1、Lessons Learned Entry: 0280Lesson Info:a71 Lesson Number: 0280a71 Lesson Date: 1993-07-12a71 Submitting Organization: JPLa71 Submitted by: R. K. MallisSubject: Galileo Power Subsystem Internal Voltage Drop Abstract: The high resistivity of nickel ribbon used for electrical interconnections within po
2、wer modules caused excessive voltage drops at subsystem power interfaces.Voltage drop analyses should be conducted to assure that voltages at the subsystem power distribution interfaces will always remain within the specified tolerances. Perform early subsystem bench level tests using representative
3、 external interface circuits to verify adequate performance. Description of Driving Event: During system tests, lower than expected voltages were measured at subsystem power interfaces indicating excessive voltage drop in either the interconnecting cables or the power subsystem. Subsequent testing i
4、solated the excessive voltage drop to the power subsystem. Power system subassembly tests demonstrated that the voltage drop was across the relay welded modules in the power distribution assemblies and was caused by the high resistivity of the nickel ribbon used for electrical interconnections in th
5、ese modules. These measured voltage drops were verified by JPL analysis.Lesson(s) Learned: The high resistivity of nickel ribbon used for electrical interconnections can result in an excessive voltage drop.Recommendation(s): 1. End-to-end voltage drop analyses should be conducted during the design p
6、hase, using flight Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-component characteristics, to assure that in the worst case condition, voltages at the subsystem power distribution interfaces are within the specified tolerances.2. Subsystem bench l
7、evel tests should be performed early using representative external interface circuits to verify adequate performance.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Flight Equipmenta71 Hardwarea71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 1987-04-17a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
