United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9703200381



Limitorque

Corporation

                            February 26, 1997





SUBJECT:       COUNTERFEIT SMB-1 WORM SHAFT GEAR



BACKGROUND



General Public Utilities experienced a clutching problem which was traced

to a loose clutch lug pin in the Worm Shaft gear.  The component was

returned to Limitorque for comment.



LIMITORQUE EVALUATION REVEALED:



     1.   Worm Shaft gear counter bore staking operation to secure motor

          clutch gear cam pin was omitted..  Serious violation.

     2.   Worm Shaft gear lugs were not heat treated.  Serious violation.

     3.   Gear teeth were not shaved.  Profile had significant error.

          Serious violation.

     4.   Variety of other non serious geometric violations.



ENGINEERING CONCLUSIONS



     1.   Worm Shaft gear assembly was not manufactured by Limitorque

          Corporation.

     2.   Worm Shaft gear assembly was inferior in design and manufacture

          referenced to the same Limitorque components and was not

          suitable for the intended application.  The counterfeit

          component would have experienced a short service life

          terminating in failure with associated consequences depending

          upon the criticality of the application.





Ivan E. Wilkinson, P.E., Ph.D

Director of Engineering



Limitorque Corporation  P.O. Box 11318   5114 Woodall Road

Lynchburg, VA 24506-1318   Tel. (804) 528-4400   FAX (804) 845-9736





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