Multi-Vane Air Motor Occasionally Won't Start
Multi-Vane Air Motor Occasionally Won't Start
(OP)
Hi All
I need some outside expertise diagnosing an odd issue. We have designed a tool that uses a multi-vane compressed air motor. (http://www .irtechpub s.com/ir_p dfs/Air%20 Motors/Air %20Motors/ Vane%20Mot ors/045627 16_ed3.pdf)
We have started this motor hundreds of times, but twice this year (with two different motors), the motor failed to start when we pressurized the inlet (under little load). Both times, air could be seen to be blowing out the muffler, so presumably the vanes were being bypassed, and both times the motor was able to restart after we manually rotated the shaft a little.
Unfortunately our tool may not be accessible during startup, and the risk of failure to start is worrisome. Is this common to this type of motor, and if not, should I be specifying another option or type?
I need some outside expertise diagnosing an odd issue. We have designed a tool that uses a multi-vane compressed air motor. (http://www
We have started this motor hundreds of times, but twice this year (with two different motors), the motor failed to start when we pressurized the inlet (under little load). Both times, air could be seen to be blowing out the muffler, so presumably the vanes were being bypassed, and both times the motor was able to restart after we manually rotated the shaft a little.
Unfortunately our tool may not be accessible during startup, and the risk of failure to start is worrisome. Is this common to this type of motor, and if not, should I be specifying another option or type?





RE: Multi-Vane Air Motor Occasionally Won't Start
Preventive measures that work long enough to say they work, and not long enough to make the motor reliable, include:
- carbon vanes
- vanes coated with dry nonstick lubricating material
- lubrication, applied internally or externally, or atomized in the air
- springs pushing the vanes out
- intentionally coarse finishes on the vanes or the rotor in the hope that air will get into the cavity at the vane root
and probably some other features that I haven't noticed.
For metal vanes in a metal rotor, the best I've been able to do is an occasional drop of Marvel Mystery Oil in the air supply. ... and that still doesn't always work.
Mike Halloran
Pembroke Pines, FL, USA
RE: Multi-Vane Air Motor Occasionally Won't Start
My air supply is furnished with a filter/lubricator, so I'm not sure I can do any more that way. Maybe I should look for a vane motor with springs. Do you know of any in the 1 HP range?
RE: Multi-Vane Air Motor Occasionally Won't Start
I don't know if any motors with spring vanes are available in that size.
Can you arrange for the motor to be cycled regularly so that it stays lubricated and the lube doesn't get a chance to gum up?
Mike Halloran
Pembroke Pines, FL, USA
RE: Multi-Vane Air Motor Occasionally Won't Start
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They show spring-loaded vane in their MR-series motor. 61MR, 1 hp.
Ted
RE: Multi-Vane Air Motor Occasionally Won't Start
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Ted
RE: Multi-Vane Air Motor Occasionally Won't Start
RE: Multi-Vane Air Motor Occasionally Won't Start
I had some issues with the veins rusting or sticking on some air motors for me recently.
What if..
There was a valve on the exhaust side, and you just close the valve when the motor isn't running. On the inlet side, I'm using there's some FRL system there, so it'll keep that side dry too..
Or perhaps, setting the regulator to 1-2 psi, so that the inside of the motor/veins were always under positive pressure.
RE: Multi-Vane Air Motor Occasionally Won't Start
My current plan is to go with the Deprag "advanced line" motors which include vane springs. (These are more expensive, and they might introduce their own problems down the road with fatigue - we'll see).
RE: Multi-Vane Air Motor Occasionally Won't Start
Ted
RE: Multi-Vane Air Motor Occasionally Won't Start
We looked at this. The vanes are so light, and the surface area between the vanes and their slots is so large that the shear force from the lubricant is more than enough to keep the vanes from falling out under their own weight, even when shaking vigorously. It wouldn't matter what orientation the cylinder was in with respect to gravity - the vanes tend to stay bottomed out after they pass the narrow part of the cylinder unless pushed out by air pressure, springs or centrifugal force.
(Plus, in our motor, the cylinder is assembled inside the motor body without any kind of angular locating feature, so we can't know which orientation the eccentric is in).