User`s guide

BYPASSING & ISOLATING
(continued)
InstallationManual ASCOG,Q,S,U7ATB,7ACTB,7ADTB
p a g e 3 --- 2
ASCO Power Technologies 381333–415 A
ISOLATING THE AT S
Isolating is required before any service work can be
performed on the automatic transfer switch (ATS). Refer
to Figures 3–4, 3–5, 3–6, 3–7a, and 3–7b.
1. Bypass the closed
automatic transfer switch contacts.
See BYPASSING on page 3–1.
NOTICE
Align the position indicator. Do not leave
thehandleinanintermediateposition.
2. Turn the Isol ation Handle cou nter c l oc kw ise (appr ox. 16
turns, approx. 12 turns for 4000A) until window shows
TEST. The ATS can be tested now without load
interruption (see page 2–1).
E
L
N
Automatic Transfer Switch
Bypass Switch
Turn crank
counter-
clockwise
until
window
shows
TEST.
Figure 3–4.
CONNECTED to
TEST position.
3. Con tinu e turning the Isol ation Handle cou n ter cl o c k-
wise (approx. 7 turns, approx. 8 turns for 4000 A) until
the wind ow shows ISOLA TE.
E
L
N
Turn crank
counter-
clockwise
until
window
shows
ISOLATE.
Automatic Transfer Switch
Bypass Switch
Figure 3–5.
TEST to
ISOLATE
position.
4. Open the lower enclosure doors(s). Pull out the side
rail carriage. On 4000 A extend two support legs. See
Figures 3–7a and 3–7b. Then roll out the transfer
switch. It can be safely inspected in this position.
The transfer switch can also be removed for easier
maintenance operations.
unfold
crank
position
window
CONN
TEST
ISOLATE
counterclockwise – draws out transfer sw itch
Figure 3–6. Isolation Handle.
NOTICE
In the TEST position the transfer switch solenoid
operator circuit is energized through secondary
disconnect contacts.
Hazardous voltage capable of causing electrical
shock, burns, or death; do not touch any control
circuit terminals.
Figure 3–7a. 600–3000 A transfer switch
isolated and pulled out for inspection.
See page 2–1 for maintenance handle use. Lifting yokes
are available to facilitate lifting transfer switch by using
an overhead crane or similar equipment.
600–3000 A transfer switches weigh 350---450 lbs;
use lifting yoke kit 607064 or other device capable
of lifting this weight to avoid personal injury or
equipment damage.
Continued on next page