Choosing a motor for an attachment

[Andystephenson]

I have a standard flow T250 bobcat. I am looking at converting a 540 PTO flail mower to hydraulic. My machine has 21 GPM hydraulic flow and I’m not sure on the psi. I’ve been looking at a website called surplus center, and don’t know what size motor will work best for my machine and attachment. Anyone know what size motor I should use?

 

[Wayne440]

(off hand mental calculation, no warranty implied) If you want 540 RPM at 21 GPM, your motor will be about 9 cubic inch displacement.

 

[Andystephenson]

If you want 540 RPM at 21 GPM, your motor will be about 9 cubic inch displacement.

Ok that’s the biggest motor that’s they sell, does the psi have a big factor or should I not worry about that?

 

[Wayne440]

Pressure matters- for instance at 21 GPM, 1500 PSI= 18 horsepower, 2000PSI=23 horsepower, 2500PSI, then 32 horsepower.

All these are approximate calculations, but I'm sure you realize that a flail mower works differently with 18HP than with 32HP. If you do not have enough power, you won't be happy. I personally would not expect good performance from a flail on a standard flow machine unless cutting very light material. It probably isn't going to run over an overgrown fence line at walking speed.

(I claim no expertise, others with more experience feel free to join in)

 

[Andystephenson]

Pressure matters- for instance at 21 GPM, 1500 PSI= 18 horsepower, 2000PSI=23 horsepower, 2500PSI, then 32 horsepower.

All these are approximate calculations, but I'm sure you realize that a flail mower works differently with 18HP than with 32HP. If you do not have enough power, you won't be happy. I personally would not expect good performance from a flail on a standard flow machine unless cutting very light material. It probably isn't going to run over an overgrown fence line at walking speed.

(I claim no expertise, others with more experience feel free to join in)

 

[Andystephenson]

I would think I would be fine it’s not a huge flail mower and they do make them for skid steers. And I mean if an 85 hp tractor could run it I don’t see how my bobcat couldn’t.

 

[Wayne440]

Good luck. Let us know how it works out.

 

[Andystephenson]

Good luck. Let us know how it works out.

Will do

 

[MX727]

The 9 cu in motor is listed to run 470 rpm continuous. Get the 7 cu in, which is rated for 600 rpm.

 

[Andystephenson]

So should I go with that one?

The 9 cu in motor is listed to run 470 rpm continuous. Get the 7 cu in, which is rated for 600 rpm.