Emerson 7ATB Power Supply User Manual


 
BYPASSING & ISOLATING
(continued)
3 --- 4
RETURN TO SERVICE
This procedure explains how to return the automatic
transfer switch (ATS) to service after inspection and
maintenance. Observe the Bypass Switch Position
indicator and lights). Refer to Figures 3–7a, 3–7b, 3–8,
3–9, and 3–10.
1. Slide the transfer switch (ATS) into the enclosure
(isolation contacts facing inward) until its crank pins
engage the latch plates on both sides. On 4000 A
sub s tan tial forc e is require d to overc o m e deten ts on
the rails. Next push in side rail carriage. On 4000 A
first retract the two legs and lock them in place. See
Figure 3–7b. Then close enclosure door.
Close the enclosure door to prevent personal
injury in case of electrical system fault.
Align position indicator. Do not leave
thehandleinanintermediateposition.
unfold
crank
position
window
clockwise draws in the Transfer Switch
CONN
TEST
ISOLATE
Figure 3–8. Isolation Handle.
2. Turn the Isolation Handle clockwi se (approx. 7
turns, approx. 8 turns for 4000 A) until the window
shows TEST. The ATS can be tested now wi thout
load inte rruption (see page 2–1).
E
L
N
Turn crank
clockwise
until
window
shows
TEST.
ATS
Bypass Switch
Figure 3–9. ISOLATE to TEST position.
Solenoid interlock prevents you from closing
the isolation contacts until the ATS is in the
same
position as the Bypass Switch.
3. Observe which Bypass Switch Position indicator is
black (NORMAL or EMERGENCY)attheBypass
Switch Handle. This indicates the source
connected to the load.
4. Observe which Transfer Switch Connected To light is
on (Normal or Emergency) on the door. This is the
position of the Transfer Switch. If it is not in the
same position as the Bypass Handle change the
position of the Transfer Switch as follows:
To change the position of transfer switch
Operate to NORMAL OperatetoEMERGENCY
Turn Transfer Control
switch to Retransfer
Delay Bypass.
Turn Transfer Control
switch to Transfer Test
(hold 15 seconds).*
Connected To Normal
light should come on.
Connected To Emergency
light should comes on.
* If Feature 2B time delay is used, there will be a delay
before transfer to Emergency.
NOTE: With Normal available, the
automatic transfer switch will not stay in the
emergency position unless Feature 3A time
delay is used (at least 30 seconds).
Do not close the isolation contacts unless
the Transfer Switch (ATS) and Bypass
Switch a re in the same positio n!
5. When the transfer switch is in the same
position as
the Bypass Switch handle, continue turning the
Isolation Handle clockwise (approx. 16 turns,
approx. 12 t urns for 4000 A) until the window
shows CONN (connected).
E
L
N
Turn crank
clockwise
until window
shows
CONN
(connected).
ATS
Bypass Switch
Figure 3–10. TEST to CONNECTED position.
Now continue to the next page for instructions o n how to
return the Bypass Handle to the OPEN postition.