Gregorian amp/mot 22 failure jun13


Layout of gregorian drive system
12jul13 failure, drag link comes off

June13 failures
When the failures occurred
Plots of the system status during the failures.
Damage found after the 18jun13 10am failure

     There were a number of motor amplifier failures in mid June 2013. They mainly involved amplifier 22.

layout of drive system (top)

The Gregorian  dome drive system consists of:
The picture shows how the upper 4 motors are connected to the dome:
layout of motor

12jul13: drag link comes undone, connection plate bent.

    The drag link for motors 21,22 was disconnect around 22:00 hours on 12jul13. It appears that the dome was moved after this occurred. Looking at the pictures (below) it looks like the motor pig ended up pushing on the hydraulic brake equipment.

    plots of gregorian status for 12jul13 (.ps) (.pdf)
plots of the damaged connection plate

jun13:When the failures occurred (top)

    The failures occurred 15,16,17,and 18jun13. The one second sampling of the drive system status was used to determine the different failures.

Plots of the system status during the failures  (top)

    The below plots were made using the status info recorded around the various failures. This status info is sampled once a second. The pages contain:

status plots
(.ps)  (.pdf)
m22 not ready
m22 torque increases 2 secs before failure
(.ps)  (.pdf) m22 not ready
m11,12,22 fault. 21 ok
m22 oscillating for 6 minutes prior to failure
(.ps)  (.pdf) amp 22 not ready
all torques increasing. m22 highest .. about 43 ft-lbs
18jun13 2am
(.ps)  (.pdf) amp 22 not ready. all others ok.
18jun13 10am
(.ps)  (.pdf)v amp22 torque increased 1-2 secs before failure
dc1 bus fault (pwrsup bus voltage > 360 Volts)

The next set of plots has the position, velocity, and torques for all 5 failures (.ps) (.pdf):

processing: x101/130618/

damage found and corrections after 10am 18jun13 failure  (top)