what size hydraulic motor

[washita]

cut trencher boom off of 1936 archer trencher welded qa plate to it so I can use it on my 425 powertrac tractor puts out 8gpm at 1500 psi trenching boom has 40inch depth capacity 4inch wide chain originally powered by a 10hp kohler motor comments / suggestions unfortunately fundsability eliminate me from buying a new trencher from tazewell besides it just one job for the family thanks

 

[Yankee Clipper]

Washita,

Hydraulic horsepower is calculated by the formula: HP = GPM x PSI / 1714 - this assumes a 100% effiiciency which is not reality but can help you size the motor for your pump.

The system requires 7 HP at 100% - at 90% about 7.7 HP so your 10 HP Kohler should be good enough for similar performance as the mechanical drive.

To size the motor, you will need to know the pump displacement - foundon the tag or model number in cc/rev or in3 per rev. Again, once that is known, it is algebra to balance the pump flow to the motor RPM.

Don't forget the motor at 90% will make the pump / motor efficiency drop to 81% - again heat will make it less and leaks moreso. All that to say, talk to someone who knows what you need and what they have to work with it for a good match.

Good luck!