21
I.B. 8926-1A
DETENT POSITION
For maintenance and test purposes, the unit can be
partially withdrawn (approximately 1 ½ inches) until
the stabs are free of the bus. In this position, the
quarter-turn latch can be rotated clockwise to
engage the detent position slot; this will secure the
unit to ensure the stabs remain disengaged during
maintenance. See Figure 29. The latch can be
padlocked in this position.
OPERATING HANDLE LINKAGE
ADJUSTMENT
Movement of the operating handle in the vertical
plane should not be restricted by the handle cavity at
either the top or bottom to its travel. Should
restriction occur, eliminate it adjusting the length of
the operating linkage as shown in Figure 30.
Depending on the type of primary disconnect device
contained in the control unit, it may be necessary to
lengthen or shorten the linkage.
AUTOMATIC SHUTTER TRAVEL
ADJUSTMENT
When the optional labyrinth vertical bus barrier is
installed in the control center, a shutter is provided
to automatically cover the stab openings when a
control unit is withdrawn. The shutter is opened by
engagement of the left-hand side of the control unit
with the shutter arm linkage attached to the left-hand
vertical structural members. When the unit is
withdrawn free of the linkage, a spring automatically
moves the shutter to its closed position. See Figure
31 and Figure 4.
With the control unit removed, the shutter should
completely cover the stab openings. If it does not
cover the openings, use an adjustable wrench to
bend the link arm to the right until the shutter covers
the stab openings.
If, on re-insertion of the control unit, interference is
felt between the stab assembly at the rear of the unit
and the shutter, the engagement of the control unit
with the shutter arm linkage is insufficient to fully
open the shutter. Use an adjustable wrench to bend
the linkage arm inward toward the unit to increase its
engagement with the unit. An inward bend of
approximately ¼ inch will provide sufficient
additional shutter travel.
INSTALLING PILOT DEVICES
The device panel can accommodate up to six pilot
devices such as oil-tight pushbuttons, indicating
lights, selector switches and miniature meters. If
unused space is available and the addition of other
devices is desired, observe the following procedure.
After opening the unit door, loosen the two screws at
the top of the device panel. Slide the panel ½ inch
left to permit it to swing down for access. See Figure
32. With the peen end of a ball-peen hammer or with
a drift or chisel, remove the desired knockout.
Fig. 29 Unit Locked in Detent Position
Fig. 30 Operating Handle Linkage Adjustment
Fig. 31 Shutter Arm Linkage
