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Rockwell Automation Publication 1512A-UM101B-EN-P - December 2021
Chapter 5 Maintenance
Adjusting the Change-of-State Point
This procedure sets the secondary electrical interlock. 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 device to indicate continuity across the closed auxiliary
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.
4. If the auxiliaries do not change state before the isolation switch opens,
repeat the auxiliary contacts adjustment procedure (refer to
Contacts Inspection and Replacement on page 65
).
ATTENTION:
The auxiliary contacts must change state from
the closed to open position before the isolation 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. Failure to correctly set the auxiliary
contacts may result in serious damage to the controller and/
or injury to personnel.
