Need Hydraulic Motor Advice for Stump Grinder

[juddspaintballs]

OK. I guess my cutter wheel powered with engine driven belts is too expensive to add hydraulics to even though the machine is self-propelled hydrostatically. I'll tell Rayco, Dosko, Carlton, etc. that they're doing it wrong.

Obviously using hydraulics to grind a stump works, but cutting down a tree with an axe works too. Most hydraulic driven units don't work as well as their comparable engine driven units because of cutter speed.

 

[CJONE]

OK. I guess my cutter wheel powered with engine driven belts is too expensive to add hydraulics to even though the machine is self-propelled hydrostatically. I'll tell Rayco, Dosko, Carlton, etc. that they're doing it wrong.

Obviously using hydraulics to grind a stump works, but cutting down a tree with an axe works too. Most hydraulic driven units don't work as well as their comparable engine driven units because of cutter speed.

I didn't know we were talking about adding hydraulics to anything, this is the primary grinder head correct? Ground drives are a different story and I will let every manufacturer know on their processors that they can't operate their saws with hydraulics either!! fun fun CJ

 

[J_J]

Looking through a lot of stump grinder disc speeds, it appears that most of them run around 800 rpm to about 1500 rpm.

So, given equal HP, and using the same cutting wheel, the direct driven hyd disc and the engine should cut about the same. The FPM rotation of the disc and type cutter could determine the efficiency of either.

The hyd motor driven disc will have about the same torque through the rpm range.

The engine driven cutters probably reduce the speed to around 800 to 1500 to gain more torque and efficiency.

 

[oldnslo]

Without question belt driven stump cutters put more of the engine power to the ground than hydraulic driven units. I would estimate 15% power loss with hydraulics. Belts require that the drive pulley and driven pulley always remain aligned which can make the machine more cumbersome Vs running two or three hydraulic hoses out to the cutter head.

Their unquestionably advantages to both mechanical drive and hydraulic drive. For a stand alone engine driven direct drive may be the best choice. As an attachment for a skid loader hydraulic is usually the best choice.

I believe the OP was looking at this as an attachment for his tractor or skid loader so hydraulic is the most economical choice.

 

[oldnslo]

Woodland,
Is this going to be used once every few weeks or months or as part of business? if infrequent duty then a lesser quality motor may last for years, if daily or weekly use I would recommend a top quality motor. One example is a Rexroth A2FM bent axis motor. I see a lot of these used on mulcher heads and larger stump grinders.

google RA91001 for the data sheet on these motors. Displacements of 80, 90, 107 cc/rev should be close to what you are looking for.

 

[woodlandfarms]

Infrequent. Not at all in a business environment.

 

[CJONE]

Without question belt driven stump cutters put more of the engine power to the ground than hydraulic driven units. I would estimate 15% power loss with hydraulics. Belts require that the drive pulley and driven pulley always remain aligned which can make the machine more cumbersome Vs running two or three hydraulic hoses out to the cutter head.

Their unquestionably advantages to both mechanical drive and hydraulic drive. For a stand alone engine driven direct drive may be the best choice. As an attachment for a skid loader hydraulic is usually the best choice.

I believe the OP was looking at this as an attachment for his tractor or skid loader so hydraulic is the most economical choice.

I have always been told 10% per motor/pump then flow loss. Now from experience Piston units are about 15-20% total and gear units can be anywhere from 20-35% for the system of course depending on who plumbed it and how many motors/pumps involved. And to be honest depending on rpm and pressure I have seen over 50% loss if the equipment is not in it's rated use range. Anyway like you said for the o/p it is the most cost effective. CJ