3 |
P a g e
Step 3 —Mounting Operating Bearing
Mount the operating bearing and its supporting
base on the supporting structure as shown on the
control drawing. Check the operating crank for the
proper radius and angle. Also, make sure the stop
crank is mounted correctly and that the stops are
positioned correctly.
If the operating bearing has an adjustable crank, it
is sometimes necessary to add 1/4" to 1/2” to the
trial radius given on the control drawing to get
required travel to switch blades. This additional
length allows for lost motion and clearances in pin
holes and will also provide a definite audible
sound accompanied by a reasonable amount of
deflection in the structural members when the
crank crosses the dead canter position. This serves
as a signal to the operator that the switch is either
fully open or closed.
Step 4 -–Mounting Insulators
Using the bolts provided, assemble the insulators
to their supports on switch bases. Make sure that
operating cranks under the rotating column are
positioned properly (refer to the control and
single-pole switch drawings). If necessary to
adjust the insulator columns for variation in
heights or proper angle, use the shims, leveling
bolts or leveling screws as provided, see Fig. 1.
Step 5 —
Mounting Current Carrying Parts
Rotate the center insulator column to the open
position as shown on the drawings. The stop at the
bottom of the column limits the travel. At this time,
the crank at the bottom of the insulator column will
be at an angle of 60° to the switch base. (On 345
and 500 kV switches, first mount corona rings on
top of insulators and under the current carrying
parts).
Mount the blade assembly on the center insulator
column at an angle of 70 degrees to the centerline
of the switch base which is 10 degrees further in a
clockwise direction than the switch crank, see Fig.
3. Mount the switch jaw assembly on the end
insulators leaving the mounting bolts finger tight in
order to allow for any adjustments later for proper
alignment.
Step 6 —Switch Adjustment (One Pole at a Time)
On an upright mounted switch, the direction of
rotation of the center insulator column (looking at
the switch form above) is clockwise to open and
counter clockwise to close.
6—1 Blade Entry
Using a piece of pipe over the crank at the bottom
of the rotating insulator stack, move the switch
blade slowly toward the closed position. The
Summary of Contents for TTT7
Page 1: ...IB TTT7 May 2012 ...
Page 7: ...6 P a g e ...
