OCB Breaker Manufacture Manauls.pdf

This document is the Installation and Maintenance Instructions (Service Information S290-40-3) for McGraw-Edison Power Circuit Breakers, Types AHF-48 and AHF-54, applicable to units manufactured after July 1, 1980, under Orders C-03354-4 and C-03546-4. The instructions provide comprehensive guidance for installation, operation, and maintenance of three-pole oil circuit breakers used in high-voltage electrical systems, with specific applicability to the AHF-51-145KV-20KA-1200AMPERE model with serial number 25960 for the International Boundary & Water Commission (U.S./Mexico) under Purchase Order IBM 81-68.

The document covers critical operational procedures including unloading, hoisting, and storage of breakers; installation requirements for foundation preparation, grounding connections, and liftrod verticality; and detailed maintenance protocols for movable and stationary contacts, bushings, insulators, and electrical components. Key technical specifications include electrical resistance thresholds for liftrods and guide rods (minimum 10,000 megohms), movable contact member penetration standards (1¼ inches ± 1/16 inch), and pullrod measurement requirements (11⅜ inches ± 1/16 inch). The spare parts list identifies necessary components including stationary and moving contacts, gaskets, operating mechanisms, coils, auxiliary switches, pressure switches, thermal overloads, and bushing current transformers. The instructions emphasize mandatory safety precautions, including pressure relief procedures, prohibition of operation without oil in all tanks, and coordination with qualified operating and maintenance personnel. Permanent service records must document operation counters, maintenance facts, and equipment condition throughout the breaker's operational life.