Rockwell Automation 1512A MV Controllers - 800A One-High Cabinet User Manual

Page 68

5-20

Maintenance

1512A-UM102B-EN-P – June 2013

Adjusting the Normally Closed (ISb) Contacts

1) Move the isolation switch handle to the OFF (open) position.

2) Loosen the bolt holding the inside cam to the shaft. Do not loosen the

bolt entirely. The cam should not be able to rotate freely on the shaft.

3) Insert a 0.25 in. (6.35 mm) diameter pin into the cam groove

between the cam follower and the end of the cam groove.

4) Adjust the cam on the shaft so that the gap from the cam follower to

the end of the cam groove is the width of the pin — 0.25 in. (6.35 mm).

5) Tighten the bolt that holds the cam to the shaft. Move the isolation

switch handle to the OFF position and recheck the gap using the pin.

6) Operate the handle several times, then recheck the 0.25 in. (6.35

mm) clearance between the end of the cam groove and the follower

pin for both cams.

7) Verify that auxiliary contact ISb is closed when isolation switch

is open. Verify that ISb contact is open when isolation switch is

closed.

Adjusting the Change-of-State Point

This procedure sets the secondary electrical inter-

lock. When properly adjusted, the electrical interlock

is designed to open the control power circuit before

the isolation switch opens as the handle is moved to

the OFF position.

1) Once the auxiliaries have been adjusted, move the isolation switch

handle to the ON position.

2) Connect a conductivity measuring device across the closed auxil-

iary contacts.

3) Slowly move the isolation switch handle towards the OFF position

and observe the point at which the movable isolation switch blades

separate from the incoming line stabs. The auxiliary contacts must

change state from the closed to open position before the isola-

tion switch blades lose contact with the incoming line stabs. This

prevents the isolation switch from being opened while the unit is

energized and under load conditions.

The auxiliary contacts must be properly adjusted

to avoid opening the isolation switch under load

conditions. Improper adjustment may result in

damage to the equipment and/or severe burns, injury

or death to personnel.

4) If the auxiliaries do not change state before the isolation switch

opens, repeat the auxiliary contacts adjustment procedure (see page

5-18).

Emergency

Circumventive Procedure

for Power Cell Entry (cont.)

Isolation Switch Auxiliary Con-

tacts (cont.)

I M P O R T A N T

A T T E N T I O N