Emerson 7ADTB - Manual (Page 13)

BYPASSING & ISOLATING
(continued)
3---4
4. Open the lower enclosure door. Pull out both left and
right side rails then use the two tab handles to roll out
the transfer switch. It can be safely inspected in this
position. The transfer switch can also be removed for
easier maintenance operations. See Figure 3–13.
Hazardous voltage capable of causing
electrical shock, burns, or death;
do not touch any control circuit terminals.
right rail
left rail
tab
handles
Figure 3–13.Transfer switch isolated
and pulled out for inspection.
See page 2–2 for maintenance handle use. A lifting yoke
812053 is available to facilitate lifting by using an
overhead crane or similar equipment. See WARNING.
The Transfer Switch weighs about 150 lbs.
depending upon the number of poles. Use lifting
device 812053 or other device capable of lifting
this weight to avoid personal injury or equipment
damage. Two persons are recommended.
Contact Inspection
Contact condition should be checked annually.
Discoloration is normal. Do not file contacts
because it wastes material. Instead use light emery
paper to clean up the contact surfaces. The
non–replaceable main contacts are designed to last
the life of the transfer switch.
To prevent the possibility of fatal electrical
shocks and burns, bypass, isolate, and withdraw
the transfer switch before working on it.
1. Deenergize transfer switch (pages 3–1 thru 3–4)
Bypass, isolate, and withdraw transfer switch.
Use a voltmeter to verify that no electrical
power is present at the transfer switch terminals.
2. Use the maintenance handle (page 2–2).
Open the contacts that will be inspected by using
the detachable maintenance handle.
3. Remove the barrier (Figure 3–14).
Use a phillip screwdriver to loosen (ccw) four or
six captive round–head screws holding the
barrier to the arc chutes. Then pull the barrier
straight outward to remove it.
4. Reinstall the barrier.
Install the barrier over the arc chutes. Use a
phillips screwdriver to tighten (cw) the four or six
round–head screws to secure the barrier to the arc
chute insulator nuts. See Figure 3–14.
Figure 3–14. Barrier removal.