Monday, June 3, 2013

SPQ13 TRACY

Did some hydraulic tests on the Bobcat E32 this week.  Cycle times for bucket curl and dump are 2.7 and 1.9 respectively.  Timed out to 2.4 and 1.6, contributing any error of that small amount to human error in running the stopwatch.

http://youtu.be/2MIvnn3orU4

Another test done was to locate the travel speed of one track in 60 seconds, then calculate and prove it.  Service manual specced the vehicle speed at 2.6 mph in second gear and high rpm.
Calcs:
  2.9mph x 5280ft=15312/60sec=255.2/14.5(track length in feet)=17.6 revolutions in 60 seconds
Proven - 18.25 revolutions counted (give or take some for human error)
  18.25 x 14.5 = 264.6 x 60 = 15877/5280 = 3 mph

http://youtu.be/BhMuCsSBd5E

Also hooked up an electronic psi gauge  to test the pilot pressure relief valve, located on the pilot line manifold.  Since testing requires the hydraulic fluid in the system to be at or above 150 F, we extended the boom out past relief pressure and it only took a few minutes for the fluid to quickly reach proper temp.  Used an infrared thermometer to verify temperature.  Once done, we jacked the rpms to full.  Test called out to engage the bucket curl and fully curl the bucket, with a target psi of 428 and a range of 406-450psi.  Pressure gauge read high 440's psi with a spike to 453 psi.


This past week I have grown very confident in my ability to read and understand hydraulic schematics, the hydraulic system itself, and a majority of its components.  Now that we are capping the quarter off with preventative maintenance, I was outside looking at the shops new Peterbilt and I was better able to understand and follow even things I've gone over before - like the drop down suspension and the small valve body hidden away under the frame.

Hours: 90
Total: 305

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