CR194 Two-High Vacuum Limitamp@ Control
Normal High-Voltage Door
Opening Procedure
To open the high-voltage door to gain access to the
contactor or motor terminals, the contactor must be in
the de-energized position. If the contactor is ener-
gized, the latch release on the isolation switch handle
cannot be pushed in, the handle cannot be operated,
and the door can’t be opened.
Depressing the Stop button de-energizes the
contactor. The latch release on the isolation switch
handle can then be depressed, which opens an electri-
cal interlock (control power interlock, or CPI) in the
secondary of the control power transformer. When the
latch release has been depressed, the isolation switch
handle may be moved to the full “OFF” position by
moving the handle with a rapid, positive motion to the
extreme down position (i.e. the handle latch release
pops back out). When the isolation switch handle is in
the “OFF” (down) position, the high-voltage door may
be opened by turning the two latch bolts.
High-Voltage Door Defeater Latch
WARNING:
The following steps should be taken
only as a last resort to enter a malfunctioning con-
bus be removed before proceeding.
IN CASE OF EMERGENCY, remove all power to the
controller, then the high-voltage door may be opened
with the contactor in the closed position and with the
isolation switch closed, by following the procedure
listed below.
WARNING:
Do not proceed unless all power to the
controller is removed. In this situation, doors must
not be opened with power connected to the bus.
Step 1.
Loosen the two high-voltage door latch bolts as shown
in Figure 46.
Step 2.
Turn the two
l/4
turn latches on the low-voltage door
and open the low-voltage door.
Step 3.
Once the low-voltage door is open, the defeater
mechanism can be located in the lower right corner of
the low-voltage compartment.
Step 4.
Remove the door interlock defeater locking bolt as
shown in Figure 47.
Low “OLT*GE
DOOR LATCHES
Figure 46. view showing door latch ha&vare
Figure 47. Interior view of low-voltage compartment showing
door interlock defeater
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