Page 433 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Steam Turbines and Turboexpanders 411

3. Check the linkage jam nuts, set screws and shoulder screws to en-
sure that they are tight.
4. Turn the speed adjusting screw to minimum speed (counterclock-
wise).
5. Start the turbine in accordance with the initial startup procedures,
given earlier, and check the governor for oil leakage, vibration and
ease of linkage operation.
6. After the turbine is thoroughly warmed up and operating satisfacto-
rily at minimum speed; slowly increase speed, by turning the speed
adjusting screw clockwise, until the turbine is operating at rated
Speed.
7. Continue to monitor the overall governor operation for any abnor-
mal conditions.

Note: Due to the design characteristics of the TG-10 governor the
operating temperature may often exceed 200°F (94°C).
Continuous operation at this temperature is acceptable and
does not exceed the design limits. The governor may feel un-
usually hot to the touch, but this is not an indication of over-
heating.

8. After the turbine has been operated satisfactorily at rated speed (for
approximately one hour), check the overspeed trip by turning the
speed adjusting screw full travel in the clockwise direction while
closely monitoring the turbine speed. If the rated trip speed cannot
be obtained by turning the adjusting screw, it will be necessary to
overcome the governor, by placing a bar between the governor
valve lever and the valve cover and slowly prying the governor
valve open.

Caution: Pry the valve evenly and squarely from the valve body.
Uneven force on the valve stem can bend the stem and
cause binding. Also, monitor the turbine speed closely. If
the turbine does not trip within 2 percent of the rated trip
speed, strike the hand trip lever and adjust the overspeed
trip as discussed earlier.

Routine Start-up
Start the turbine as outlined in Routine Startup procedures, earlier.
Monitor turbine speed and turn the speed adjusting screw as required to
bring the turbine to the desired speed.