49
Wicket Gate B
(Distance from toe contact point to gate shaft centerline is longer than the distance from the heel contact
point to the gate shaft centerline.
point to the gate shaft centerline.
1. All adjustments are made with the unit unwatered. Move the servomotor and gate operating linkage
to the full pressure closed (squeeze) position.
to the full pressure closed (squeeze) position.
2. Bleed the air from the govemor accumulator tank to provide zero pressure on the servomotors. The
servomotor indicator should indicate zero gate position.
servomotor indicator should indicate zero gate position.
3. Disconnect all wicket gate linkage so that gates are free to move independently.
4. Select a "master" wicket gate. Open gate shghtly (less than 0.020 inch).
5. Moving in the direction of runner rotation go two gates down from the master gate and open this
gate slightly. This allows the gate adjacent to the master gate to be moved. Adjust the gate adjacent to the
master gate until the toe contacts the heel of the master gate. Take care not to move the master gate.
master gate until the toe contacts the heel of the master gate. Take care not to move the master gate.
6. Continue adjusting each gate in sequence in the direction of runner rotation, adjusting the toe of the
gate to contact the heel of the previous one. It will be necessary in most cases to slightly open the gate
ahead of the one to be adjusted to allow it to move.
ahead of the one to be adjusted to allow it to move.
7. After making a complete rotation of the gates, there should be no clearances between gates except
between the toe of the master gate
(gate 1 - figure D4) and the heel of the last gate (20) or between the toe
of the last gate (20) and the heel of the next to last gate (19). Slightly open the gate ahead of the clearance
(gate 2 if the clearance is between 1 and 20, or gate 1 if the clearance is between 19 and 20) and move the
toe of gate at the clearance to contact the heel of the adjacent gate. Repeat step 6 until all clearances are
acceptable.
of the last gate (20) and the heel of the next to last gate (19). Slightly open the gate ahead of the clearance
(gate 2 if the clearance is between 1 and 20, or gate 1 if the clearance is between 19 and 20) and move the
toe of gate at the clearance to contact the heel of the adjacent gate. Repeat step 6 until all clearances are
acceptable.
8. Verify that the servomotor is still in the zero gate position and move if necessary. Loop a
wire rope sling around the gates and draw tight with a ratcheting hoist to hold gates while wicket
gate linkage is attached. Extreme caution must be used to prevent overloading the sling or
the hoist. The sling used must have a rating higher than the hoist, and the hoist must have
some type of overload indication. Attach wicket gate linkage and adjust to hold gates in
position. After all of the linkage has been connected, remove the sling, repressurize the system,
move the gates through their full travel several times, and check clearances.
gate linkage is attached. Extreme caution must be used to prevent overloading the sling or
the hoist. The sling used must have a rating higher than the hoist, and the hoist must have
some type of overload indication. Attach wicket gate linkage and adjust to hold gates in
position. After all of the linkage has been connected, remove the sling, repressurize the system,
move the gates through their full travel several times, and check clearances.