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Specification, Measurement, and Control of Electrical Switching TransientsThere have been several instances of susceptibility to switching transients. The Space Shuttle Spacelab Remote Acquisition Unit (RAU-A standard interface between Spacelab payloads and the Shuttle communications system) will shut down if the input 28 Vdc bus drops below 22 volts for more than 80 gs. Although a MIL-STD-461 derivative CS06 requirement was levied on the RAU, it failed to find this susceptibility. A heavy payload on one aircraft sags the 28 volt bus below 20 volts for milliseconds. Dc-dc converters have an operating voltage. A typical 28 Vdc-to-5 Vdc converter operates within tolerance when input potential is between 17-40 Vdc, A hold-up capacitor can be used to extend the time this range is presented to the convener when the line potential sags or surges outside this range. The designer must know the range of normal transients in order to choose the correct value of hold-up. This report describes the phenomena of electrical power bus transients induced by the switching of loads both on and off the bus, and control thereof.
Document ID
19990116837
Acquisition Source
Marshall Space Flight Center
Document Type
Contractor Report (CR)
Authors
Javor, K.
(EMC Compliance Huntsville, AL United States)
Date Acquired
September 6, 2013
Publication Date
September 1, 1999
Subject Category
Electronics And Electrical Engineering
Report/Patent Number
NASA/CR-1999-209574
M-937
NAS 1.26:209574
Report Number: NASA/CR-1999-209574
Report Number: M-937
Report Number: NAS 1.26:209574
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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