Page 31 of Quality Tools for the Energy Industry by Cooper Power Tools

mountable power motors introduction air motor selection cooper power tools air motors are engineered for great flexibility convenience and reliability dotco buckeye and gardner-denver air motors cover a wide range of uses where compressed air is advantageous powering air driven machinery raising foundry copes and drags rotating a turntable mixing paint powering cranes steering fishing boats valve actuation or power source for mechanical hands 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 m 3 /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 cooper power tools 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 0.19 x torque ft lbs x rpm 1000 1000 x hp 0.19 x torque ft lbs rotary vane air motors cooper power tools offers two types of rotary vane air motors the large gardner-denver mr series 1.0 to 7.5 hp and small to medium sizes 14 to 2.3 hp in the dotco buckeye and gardnerdenver product lines all motors feature durable construction with precision heavy-duty bearings throughout and multiple blade rotors for smooth power there is a wide range of speeds and torques as well as a choice of foot face or flange mounting these motors require only air line lubrication for long trouble-free service mount the lubricator as close to the motor as possible these motors perform satisfactorily in high temperature areas up to 200°f 93° c rotary vane axial piston these small lightweight gardner-denver motors are ideal for installation in close quarters the rugged construction and precision manufacturing of these motors allows long life with minimum maintenance generous size spindle bearings permit overhung weight on spindle with no external support high torque is an inherent characteristic of piston type air motors making them especially desirable for applications involving heavy starting loads the overlap of power impulses in axial piston air motors provides even torque and full power in either direction of rotation these motors should be operated under load and horizontally axial piston motors are ideal for start stop operations it is not recommended that they be operated at speeds greater than 75 of free speed their enclosed type construction allows operation in corrosive or dusty atmospheres these motors perform satisfactorily in high temperature areas up to 200° 93° c grease fittings are provided for lubrication it is recommended that air lines be equipped with filters and lubricators mount the lubricator as close to the motor as possible rotary vane horsepower hp speed rpm axial piston 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 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 4 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 radial piston heavy-duty construction make these motors suitable for continuous operation the counterbalanced crankshaft is supported by antifriction bearings a slinger distributes oil to all moving parts of the motor oil level and drain plugs are easily accessible high torque is an inherent characteristic of piston type air motors making them especially desirable for applications involving heavy starting loads the overlap of power impulses in radial piston air motors provides even torque and full power in either direction of rotation at least two pistons are always on a power stroke these motors should be operated under load and in a horizontal position it is not recommended that they be operated at speeds greater than 75 of free speed these motors perform satisfactorily in high temperature areas up to 200° 93° c it is recommended that air lines be equipped with lubricators mount the lubricator as close to the motor as possible note listed in this catalog are our more popular models only refer to catalog sp-104 for a complete listing of models available radial piston torque and horsepower curves may be interpreted for approximate performance at other psi pressure 58 59

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