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Description of Driving Event:

During testing of a electrical power 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 coupled 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 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 coupling 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 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.