Bypassing & Isolating Installation Manual
381333-415 B 11
ISOLATING THE ATS
Isolating is required before any service work can be
performed on the automatic transfer switch (ATS).
Refer to Figures 11,12, 13, 14 and 15..
1. Bypass the closed automatic transfer switch
contacts. See BYPASSING on page 10.
Align the position indicator. Do not leave
the handle in an intermediate position.
2. Turn the Isolation Handle counterclockwise
(approx. 16 turns, approx. 12 turns for 4000A)
until window shows TEST. The ATS can be
tested now without load interruption (see page 8).
3. Continue turning the Isolation Handle
counterclockwise (approx. 7 turns, approx. 8 turns
for 4000 A) until the window shows ISOLATE.
4. Open the lower enclosure doors(s). Pull out the
side rail carriage. On 4000 A extend two support
legs. See Figures 14 and 15. 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.
Figure 13. Isolation Handle.
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 14. 600–3000 A transfer switch
isolated and pulled out for inspection.
See page 8 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
E
L
N
Automatic Transfer Switch
Bypass Switch
Turn crank
counter
clockwise
until
window
shows
TEST.
Figure 3
–
4.
CONNECTED to
TEST position.
E
L
N
Turn crank
counter
clockwise
until
window
shows
ISOLATE.
Automatic Transfer Switch
Bypass Switch
Figure 3
–
5.
TEST to
ISOLATE
position.
unfold
crank
position
window
CONN
TEST
ISOLATE
counterclockwise
–
draws out transfer switch
Figure 11.
CONNECTED to
TEST position.
Figure 12
TEST to
ISOLATE
position.
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