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pressure getting drop while operating two functions simalteneously

pressure getting drop while operating two functions simalteneously

pressure getting drop while operating two functions simalteneously

I m Using 3 bank proportional valve, one is to run (two spooler drive motors), 2nd one is to run auto level wind motor & third one to operate wind arm cylinders. Connection through valve is parallel. while running main spool drive motors, maximum pressure reaches 200 bar & as I start up autolevel wind motor, Pressure get drops to 105 bar(which is the max operating press for auto level wind motor) How can I avoid this pressure drop??

Pump- 40lpm (press compensator + Load sensing)
flow required to drive the spool motors- 30 lpm
flow required to drive the auolevel wind motor - 4lpm  

RE: pressure getting drop while operating two functions simalteneously

Can you show us a circuit schematic?


RE: pressure getting drop while operating two functions simalteneously

Your load sensing pump is responding to the lowest load, just as it is designed to.

Load sensing compensators are power saving devices that will reduce the pump pressure to match the systems demand. The wind motor only needs 105 BAR to operate, that is what the compensator will respond to.

You need to jack up the 105 BAR by using a smaller motor, or remove the load sensing compensator from the pump.

A look over the schematic will help us to confirm this.



RE: pressure getting drop while operating two functions simalteneously

Either your pump can not deliver enough flow for both functions or the pressure sensing lines are not sensing properly.  The pressure at the pump should be the highest demand pressure plus the control's pressure demand.  The pump flow should be the sum of the demand flows.

See here for how load sensing works:


RE: pressure getting drop while operating two functions simalteneously

thanks ted/hydromech,

i think i shud better go wthhigh flow rated pump.  disconnectin LS line from proportional valve, problem remains & Pump is acting as a standard pressure compensator



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