DC Motor for Hydraulics?

I did some searching on hydraulic pumps and determined you will need a motor that will output between 25 and 26 hp with at least 1800rpm depending on the pump you use. Doing a quick search on Globalspec for a DC motor with these specs comes up with 153 products. I don't know what you consider a fairly low voltage, but you can modify the search and put in your requirements.

Hope that helps you out in your project

You may try the Bosch Rexroth pumps, the lowest of them will satisfy your pump needs of 12 gpm (actually delivers 16 gpm, but they are variable flow pumps), the installed kW is a minimum of 15 HP to a max of 125 HP.Generally all the pumps are designed for a max pressure of 400 BAR, so your required pressure of 3000 PSI (roughly 206 BAR) is not a problem. But why do you need a DC motor? (To vary the RPM/ Flow?) The conventional hydraulic systems used to employ constant flow pumps with electric motors which can vary the RPM (DC motors) to vary the flow. But the newer systems involving variable flow pumps (with swash plate arrangement) employ constant RPM AC motors instead of DC motors with constant flow pumps. Now it is your pick, if you still insist on a DC motor then go ahead with a constant flow pump!

I think that you are missing the biggest factor.

POWER.

Consider the munbers involved.

hp= (psi x gpm) /1714

3000psi x 12gpm / 1714 = 21 HP

21 HP = 15,700 Watts

Amps = watts / volts

15,700Watts / 12 Volts = 1,308 Amps

Please provide application and load. In hydraulics there is generally a way around things.

GPM is speed. If you dont need this speed then you can save a lot of horsepower.

The standard duty DC Hydraulic pumps from Fenner Stone (now SPX Stone)& Haldex are about 1.2 -1.5 Gpm @ 2500 -3000PSI = 2HP. These are cheap and common. Use the POWER formulas and see if you can stay below 2 HP to save money. If this is what you have to have, then seriously look at a portable gas powerpack, PTO or other options. DC is not a good idea for this range. The comments about 15-120 HP motors are only true in AC applications.

The formula I used does not account for any losses. Generally 12- 20% depending on duty cycle, temperature,etc. I use 15% unless it is a high duty cycle, then 20%.

21HP x 15%= 24 HP. Gas engines ballpark cost $100 per horsepower.

A good source of cheap DC hydraulic pumps are those designed for the steering pumps on lorries. The flow rates are relatively small, but they could be ganged together on a common tank.