REG NASA-LLIS-0581-1997 Lessons Learned Unstable Small Electronic Dynamic Load Banks Over Long Couple Distances.pdf

1、Lessons Learned Entry: 0581Lesson Info:a71 Lesson Number: 0581a71 Lesson Date: 1997-12-22a71 Submitting Organization: JSCa71 Submitted by: Edward ChamradSubject: Unstable Small Electronic Dynamic Load Banks Over Long Couple Distances Description of Driving Event: During testing of a electrical power

2、 generating device known as a “fuel cell“ it was discovered that the electronic dynamic load bank went into oscillations and became very unstable when an attempt was made to utilize it as a “load“ for the fuel cell.During post test evaluation it was discovered that when these load banks are long cou

3、pled to the power supply their performance is erratic. When short coupled they perform as programmed. The question becomes at what length coupling does the problem occur. Presently evaluations were only made at three lengths: five (5) feet, twenty (20) feet, and forty feet per lead. At five feet no

4、problems were noted, at twenty feet and forty feet the load bank was unstable. Research of available literature concerning this load bank does not reveal this problem. Consultations with the manufacturer indicated they were aware of some problems associated with small dynamic load banks using long c

5、oupling leads and that this is a characteristic of this type of load bank (small electronic dynamic load banks).This instability has been observed in small electronic dynamic load banks; larger dynamic load banks do not seem to exhibit this phenomenon, and resistive load banks are not prone to this

6、phenomenon. The correlation of this phenomenon to the couping length is still under investigation. A Government-Industry Data Exchange Program (GIDEP) alert has been recommended.Lesson(s) Learned: Load banks must be evaluated during development and test for reliable performance at coupling lengths e

7、qual to or greater than intended in the final test or operational configuration.Recommendation(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-If use of this type of load bank is required, it is recommended that further evaluation to determine at

8、 what length coupling does the load bank performance become erratic. Also, it should be tested with the actual coupling required prior to utilization as a critical load. The reporter has reverted to use of resistive load banks with no recurrence of this phenomenon.Evidence of Recurrence Control Effe

9、ctiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Energya71 HardwareAdditional Info: Approval Info: a71 Approval Date: 1998-01-30a71 Approval Name: Ronald A. Montaguea71 Approval Organization: JSCa71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-