asymmetrical
40
20
61
25
Page 9
The elastic stop nut at the hinge end must be tightened
to a value of
20 inch-pounds
on all switches.
It is critical that the bolts at both ends of the main blade
assembly be properly tightened. If the bolts are over-
tightened, the switch may not properly open or close. If
the bolts are under-tightened, the blades will not make
a good electrical connection and the switch will
overheat. A resistance reading across each pole can
be used to verify that the blades are tight enough, but
will not indicate if they have been over-tightened. Ohm
readings between the top terminal pad and the bottom
terminal pad on each pole should not exceed 60 micro-
ohms when the bolts are tight.
5.3 Replacement Procedures
WARNING!
Failure to completely disconnect the switch from all
power sources prior to inspection may result in
severe injury or death.
The switch must be completely disconnected from all
power sources before performing inspection.
5.3.1 Main Blade/Hinge Subassembly and Break
Jaw Replacement
Begin with the switch should be in the closed position.
Disconnect the drive rod link from the clevis on the main
shaft. Remove the four bolts holding the hinge
assembly to the lower terminal pad. The hinge, main
blade and flicker blade assembly is now free and may
be removed, along with the lower terminal pad.
Remove the two bolts holding the break jaw to the
upper terminal. Remove the old jaw. Replace the jaw
and finger tighten the two mounting bolts. Replace the
main blade and hinge assembly on top of the lower
terminal pad and finger tighten the four bolts. Align the
blade per paragraph 5.2.3. Tighten the jaw and hinge
mounting bolts. Lubricate per Sec 5.4.
Align flicker blade and arc chute per paragraph 5.2.4.
Check flicker blade function per paragraph 5.1.3. If
satisfactory, re-connect the drive rod link to the main
shaft clevis, being sure to reinstall the clinch spacer in
the large hole in the drive rod. Check the switch for
adjustments per paragraph 5.2.2 and 5.2.5. Perform
the pre-operation check (see Section 3).
5.3.2 Flicker Blade Replacement
Remove the locknut and bolt securing the flicker blade
assembly to the main switch blade. When re-installing,
made certain that the spring is installed against the stop
pin. Verify by pushing the assembly back and
observing its return to the original position.
Flicker
Blade
Fig.11
Flicker Blade Assembly
5.3.2 Springs
The main spring is a large horizontally mounted
compression spring along the inside of the switch frame
on the operating handle side. For higher fault-close
ratings, there is also an auxiliary spring vertically
mounted and connected to the main shaft.
The main and auxiliary springs are not field replaceable.
5.3.3
Pre-Use Check
After completing any maintenance, the alignment
should be checked (See Section 5.2.). After completing
any alignment, the switch should be operated at least
three "close-open" operations to check for proper
performance. Insure that the break jaw has been
properly lubricated per Section 5.4.
5.4 Lubrication
Lubrication is critical to the proper operation of the
switch and should be performed every 100 operations
or yearly, during switch maintenance (see Section 5).
C-H conductive grease, part number 7274A48H02,
should be applied moderately to contact surfaces on
