15nov04 td4 motor trouble


    Tiedown 4 failed on 12nov04. Breakers cb2,3?? were tripping. It was left in that position till 15nov04 because of an aeronomy run in progress. On 15nov04 the motor power supply was  replaced. The dac signal conditioning board also had some blown chips so it was replaced. After the replacements the following problem was still noticed.

This occurred more than once. The plots show one of these occurrences:     It is not clear why this is happening. It could be that the brakes are not releasing properly (but you can hear the brake relay change way before the overspeed condition. This problem occurred at different positions of the jack so it is probably not a bad spot in the jack.
    On the 16th we switched little stars, dac board to not avail. We had trouble with the little stars keeping the configuration parameters in eeprom when we cycled the little star power. After lunch some of the breakers were tripped again. Luis had to disconnect the box fan to get them to not trip. After that he installed another little star and everything worked (at least up till now...). So it was some kind of short in the system ???
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