Emerson 7ADTB Contact Inspection, BYPASSING & ISOLATING continued, Remove the barrier Figure

BYPASSING & ISOLATING (continued)

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.

tab

handles

left rail right rail

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.

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.

To prevent the possibility of fatal electrical shocks and burns, bypass, isolate, and withdraw the transfer switch before working on it.

Figure 3–14. Barrier removal.

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