46
shows two typical wicket gate plan outlines. On wicket
gate A, the distance from the heel contact point to gate shaft is longer than the distance from the toe contact
point to the gate shaft. On wicket gate B, the opposite is true. Because of these differences, any movement
initiated at the heel will be proportionally more or less at the toe. In the case of gate A, the movement at
the toe would 13/16 of the movement at the heel. In a similar fashion, any movement initiated at the toe
contact point will be amplified at the heel. When adjusting wicket gates with a geometry similar to gate A,
it is important to initiate the adjustment at the heel of the gate and proceed in the gate adjustment opposite
in direction of the runner rotation. The adjustment of wicket gates similar to Gate B should start with the
toe, and continue in the same direction as runner rotation. In this way, the amount each gate is affected by
the adjustment of the first gate is gradually reduced. For example, if the heel of gate A was moved 0.010
inch and the gates were adjusted going opposite the direction of runner rotation, the movement of the toe of
twentieth or last gate would be appro3dmately 0.0002 inch. If the adjustment proceeded in the direction on
runner rotation, a 0.010-inch movement at the toe of the master gate would cause the heel of the final gate
to move 0.630 inch. When studying the drawings to determine which gate type a particular unit has, it is
important to use the distance to the contact points and not the total length of the gate.
point to the gate shaft. On wicket gate B, the opposite is true. Because of these differences, any movement
initiated at the heel will be proportionally more or less at the toe. In the case of gate A, the movement at
the toe would 13/16 of the movement at the heel. In a similar fashion, any movement initiated at the toe
contact point will be amplified at the heel. When adjusting wicket gates with a geometry similar to gate A,
it is important to initiate the adjustment at the heel of the gate and proceed in the gate adjustment opposite
in direction of the runner rotation. The adjustment of wicket gates similar to Gate B should start with the
toe, and continue in the same direction as runner rotation. In this way, the amount each gate is affected by
the adjustment of the first gate is gradually reduced. For example, if the heel of gate A was moved 0.010
inch and the gates were adjusted going opposite the direction of runner rotation, the movement of the toe of
twentieth or last gate would be appro3dmately 0.0002 inch. If the adjustment proceeded in the direction on
runner rotation, a 0.010-inch movement at the toe of the master gate would cause the heel of the final gate
to move 0.630 inch. When studying the drawings to determine which gate type a particular unit has, it is
important to use the distance to the contact points and not the total length of the gate.
Wicket Gate A
(Distance from heel contact point to gate shaft centerline is longer than the distance from the toe 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, zero gate (squeeze) position.
2. Bleed the air from the governor accumulator tank to provide zero pressure on the servomotors.
3. Disconnect aR wicket gate linkage.so that gates are free to move independently.
4. Select a "master" wicket gate. Open gate slightly (less than 0.020 inch).
5. Moving in the direction opposite 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 heel contacts the toe of the master gate. Take care not to move the
master gate.
adjacent to the master gate until the heel contacts the toe of the master gate. Take care not to move the
master gate.
6. Continue adjusting each gate in sequence in the direction opposite of runner rotation, adjusting the
heel of the gate to contact the toe 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.
gate 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 heel of the master gat
e
and the toe of the last gate (20) or between the heel
of the last gate (20) and the toe of the next