Manufacturer’s Service Letter Database Project
January 2, 2007
This is a project of the IEEE Power System Relay Committee, Relaying Practices Subcommittee.
From time to time, protective equipment manufacturers issue letters describing problems that have been discovered with their equipment, and solutions to those problems. Engineers recognize that problems do occur, and a manufacturer’s willingness to disseminate such information quickly is a positive thing.
We have assembled a list (database) of these letters that we have received over the past twenty years, and in some cases longer ago than that. Several manufacturers have helped complete the listing. The intention of this work has always been to provide an index to the available letters. There is enough information to decide whether there is a letter available that applies to the situation of interest, and enough information to assist in obtaining a copy of that letter.
Since the database is in dBASE format (a .dbf file), the information can be examined and manipulated with most any of the data base management software products that are available.
Some advisory letters contain information that applies to more than one type of relay. A record has been entered in the database for each type of relay addressed by such letters, and for this reason, the number of records exceeds the number of letters. The size of the database file at this writing is roughly 80k.
It has been suggested that an image of each letter could be captured in a standard electronic form, possibly enlisting the help of the manufacturers. If this is accomplished in the future, then the present database will be ready to serve as an index.
Listed below is a description of the database structure which includes the name of each field, the width, the type of data in that field, and a description the contents.
DESCRIPTION OF FIELDS
EQUIPMENT (18) Character - a short description of the device which is the subject of the letter. Word such as "relay" or "protective" would occur too often to be useful, so they are simply left out. Thus "GENERATOR" refers to a protective relay for generator protection.
TYPE (10) Character - the manufacturers designation for the device which is the subject of the service letter.
MFG (4) Character - manufacturer. the name which is on the original letter, not updated if that name has changed.
DIST (2) Character - distribution. - The letter L appears in this field if it known that the distribution of the letter was limited.
NUMBER (10) Character - assigned to the service letter by manufacturer.
DATE (8) Date - intended to be the date of the original document, not subsequent letters of transmittal. When the original document is dated with only a month and year, the first of that month has been entered as the date. Some letters were not dated by the factory and the date was added when forwarded to customers by field offices. Thus the same letter may be found with various dates.
AFFECTED (14) Character - a brief free-form description of which of the relays are affected by the problem.
PAGES (2) Numeric - number of pages comprising the service advice letter. This may vary, as explained under Date above.
NOTE (22) Character - Most often a very short description of the nature of the problem.
PFILE (3) Numeric - This field is available for each user to insert their own file number
RECORD (4) Numeric - record number. This number is unique to each database record and can be used as a file number. Note however that one service letter can generate more than one record, as explained above.
The names of the file containing the latest version of the Manufacturer's Service Letter Database is serv06c.dbf. This file can be downloaded by clicking on the hyperlink download. Subsequent revisions will be posted on this Web Site when a number of new letters have accumulated. Your comments on the data, or on this written explanation, would be appreciated. If you have an addition or a correction to the data for an individual letter, please send a scanned image of the letter to the database custodian. Please do not make corrections to the database and send in the entire revised database.
Jim Ingleson
New York Independent System Operator
3890 Carman Road
Schenectady, NY 12303
Tel: 518-356-6131
Fax: 518-356-6118
Email: j.w.ingleson@ieee.org
ServiceData.html