Citadel 2.0 - Instruction Manual - page:
126
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M A I N T E N A N C E
Contact Erosion Continued
Draw out breakers often have run-backs and finger clusters that impede direct visualization
of the VI contact erosion dot. In such cases a simple alternative test can be performed with
a “Citadel erosion wear tool” .
Properly trained O&M personnel can use this simple go / no go gauge type device and
“attempt” to insert it in the gap between the Main Armature Shaft and the sliding bar
assembly at the bolted connection point between the breaker VI push rod assembly (page
25 - drawing 3, item #11) and the Breaker Main Armature Shaft (page 40 - figure#14, item #
11).
The gap should be such that the tool will NOT insert into the gap. Upon erosion of the VI
contacts by 3mm or greater – the enlarged gap will allow insertion of the tool and thereby
demonstrate that end of life wear has been reached for the VI.
In these QR code video scenarios (one per phase) we have assume a FAILED interrupter
and therefore the gauge tool allows for insertion into the gap.
The tool should normally NOT fit into the gap if the VI is OK.
The Citadel VI wear tool gauge should be 26.5 mm and if the VI IS GOOD the tool should
NOT fit in the opening when the breaker is closed.
This INABILITY to insert the tool into the gap shows that the VI has LIFE left to it from the
point of view of wear.
As the VI contacts wear down – that gap between the top of the switching bar ( the top of
the push rod ) and the Main Shaft will grow.
As that gap grows – when you get to 26.5 mm or a little larger and the tool then fits into the
gap – at that time the VI is worn down beyond that allowable 3mm and should be replaced.
FIGURE 111-C
FIGURE 111-B
