Page 3
Leveling Screws
Shims Used for Leveling Switches
Shims (As Reqired)
Base Channel Flange
Rotor or Spacer Base
Leveling Screw
Rotor or Spacer Base
Base Channel Flange
Fig. 1 Types of Leveling Devices
Leveling Bolts
Rotor or Spacer Base
Base Channel Flange
Adjusting Nuts
Taper Washer
(When Used)
Taper Washer
(When Used)
Taper Washer
(When Used)
Fig. 2 Proper Rigging for Vertical Break
Step 3—Insulator Stack Alignment
Lower voltage switches 8.25 thru 72.5kV
generally do not require insulator stack alignment.
Where required, the insulator stacks of switches
thru 242kV can be aligned using open-end shims
or leveling screws and/or adjusting nuts (Fig. 1) if
supplied (optional).
•
If using shims, place the shims under the
insulator supports (rotor bearing or spacer
mounting flange) where the bolts secure the
rotor bearing or spacer mounting flange to the
switch bases.
•
If optional leveling screws and/or adjusting
nuts have been supplied, as shown in Fig. 1,
adjust the leveling screw and/or adjusting nut
to align the insulator stacks. Loosen all
hardware before jacking to prevent binding.
Step 4—Mount Current Carrying Parts
Make certain that the base crank is in the proper
position when mounting current carrying parts, i.e.
base crank rotated to the maximum clockwise
position with the blade open. When assembling
the jaws on the insulator columns, leave the
mounting bolts finger tight. This will permit the
jaw base to be rotated and shifted slightly for
subsequent contact alignment. This alignment will
be discussed later under blade entry (step 6).
Note: The counterbalances are assembled at the
factory for the mounting positions as required for
each installation. If it is necessary to change the
mounting position of the switch in the field, the
counterbalance must be changed as well. See
Appendix A on page 12.
Step 5—Mount Switches
Assemble the switches on the supporting structure
in accordance with the positions shown on the
installation drawing. The switches should be
mounted level and parallel with each other. In case
of a warped structure, shimming under the switch
bases may be required. See Fig. 2 for proper
rigging.
Step 6—Switch Blade Adjustment
When looking down on the single pole’s rotating
insulator stack, rotate the stack clockwise to open
and counter-clockwise to close the switch. First,
make sure that stop bolts at base of rotating
insulators do not prevent switch from traveling to
the complete open and closed positions, then check
each pole unit for the following items:
Blade Entry
—Lower the blades slowly to the
closed position to see if blade contact enters the jaw
in a central position. If it does not, loosen the hinge
assembly mounting bolts on stationary insulator
stack and with blade just out of the jaw, shift blade
into alignment and tighten hinge assembly
mounting bolts. Should this fail to give proper
blade entry, the jaw insulator stack should be
shimmed or adjusted to suit. When central entry is
achieved, rotate the blade into contact and tighten
jaw base mounting bolts. Also make certain the jaw
fingers are nearly centered on the blade end contact.
