Cleco 2019 Digital Catalog - Flipbook - Page 129
Air Motors
Air Motor Selection
To assist in the selection of an air motor, we need any two of the following three items of information:
1. Horsepower required.
2. Speed (RPM) required against load.
3. Work load expressed in foot pounds
or inch pounds of dynamic torque
(moving torque load).
As air motors are dependent upon input air pressure for performance, these factors must also be considered:
1. Air pressure (psig or bars) at motor
location.
2. Pipe size of air supply system to
assure adequate volume (cfm or m3 /
min) so as to minimize line loss (air
pressure drop during motor operation).
3. Plant air system pressure may
vary during the day due to use by
other equipment; therefore, base the
selection of the air motor on the lowest
psig or bars that can be expected.
Then, by using a pressure regulator
in the line at the motor, a uniform air
supply is assured.
In applications of intermittent short service, Cleco air motors can be operated over the complete range indicated for each
without harm or significant wear. In applications involving sustained continuous operation for long periods, however,
some guidelines are suggested. Do not operate piston and MR motors at more than 75% of free speed. Consult the
factory for applications requiring continuous operation of rotary vane motors at maximum HP or for any applications
requiring vertical operation of these motors. Review service manuals carefully.
For two known and one unknown, the following formulas can be used:
Ft. lbs. Torque = 1000 X HP
0.19 X RPM
Horsepower (HP) = 0.19 x Torque (ft. lbs.) X RPM
1000
Speed (RPM) = 1000 x HP
0.19 x Torque (ft. lbs.)
When working with Newton meters (Nm), substitute .0258 in place of 0.19 in the formula.
Use the performance charts provided for each motor size and type for obtaining this same date procedure:
1. Select operating
pressure.
2. Select torque
required from the left
hand scale.
* Torque and horsepower
curves may be interpreted
for approximate
performance at other psi
pressure.
3. Extend that point
position across chart
until it intersects with
torque performance
curve of the selected
pressure.
4. Draw a vertical
line from the above
mentioned intersection
to the corresponding
motor scale at the
bottom of the chart
to determine the
operating speed at the
required torque and
psig pressure.
5. Extend the vertical
line until it intersects
the horsepower curve
of selected operating
pressure and read
horsepower from the
motor scale on the
right side of the chart.
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