1、Lessons Learned Entry: 0742Lesson Info:a71 Lesson Number: 0742a71 Lesson Date: 2000-02-29a71 Submitting Organization: JSCa71 Submitted by: Larry GreggSubject: Verification of Nominal Conditions After Restoration of Power Description of Driving Event: On May 16, 1994, an AMDAHL 5995M mainframe comput
2、er overheated at approximately 8:20 AM in the Software Production Facility (SPF) in Building 30 at JSC. Physical damage to the computer due to this overheat was estimated at $669,000. This overheat occurred due to an inadvertent miswiring of a circuit breaker after a routine power outage and mainten
3、ance of the breaker. The quality inspection failed to check for the proper rewiring of the circuit breaker. The miswiring caused a phase rotation of the power, which in turn caused fans cooling the AMDAHL 2550 to turn backwards. Power isolation and monitoring equipment that could have prevented any
4、impact from the phase rotation was not properly utilized. This led to insufficient cooling of the AMDAHL 2550 which resulted in the overheat and subsequent damage.Lesson(s) Learned: Personnel operating critical equipment should not assume that the support environment is intact after an outage. They
5、should operate instead under the assumption that something might go wrong.Recommendation(s): Appropriate precautions and checks should be made to ensure that critical equipment, when powered, will function as intended. An example is phase reversal which occurred the wiring during installation or mai
6、ntenance was incorrect, causing equipment to function in reverse.Evidence of Recurrence Control Effectiveness: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Scien
7、cea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Communication Systemsa71 Computersa71 Configuration Managementa71 Environmenta71 Energya71 Facilitiesa71 Flight Operationsa71 Flight Equipmenta71 Ground Operationsa71 Ground Equipmenta71 Hardwarea71 Policy & Planninga71 Safe
8、ty & Mission Assurancea71 Test Articlea71 Test Facilitya71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2000-04-11a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
