When designing hydraulically-driven machines you have to match the power able to be transmitted through the oil to the power at the engine and the power you want available at the motor shaft. The power in the oil can be calculated with the equation GPM * PSI / 1714 assuming perfect efficiency. (Hydraulic drives are anything but efficient but this makes the math easier and it will be in the ballpark.) Using the 3 gpm you said your pump puts out gives only about 5 horsepower at 3000 psi that can be transmitted through the hydraulics. It makes no difference what kind of motor you have on the other end, you simply won't get more than 5 hp out of it at this pressure. To transmit the full engine power at 3000 psi will require a pump that can put out more like 18 gpm. Next, use the equation DISPLACEMENT (in^3) = GPM × 231 / RPM to size the motor to run at the speed you want. You can also use the equation TORQUE (in-lb) = DISPLACEMENT (in^3) * PSI / 6.28 to determine the motor's torque output. Assuming you aren't hydraulic power limited the torque output from a motor is dependent entirely on displacement and pressure - the rotational speed doesn't factor in.
As Bob noted, you'll need some way to vary the flow rate to the motor. A flow control valve can be used but this would be an extremely inefficient way of doing it as the entire pump flow rate will be raised to whatever pressure the motor requires to turn, even if the valve is sending only a small percentage of the pump's flow to the motor. The rest of the engine's power will be converted into heat through the valve. A better way would be to use a hydrostatic pump and motor (also like Bob mentioned) where the pump's flow rate can be varied from zero to the maximum. However, when you get into hydrostatic drives you also need to provide filtered charge oil and a variety of other considerations. This would be a difficult project to get working right the first time for a person without a background in such things and the trial-and-error method could be prohibitively expensive given the cost of hydraulic components.
Upload one or more videos to your post. Photo filesizes should be less than 300K and Videos, less than 2MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - When Push Comes to Shove - by Dave Patterson. When I was a “kid” (still am to a deree) about two I guess, my parents couldn’t find me one day. They were horrified (we lived by the railroad), my mother thought the worst: "He’s been run over by a train, he’s gone forever!" Where did they find me? Perched up on the seat of the tractor. I’d probably plowed about 3000 acres (in my head anyway) by the time they found me. This is where my love for tractors started and has only gotten worse in my tender 50 yrs on this “green planet”. I’m par
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
