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Hydraulic Pumps

Hydraulic Pumps

Hydraulic Pumps

I have a pressure problem with an HPU.  My hydraulic power unit (consists of electric motor spinning a pump) is providing pressure to a mock up training device of an aircraft hydraulic system.  The pump is operated remotely from the training device.  It will cycle on and off with the pump compensator set at 3000 psi.  If i turn down the pump pressure to 2000 psi it will come on and stay on operating normally.  But it will not hold the 3000 psi load and trips my motor starter electrical circuit.  If i bring it up at 2000 psi and then while running crank my pump up to 3000 psi it will hold!?!  Do i possibly have a differential pressure problem?  any help would be greatly appreciated.

RE: Hydraulic Pumps

WAG:  You've also got a relief valve that's dumping flow at 3000 psi unless you sneak up on it.  I think air in the compensator line could do that.


Mike Halloran
Pembroke Pines, FL, USA

RE: Hydraulic Pumps

ok,an asynchronous motor,an hydraulic pump,a system pressure of 2000psi,a wish for 3000psi.i suggest to bypass suction/discharge until full rpm motor.

RE: Hydraulic Pumps

Thanks for the help!!  We finally fixed it by adjusting the differential pressure and then we had to change the compensator also.  Just dont know how the differential press changed!

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