220121:azswing with el=60deg

    On 21jan22 carlos and wilson were checking the limit switches on the 12meter when then heard a noise as the azimuth motor passed by the ladder that is used to access the hub. Later that day i did an azimuth swing to take a look at the motor torques.
The swing used:

•  elevation set to 60 deg
• telescope moved -180 to +360 deg at .5 deg/sec (tracking mode) and then 360 to -180 at -.5 deg/sec
• Since we moved -180 to 360, the region -180 to 0, (or 180 to 360) is visited twice on each swing.
  

The telescope position, currents are recorded once a second. The motor current measures the torque applied.

The plots show the motion (.ps) (.pdf)

• Page 1:
  
• Top: azimuth position vs hour of day
• middle: measured azimuth velocity vs time
• bottom: azimuth motor currents (eg torques) vs time of day
• black is the master motor
• red is the slave motor.
• The sign of the current changes with azimuth direction.
  
• moving  CW:
• the master current is stable, the slave motor1 current varies a bit
• moving CCW:
• the slave current is stable while the master varies some
• I don't know the relative locations of the master,slave motors.
• My guess is that CW the master is pushing, and CCW the slave is pushing.
• Page 2: currents
• Top: master current vs azmuth position.
• The upper line is moving CCW
• the lower line is moving CW
• Middle: slave currents
  
• Bottom:
• motor currents vs azimuth velocity

When  the azimuth encoder is 306 deg (-64)  one of the azimuth motors is over the pedestal door. Moving CCW then moves the motor closer to the ladder. Looking at the current vs azimuth, there is no large jumps from -64 to -74 degrees.

processing:x101/220121/aztorq.pro