Q. Do these motors have to be lubricated?
A1. Yes. Motors need to be automatically lubricated with an inline luber. Gast recommends using Gast #AD220 or SAE 10W high
detergent engine oil at a rate of either one drop per continuous minute or 1 drop per 50-75 cubic feet of air usage. (If no equivalent oil is
available, a 10W30 detergent motor oil may be substituted.) Gast does NOT recommend synthetic blend oils. For food processing
applications use White Rex 425 FDA food grade motor oil. Motors may also be manually lubricated: Shut down motor every 8 hours of use,
disconnect inlet air line and place 10-20 drops of oil directly in the inlet port.
A2. And No. If your application demands a lube-free model you can order a NL Series motor that operates entirely without lubrication.
(Sorry, we no longer offer the NL Series.)
Q. Is there really any difference between a "Reversible" rotation motor and a "CW" or "CCW" motor?
A. Yes there is. There are differences in both the body and vanes of the different rotation models. You can not buy a CCW (counter clock-
wise rotation) or CW (clock-wise rotation) motor and then decide later that you want to rotate in both directions and just change the plumbing
to get a reversible motor. If there is any doubt in your application whether or not you will need to rotate in both directions, then order a
reversible motor. A reversible motor can be used in a unidirectional application but a unidirectional motors can not be used in an application
where the motor needs to turn both directions.
Q. I don't see a "Reversible" version of the NL (oil-free) Series listed? Why not?
A. Unfortunately Gast does not currently make a reversible oil-free version. You can only buy a CW or CCW rotation NL motor. (Sorry, we
no longer offer the NL Series.)
Q. Should I order a 4-vane or an 8-vane motor?
A. Four-vane motors are suitable for most requirements. Select an 8-vane version when you need more precise inching control (very
slow motor speed) or when trying to achieve minimum blow-by in applications where the motor is frequently operated in a stalled condition.
Q. Can I run these motors in a cold environment?
A. Gast air motors are rated for use down to 32 degree F. Note that condensation in the motor may freeze at lower temperatures possibly
causing the motor to lock up until thawed. If inadequate lubrication is present in a lubricated style motor, this condensation may also cause
Q. How much air do these motor use when running?
A. Each motor has an air consumption chart included in the specification page. Increasing pressure and increasing speed both increase
air consumption so you must use a chart to determine air usage for your application. Keep in mind: air motors use a significant amount of
air and you must insure that you have a sufficient air source (compressor/tank), adequate piping coming to the motor and large enough air
preparation equipment (filter, lubricator, regulator etc). As a general rule, air motors consume about 30-35 CFM per horsepower produced.
It takes a 7-10 hp compressor to continuously feed an air motor producing 1 horsepower. In many cases the air motor usage is not
continuous (or is at a slower speed or lower pressure) so a much smaller compressor is completely adequate. Intermittent use also can be
handled with a smaller compressor if the tank size is big enough.
Q. How noisy are air motors?
A. These air motors have the inherent rotary vane “whine” and are supplied with an exhaust muffler to attenuate this noise. Further noise
control can be accomplished, if needed, through exhaust line routing and or additional muffling. Note that long exhaust lines of inadequate
size could diminish performance.
Q. Will an air motor run at the same speed once the pressure is set?
A. One advantage of air motors is that their speed can be easily changed over a wide range by adjusting the pressure or air flow to the
motor. Keep in mind, though, that air motors are both pressure and load sensitive with regards to speed. If you set the pressure going to an
air motor to achieve a certain speed with a given load, and later make a significant change to the load you will see some motor speed
change. The charts on the motor specification pages will clarify the motor speed that you can expect at given pressures for any load that is
Q. So what's the difference between the Gast 1AM and the Gast 1UP version air motors?
A. The 1UP is a slower speed version of the 1AM. Applications that need the smaller air motor size but with less speed than the 1AM can
use a 1UP. The 1UP has more torque at intermediate speeds. Note that the 1UP is rated at 80 psi max., is slightly heavier and is
dimensionally longer than the higher speed 1AM.
Q. Are Gast motors field "rebuildable"?
A. Yes. You can order repair kits that include new vanes, bearing and seals to restore your motor to like-new condition (assuming that no
damage has been done to the internal body surfaces of the motor.)
Q. Can I use air motors in an explosive environment?
A. Read carefully! Air motors are often specified as the ideal solution for use in potentially explosive environments. Some of the
advantages of air motors in these environments are: air motors in and of themselves are not a source of electrical spark, they naturally run
cool due to the air expansion that is occurring within the motor and while running they are positively pressurized from within. This does NOT
mean they can be safely used without precaution in any and all explosive environments! It is very important to remember that each application
is unique and there is a very wide range of “explosive environments”. The Gast catalog states the following about Gast air motors:
"Most of the Gast air motors and some of the gearmotors in this catalog meet the requirements of the EC directive
94/9EC (ATEX 100a). They may be used in zones 1 and 2 where explosive atmospheres of gas or dust are likely to
occur. These are marked with [Єx] II 2 G D c T4 in the catalogue and on the product. This indicates the air motor is
Group II, Category 2, Gas and Dust Atmospheres, and a maximum surface temperature of 275OF/ 135OC. Check
that the product driven by the air motor meets ATEX directive. There are several points regarding the safety of air
motors. Our air motors are not a source of electric sparks. However, it is possible that an article which is not part of
the air motor (e.g., wrenches, hammers, etc.) could create a spark by sharply impacting a cast iron or aluminum case
or the steel shaft of the air motor. Note that electric motor enclosures for both class 1 and II hazardous locations can
be made of “...iron, steel, copper, bronze, or aluminum...” (UL 674, Electric Motors and Generators - Hazardous
Locations, June 23, 1989; paragraph 4.2, page 6)].
Gast air motors are designed to be operated by compressed air, the expansion of which creates a cooling effect. As a
result, the outside surface temperature of the air motor will not reach ignition temperature. A maximum surface
temperature of 275OF/135OC Operation of the air motor with compressed air purges a flammable mixture from the
inside of the air motor. To prevent static electricity from being an ignition source electrically ground the metal air
We do not guarantee the safety of any application, but to ensure the safe operation of an air motor in your application,
always follow the product operation manual, follow ATEX 100a when operating in a hazardous atmosphere and
consult with a qualified engineer."
Please note that not all Gast Gearmotors are marked with the "[Єx] II 2 G D c T4" classification.
Q. Can I make an air powered car using one of your air motors?
A. Click on this link to see our answer to this question....