Woodward 505XT, Installation And Operation Manual, Page: 131 / 242

Manual 35018V1 505XT Digital Control System for Steam Turbines
Woodward 129
CRITICAL SPEED 2 MAX (rpm) dflt= 1.0 (1.0, 20000)
Set the upper limit of the critical speed avoidance band.
(Must be less than the ‘Minimum Governor Speed’ Setting)
CRITICAL SPEED 2 MIN (rpm) dflt= 1.0 (1.0, 20000)
Set the lower limit of the critical speed avoidance band.
(Must be less than the ‘Critical Speed 2 Max’ Setting)
USE CRITICAL SPEED 3 ? dflt= NO (Yes/No)
Select YES to use the second critical speed avoidance band.
CRITICAL SPEED 3 MAX (rpm) dflt= 1.0 (1.0, 20000)
Set the upper limit of the critical speed avoidance band.
(Must be less than the ‘Minimum Governor Speed’ Setting)
CRITICAL SPEED 3 MIN (rpm) dflt= 1.0 (1.0, 20000)
Set the lower limit of the critical speed avoidance band.
(Must be less than the ‘Critical Speed 3 Max’ Setting)
Speed Control Menu
(The maximum speed input frequency is 35000 hertz.)
PROBE TYPE dflt= MPU (MPU, ACTIVE)
Set the probe type, whether passive or active,.
NUMBER OF GEAR TEETH SEEN BY MPU dflt= 60.0 (1, 300)
Enter the number of teeth on gear that the speed probe is mounted on.
MPU GEAR RATIO dflt= 1.0 (0.05, 100)
Enter the speed sensor gear ratio. This value is the ratio of the speed sensor gear to the turbine
shaft. This gear ratio is the result of dividing the speed of the speed sensor gear by the speed of the
turbine shaft.
MAXIMUM SPEED LEVEL (rpm) dflt= 250 (0.5, 1000)
Enter the Maximum Speed Level (in rpm) to set the speed probe input maximum detectable level. If
speed goes above this level, it will not be read in the control.
(Must be greater than the Overspeed Test Limit Setting)
A suggested value is shown
FAILED SPEED LEVEL (rpm) dflt= 250 (0.5, 1000)
Enter the Failed Speed Level (in rpm) to set the speed probe input failure level. If speed drops below
this level, the control will determine the speed input device is failed and issue an alarm. If all speed
inputs fail, the 505 will issue a trip on loss of speed inputs.
(Must be greater than or equal to 0.0204 x Maximum Speed Level)
Note: The MPU override level is this value + 50 RPM. When speed increases above this level the
speed input override is removed and the failure detection is armed. A suggested value is shown
USE SPEED INPUT #2? dflt= NO (Yes/No)
Select YES if both speed inputs are to be used.
PROBE TYPE dflt= MPU (MPU, ACTIVE)
Set the probe type, whether passive or active,.
NUMBER OF GEAR TEETH SEEN BY MPU dflt= 60.0 (1, 300)
Enter the number of teeth on gear that the speed probe is mounted on.
MPU GEAR RATIO dflt= 1.0 (0.05, 100)
Enter the speed sensor gear ratio. This value is the ratio of the speed sensor gear to the turbine
shaft. This gear ratio is the result of dividing the speed of the speed sensor gear by the speed of the
turbine shaft.
MAXIMUM SPEED LEVEL (rpm) dflt= 250 (0.5, 1000)
Enter the Maximum Speed Level (in rpm) to set the speed probe input maximum detectable level. If
speed goes above this level, it will not be read in the control.
(Must be greater than the Overspeed Test Limit Setting)
A suggested value is shown
FAILED SPEED LEVEL (rpm) dflt= 250 (0.5, 1000)
Enter the Failed Speed Level (in rpm) to set the speed probe input failure level. If speed drops below
this level, the control will determine the speed input device is failed and issue an alarm. If all speed
inputs fail, the 505 will issue a trip on loss of speed inputs.
(Must be greater than or equal to 0.0204 x Maximum Speed Level)
Note: The MPU override level is this value + 50 RPM. When speed increases above this level the
speed input override is removed and the failure detection is armed. A suggested value is shown