Air Motor FAQ's
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Air motors, also called pneumatic motors, use linear or rotary motion to translate compressed air into mechanical work. From their safety components to their ability to work faster and harder than other motor types, they offer significant benefits for a variety of industrial processes.
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Q: What is the difference between a four vane and eight vane air motor?
A: Eight vane air motors are used when minimum speed or in inching applications are needed.
Rotation
Q: What oil do I use?
A: Gast air motors require a 10 wt detergent oil; Gast AD220.
Q: How much oil do I use?
A: One drop of oil for every 50 cfm of air used.
Q: How close should the lubricator be?
A: Gast recommends a filter, regulator and lubricator be placed within twenty inches of the air motor.
Q: What line size should I use on my Gast air motor?
A: The air line should be the same size as the port or one size larger.
Q: Can I mount the air motor in any position?
A: The Gast air motor can be mounted in any position.
FOUR VANE OR EIGHT VANE.
1.) Four vane units meet most requirements, but for more precise inching control and minimum blow by in applications where the motor is operating in a stalled condition, specify eight vane models.
2.) Additional vanes will not increase maximum starting horse power but will increase average starting torque by approximately 25 percent.
3.) Additional vanes will actually decrease the horsepower of an air motor under running conditions, while the flow remains the same. The motor is less efficient and will require more air per horsepower developed.
4.) Additional vanes, however, will decrease the blow-by up to 30 percent at stalled conditions.
5.) Additional vanes in a motor being operated under stalled conditions, most of the time (such as when used as a power spring) will cut down on blow-by of air and reduce air consumption.
6.) Additional vanes in an air motor, used in an inching application (such as a hoist) will, because of decreased blow-by, permit better inching control.
7.) Additional vanes in an air motor will permit operation at lower speeds than recommended for 4 vane air motors.
GAST MOTOR SIZE. ( OIL SERIES )Air motors differ in many ways from other power sources. These unique operating characteristics must be considered when selecting an air motor for a particular job. It is easy to change horsepower and speed of an air motor by throttling the air inlet. Therefore, the best rule of thumb for selecting an air motor is to choose one that will provide the horsepower and torque needed using only two-thirds (2/3) of the line pressure available. The full air line pressure will then be available for overloads and starting.
NON-LUBRICATED AIR MOTORS. ( NL SERIES )For air motor applications where contaminated exhaust cannot be tolerated in the workplace, non-lubricated air motors, the NL series, provide the solution. Advantages: No oil expenses, Rugged and reliable, Performance flexibility, Corrosion resistant, No periodic inspection.
OUTPUT POWER, TORQUE & AIR CONSUMPTION VS SPEED.The output power of an air motor is relative to speed and to air line pressure.
DO I NEED AN FRL.
FRL stands for Filter Regulator Lubricator. NL Series Oilless Motors do not require the (L) Lubricator section that puts oil in the air line. For NL Oilless Air Motors you only need a FR, Filter Regulator.
The FRL letters stand for: (F) Filter that cleans the air, (R) Regulator that regulates air pressure and controls the speed (R.P.M.s of the air motor), (L) Lubricator that installs small amounts of oil into the air line to lubricate the air motor. Note: be sure to use only Gast AD220 Air Motor Oil as it meets and exceeds all requirements in assisting in long air motor life and durability. Clean air and quality oil are key in long air motor life. Using ambient air (non filtered air) will dramatically reduce air motor life, many times by half. Off the shelf oil may reduce air motor life as well if it cannot with stand higher temperatures and load. When the oil starts to break down it will start to clog the air motor and quickly create wear on the vanes in the motor.
IF MY AIR MOTOR NEEDS OIL, WHICH OIL SHOULD I USE.
Gast AD220 Air Motor Oil is highly recommended. Typically 1 drop of oil may be needed per minute of motor operation. Air motor size, R.P.M.s and load may decide the amount of oil needed.
TORQUE VS SPEED.1.) An air motor slows down when load increases . . .
at the same time its torque increases to a point where it
matches the load. It will continue to provide increased torque all
the way to the stalled condition, and it can maintain the stalled
condition without any harm to the motor.2.) As the load is reduced, an air motor will increase speed and the
torque will decrease to match the reduced load.3.) When the load of an air motor is either increased or decreased,
speed can be controlled by increasing or decreasing air pressure.4.) Starting torque of an air motor is lower than running torque. While
this provides smooth, low-shock starting, it is necessary to have
additional air line pressure for starting under heavy loads.
AIR CONSUMPTION VS SPEED.Air consumption increases as speed and air pressure is increased.