ML20062G800
| ML20062G800 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 11/01/1990 |
| From: | David Jones GENERAL ELECTRIC CO. |
| To: | Taylor J NRC |
| References | |
| NUDOCS 9012030006 | |
| Download: ML20062G800 (1) | |
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V November 1, 1990 Subjects CE magne-blast Circuit Breakers 4.16 kV Switchgear at Callaway Nuclear Generatin Station Union Electric Co.
Auxiliary Switch Failure Due to Dending of operating Cam During Maintenance
(
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James Taylor, Director h
U. S. Nuclear Regulatory Commission
)
Washington, D.C.
Dear Mr. Taylor We received a report of the failure of 4.16kV vertical-lift switchgear, cell mounted, auxiliary contacts to operate on command during the testing of auxiliary stand-by switchgear at Callaway Nuclear Generating Station by Mr. T.
Hooper of Union Electric Co.
The failure has been analyzed by the customer, and we concur, that when an improperly adjusted test link is inserted between the breaker (in the withdrawn position) and the stationary auxiliary switch, the design is such that excessive force may be applied to the actuating cam on the breaker operating. shaft, causing the cam to be deformed. When the breaker is then inserted in-the-cubicle (in the connected position), there is insufficient vertical cam travel to operate the cell mounted auxiliary switch.
We are presently shipping modified commercial grade material to Union Electric to correct this situationt we will be developing documentation for safety
.related use where we supply such parts and will inform you and our customers of our progress and recommendations.
This condition can only exist where users have optional cell mounted auxiliary switches, the optional maintenance test link, and where the link has been adjusted to apply excessive operating force.
Very truly yours$
I f
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g [, 'l e 4 Dean Jones product Manager, Breakers l
cc: Carl erlinger, Chief - Generic Communications Branch, NRC via fax: (301) 492-0260 M.C. Neal, GE, King of Prussia via fax: (215) 964-7673 G.
Strambach, GE NEBO, San Jose via fax: (408) 925-4458 9012030006 901101 PDR ADOCK 05000493
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