here is show some pics of KOMATSU PC800-7 in china
komatsu pc800-7 excavator
For a Machine that size it sure don't have very big feet.
hydraulic pumps look like the ones used on the dash 5 excavator
really? but it definately is -7, it is original from Japan, and the serial no plate and chassis no show it is dash 7...
I believe they stayed with the open center load sensing system on the machines bigger that PC400. The electronics package is bound to be different though. Thanks for the photos!
The Pc800-7 has OLSS system,so has the Pc800-8, the early Pc800-8 has the same pumps set up as the -7 ,but the newer Pc800-8R has a totally new pump set up with one huge twin hydraulic pump and electronic jet sensor that electrically control the hydraulic pump. the valve blocks are very similar to previous pc750/pc800 set up.
Looks like they are working in rocky material. Wide pads get all bent up in rock.
Can we consider the OLSS as a negative flow control?
All the load sensing open center control valves that I have seen are negative control. All the closed center load sensing control valves I have seen are positive flow control.
There can be open center valves along with positive control. Put sensors on the pilot lines that tells the ECU how much flow that is requested and regulate the pump electronically according to that.