Relief Valves...

[Robert128]

Hey Guys,
I am trying to locate some relief valves for a project that I am working on. I am wondering if someone can give me some info.
This is an old Reel Mower that I am customizing and I need to know where the R3 relief valves are or what they would look like. Here is the schemata:

What I want to do is remove them or replace them with a higher psi valve. There are 2 Relief valves for the entire circuit that are set at 2750 psi - So I am going to let these two work for the entire circuit as a safety.
They are plug in type valves in a block/selenoid set up. But I just cannot find those smaller relief valves - Could they be inside of the hydraulic motors themselves?:confused2:
Thanks a bunch!

 

[AKKAMAAN]

The scematic is missing some info....the dots that connects lines...but it looks like all four pumps P1-P4 are somehow in the same unit....and probobly on the same shaft line???
Anyway I circled the relief valves
P1-R1B
P2-R1A
P3-R7 (in the pump unit)
P4-R6 (2 RV's) this is the bi directional hydrostatic drive pump

They, the Rv's, should be cartridge valves, that have to be replaced, to change pressure setting

The #R3 Rv's are all integrated with the mower motors...M1, M2,M3, M4 and M5

 

[Stonehaller]

Those R3 valves are cross over relief valves that will limit the motor torque. One of the functions is to protect the motor and drive line from excessive torque due to inertia when you stop the motor. The other relief valves offer no projection for this torque due to stopping. Not wise to just eliminate the R3 valves. If you increase the R3 pressure setting, make sure the motors and drive line can handle the higher torque.

The scematic is missing some info....the dots that connects lines...

Lines that cross without a little loop are connected.

 

[AKKAMAAN]

Those R3 valves are cross over relief valves that will limit the motor torque. One of the functions is to protect the motor and drive line from excessive torque due to inertia when you stop the motor. The other relief valves offer no projection for this torque due to stopping. Not wise to just eliminate the R3 valves. If you increase the R3 pressure setting, make sure the motors and drive line can handle the higher torque.



Lines that cross without a little loop are connected.

yes I see those loops....I am just so "spolied" reading ISO std schematics....

Good fill in about the torque on motors....

 

[Robert128]

Thanks so much for the information. It may be that I am just trying to squeeze to much torque and speed out of those motors. May have to fall back and punt......:laughing: