Emerson 7ADTB manual BYPASSING & ISOLATING continued, Return To Service, Middle amber light, Test

BYPASSING & ISOLATING (continued)

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 indica- tor and lights).

1.Use the two tab handles to roll the transfer switch into the enclosure (isolation contacts facing inward) until the crank bearings stop against the draw–in plates. Then push in both side rails and close the enclosure door.

tab

handles

left rail right rail

Figure 3–15.Transfer switch isolated

and pulled out for inspection.

Close the enclosure door to prevent personal

injury in case of electrical system fault.

2.Turn Isolation Handle clockwise (approx. 6 turns) until the window shows TEST and TS TEST light comes on.

Bypass Switch	E
Turn crank
clockwise
until	L
window
shows
TEST.
	N
Automatic Transfer Switch
Figure 3–16. ISOLATE to TEST position.

3---5

TS CONNECTED

Middle amber light
should come on.	TS TEST
	TS ISOLATED

position	TEST	clockwise – draws in
window		the transfer switch

Figure 3–17. Isolation Handle turned to TEST.

3.The ATS can be tested now without load interruption (see page 2–1).

Solenoid interlock prevents you from closing the isolation contacts until the ATS is in the same position as the Bypass Switch.

4.Observe which Bypass Switch Position window indica- tor is yellow (NORMAL or EMERGENCY) at the Bypass Switch Handle. This indicates the source connected to the load.

5.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	Operate to EMERGENCY
Turn Transfer Control	Turn Transfer Control
switch to Retransfer	switch to Transfer Test
Delay Bypass.	(hold 15 seconds).*
Connected To Normal	Connected To Emergency
light should come on.	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).