On Fri, 02 Jul 2004 09:06:23 -0400, GeorgeB wrote:

On Thu, 1 Jul 2004 14:35:53 -0700, "PAW" wrote:

Here's the problem (IMO) with your response; I was asking about using
hydraulic motors. Several took my 3200 RPM speed as set in stone. I was
ONLY pointing out the fact Eaton has a full line of *lightweight piston
motors* that will handle speeds *UP TO* 3600 RPM at some decent torque
figures. A Mazda 13b is more than capable of producing the horsepower (plus
it's a lightweight water cooled engine) to provide the flow and PSI for
these little motors.

Anyhow, thanks for the "input". I'll stick with asking the engineers at
Eaton my questions because I'm obviously getting nowhere here. For the two
gents that provided information (Corky and Bob), Thank you.

An issue is that a hydraulic drive is less efficient than direct,
belt, or gear. There will be the additional weight of the pump and
motor. There are 2 additional points of failure, the pump and motor.
If you elect to drive the motors in series, the first in the string
will run "slightly" faster than the 2nd (assuming a case drain) if
they are otherwise identical. You have fluid lines to concern
yourself with. The first, if in series, MAY not like having its
outlet at "half" system pressure. Maintaining positive suction head
will require consideration.

I design and provide technical support for electrohydraulic systems
for a living, and this is not a place that I owuld recommend their
use.

George

Maybe you can answer a question I've had for sometime. What is the
relative efficiency of hydraulics, belts, gears and chain drive?
You've given the hydraulic answer. Care to take a stab at the others,
please?