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pneumatic thermostat compressor

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Grallert
Grallert Member Posts: 660
Hi everyone. I have a motor question. My system is controls are pneumatic operated with two compressors. One of the motors is making me nervous. I'm by no means fully up to date on all the different motors and their uses but this one doesn't seem right.

The motor on our other compressor seems like it will run for ever.
Would someone direct me to the correct motor? I suppose I could get a duplicate the functioning motor and have the three phase reconnected.
Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker

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  • bob_46
    bob_46 Member Posts: 813
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    Looks like someone trying to save a buck. The motor you have on there is split phase, no starting torque. Do you still have the magnetic motor starter for the three phase motor?

    There was an error rendering this rich post.

  • Grallert
    Grallert Member Posts: 660
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    You know it could be here in the accumulated history of this institution.
    I'm not sure if this was an attempt to save a buck or if it was a quick fix that's lasted how ever long. Now that this place is mine to care for it's time to straighten out all these "fixes".
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • ratio
    ratio Member Posts: 3,653
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    Verify the controls are appropriate for a 3 phase motor (& complete/in working condition), then get a spare motor on hand. No need to swap it out 'til the old one fails. There's bound to be other patches that are in more need of correction than this one.
    Grallert
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,624
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    In the past most "engineers" would specify 3 phase motors on anything 1/2hp and larger. 3 phase is more efficient and the motors last longer in my opinion.

    Just like steam systems everyone wants to rip pneumatic controls out. All they need is a little fine tuning and calibration and they will work and last a long time.

    It's important to drain moisture out of the air tank either manually or with a auto drainer. If the compressor is worn oil can get in the system which is bad for the controls.

    try and get a handle on any pneumatic leaks to minimize compressor run time.

    see if you can find the belt guard for that motor

    that's a start.

    Check out "National Energy Controls Corp" for parts and assistance
  • Grallert
    Grallert Member Posts: 660
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    Thanks for the replies guys. I've slowly tracking down the air leaks in both of my pneumatic systems here. Slow going. I'll have the 3 phase reinstalled for this compressor.
    Thanks for the tip on National Energy Corp I'll check them out.
    I'm constantly surprised by some of the "fixes" I find here on campus. Work arounds that are way more complicated than the system being serviced.
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,239
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    That motor won't last. It's a fan motor. No starting torque and depends on the fan it is turning for cooling.

    If you want to stay single phase, go farm duty or general purpose.

    3 phase is the best. And if you go 3 phase, you can slap a drive on it and operate the compressor at the lowest rpm the provides sufficient cfm. It will make the compressor last longer. Wear on rotating machinery increases to the square of speed. If you do go with the drive, choose an inverter duty motor.
    Grallert
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,624
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    I guess if the compressor is splash lubricated you could put a drive on it. Not sure about some other compressors like a Quincy which has an oil pump.

    I didn't see the pictures yesterday as they didn't load for some reason. @Harvey Ramer is correct that isn't the best motor for the job to be sure. If it was three phase originally stay with that.

    Pneumatics can be reliable and reasonably accurate if you know how to work on it. The ones that don't want to rip it out
  • Grallert
    Grallert Member Posts: 660
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    I'm going to have the three phase reconnected it seems the way to go.
    Unfortunately or fortunatley I have to teach myself how to work on this air system so the learning curve is slowed down.
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,624
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    snif around for some old pneumatic books. weather the system is Honeywell, Powers, Johnson, Barber Colemen what was the other one ...Kreuter they are all the same. Not hard to learn the basics.

    I am sure NECC ha s some info
  • JUGHNE
    JUGHNE Member Posts: 11,076
    edited March 2017
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    If you could find "Fundamentals of Pneumatic Controls" by Robertshaw Uni-line. I picked this and others up at a trade show in the late 70's......don't know why as I had never seen a pneumatic control in my life, but good thing I did. Now have a small Powers system to take care of dating from 1961.
  • Grallert
    Grallert Member Posts: 660
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    Thanks for all the input folks. I do have the original books with all of the controls used but they're only so helpful in diagnosing all the little issues.
    Looks like a will need to get a testing kit. New tools :D
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker