 2.231 3.014
100% 2.684 2.731 3.949
75% 2.194 2.238 2.964
50% 1.698 1.736 1.991
25% 1.195 1.214 0.995
0% 0.695 0.714 0.008</pre>
Question 2. Why the difference between the linear stroke in the original control settings and the theoretical stroke in the commissioning documents?
Here are the original regulator 1 settings from the good ol' <Q> card.
Regulator Definition for Servo Output 1 90SR-1
Function type & sub-type: 77
Valid types <00, 2D, 2E, 40, 41, 43, 49, 51, 52, 53, 77, 78, 7A, 7B, 7C>
Suicide enable :- Current Fault: NO LVDT/R fault: NO
Suicide position limits (%):: Low: -5.0 High: 105.0
Current Gain: (0 to 200% rated_cur./%pos.) 1.93
Current Bias: (0 to 100% rated [10,20,40]) 2.7
Zero Stroke (0 to 6.667 Vrms) :- LVDT 1: 0.6999 LVDT 2: 0.6999
100% Stroke (0 to 6.667 Vrms) :- LVDT 1: 2.880 LVDT 2: 2.880
<7> Pos limits (-128% to 128%) :- Low: -25.0 High: 100.0
<7> Integrator convergence gain (0 to 16 psi/%): 0.3
<7> Position reference Gain (0 to 2 %/psi): 0.1
Note: for type 5, enter fuel flow data on Pulse Rate screen.
for type 7, enter time constant data on screen #12.
Any ideas? Anyone?
All the original voltages line up with what we are seeing now. The actuator sounds terrible and I suspect a problem there, but we already knew that.
Yes, its an RMS meter. Yes it's been checked recently.
Controls: Speedtronic Mark V <R><S><T>. Can't remember what you call the NOT simplex kind.
Fuel gas skid: Flenco GB DLN1
Part Number: 379A9741.
We're having some trouble holding P2 pressure stable during normal operations. Not sure if turbine generator is causing the swings in the pressure are if the fuel skid is causing the turbine/generator to swing. I'm not saying the DLN skid is the problem, but it's where we're going to start. I've a new field engineer so I thought I'd spend some time working through troubleshooting. He wanted to verify the positioning on the SRV as a first measure. Good deal, smart guy.
We referenced the original control settings. And I quote....
4. SRV Position Calibration:
0% stroke = 0.7 VRMS feedback
100% stroke: (1.25 inch linear travel)
Ok, so no worries. We dig out the old dial indicator and magnet base from back in the log cabin part of the facility and head out to the gas skid. (after blinding off the natural gas of course)
Its a fisher V300 ser B valve. This is a ball valve. Actuated by a Moog contraption (Model 80-113B13CEP)
Question 1. How does one measure linear stroke on a ball valve?
So being confused but determined, we pull out the original papyrus commissioning book, which stated, among other things,
Adjusted LVDT voltages are very close to what I am seeing now. <pre>
LVDT 1 LVDT 2 STROKE
REFERENCE RMS VAC RMS VAC Inches
0% 0.696 0.716 0.003
25% 1.190 1.221 0.978
50% 1.691 1.73 1.989
75% 2.188 2.231 3.014
100% 2.684 2.731 3.949
75% 2.194 2.238 2.964
50% 1.698 1.736 1.991
25% 1.195 1.214 0.995
0% 0.695 0.714 0.008</pre>
Question 2. Why the difference between the linear stroke in the original control settings and the theoretical stroke in the commissioning documents?
Here are the original regulator 1 settings from the good ol' <Q> card.
Regulator Definition for Servo Output 1 90SR-1
Function type & sub-type: 77
Valid types <00, 2D, 2E, 40, 41, 43, 49, 51, 52, 53, 77, 78, 7A, 7B, 7C>
Suicide enable :- Current Fault: NO LVDT/R fault: NO
Suicide position limits (%):: Low: -5.0 High: 105.0
Current Gain: (0 to 200% rated_cur./%pos.) 1.93
Current Bias: (0 to 100% rated [10,20,40]) 2.7
Zero Stroke (0 to 6.667 Vrms) :- LVDT 1: 0.6999 LVDT 2: 0.6999
100% Stroke (0 to 6.667 Vrms) :- LVDT 1: 2.880 LVDT 2: 2.880
<7> Pos limits (-128% to 128%) :- Low: -25.0 High: 100.0
<7> Integrator convergence gain (0 to 16 psi/%): 0.3
<7> Position reference Gain (0 to 2 %/psi): 0.1
Note: for type 5, enter fuel flow data on Pulse Rate screen.
for type 7, enter time constant data on screen #12.
Any ideas? Anyone?
All the original voltages line up with what we are seeing now. The actuator sounds terrible and I suspect a problem there, but we already knew that.
Yes, its an RMS meter. Yes it's been checked recently.