Siemens Services Technical Bulletin SSTB 13-002
Product: YMV Voltage transformer fuse assembly
Production year affected: Manufactured up to 1989
Modification Required: Replacement of voltage transformer fuse contact pin
Priority of Change: Next planned maintenance
This product bulletin affects the Reyrolle 11kV, YMV; 1250A voltage transformer fuse assembly manufactured up to 1989 and has been subjected to ENA DIN 2007/0072/00.
In 1989 a modification was introduced to the voltage transformer contact pin (part number 1323A1408) to add a collar to guarantee that the contact spring applies adequate contact pressure to fuse assembly.
Prior to this modification a number of failures had occurred due to the contact spring ‘riding’ over the shoulder of the contact pin and hence reducing the contact pressure onto the voltage transformer fuse assembly.
It has come to our attention that some of the voltage transformer fuse assemblies have not been modified.
Although the risk of failure of un-modified units is classified as low, it is strongly recommended that during planned maintenance that the voltage transformer fuse contact spring pin (part number 1323A1200) are replaced with the modified version (part number 1323A1408).
The panel is to be removed from service and the voltage transformer fuse assembly withdrawn from the panel. Remove the fuse contact assembly and remove the split pin that secures to contact pin to the contact block. Discard the old fuse contact pin (part number 1323AA1200). Reassembly using new split pin and the new contact pin (part number 1323A1408).
New voltage transformer fuse contact pins can be obtained from Siemens Services Tendering Department.
Photographs showing voltage contact pin before and after modifications. List of serial number of those panels involved.
13/09/2013 | Author: Name