gregorian amp 32 failure nov13

• plots are made of .2 hour sections (12 minutes)
• For each section there are 2 frames.
• The top frame of the pair shows the za vs time
• the 2nd frame of the pair shows the torques vs time for the 8 motors
• Each motor in color coded.
• Page 1:
  
• 0 to .2 hours
• the dome was moving from 14 to 16.5 deg za.
• The dark red trace is motor 32 torque.
• HB means that a hydraulic brake is connected to this motor pair.
• .2 to .4 hours
• mot32 was dropping out until .25 hours.
• At .25 hours the domed stopped moving.
  
• The torque from mot32 went to 0
• At .29 hours the dome started moving uphill fast.
• The mot32 torque was output ok
• At .3 hours the za rate slowed down, the torques started jumping again.
• At .315 hours the dome started downhill
• moving downhill, there are no jumps (in this za range)
• At .375 hours, the dome started uphill again , mot32 started dropping out again
• Page 2:
  
• .4 to .6 hours
• Dome moved down and the up (must have been close to transit).
• Moving downhill, there are no dropouts. Moving uphill there are. this was repeatable.
• 2.65 to 2.85 hours
• at 2.69 th motors were turned on.
• no torque from mot32 while dome sits still
• At 2.75 start moving uphill at a fast rate. No mot32 dropouts.
• Page 3:
• 4.40 to 4.60
• mot32 torque  starts oscillating when turnaround approached (at 4.5 hours)
• when starting back up, dropouts start.
• 4.6 to 4.8
• moving slowly uphill.
  
• dropouts the entire time

Summary:

• moving uphill at a slow rate, mot32 had little torque with multiple dropouts
• rapid uphill motion had more normal torque output for motor 32
• moving downhill had normal torque until the velocity approached 0. The torque then began to oscillate
• When sitting still, the torque would go to 0 (rather than sit and the normal holding torque).
• Looking at previous days, this problem with motor 32 has been occurring since 12nov13.
• on 26nov13 around 14:00 the amplifier for motor 32 was replaced.
  
• The motor has performed normally (at least for the 3 hours since the replacement).
• We should not have run for 2 weeks with the amplifier malfunctioning...
  
• We need to display the torque vs time in the control room (both dome and azimuth)
• The programs to do this exist,  we just need some video monitors to display them on.