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Thread: 3 Phase motor noise?

  1. #11
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    Quote Originally Posted by MattiJ View Post
    You need to be pretty old or deaf not to hear 12khz whine. At 40 my hearing sensitivity seems to fall off at around 15khz.
    And I have like worst hearing amongst my friends. I remember when I was in twenties the CRT television line frequency whine @ 15.6khz was audible just barely when some of my friends were going nuts with the whine.
    Aviation hasn't been kind to my hearing

    Sent from my SM-G950U1 using Tapatalk

  2. #12
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    Quote Originally Posted by RB211 View Post
    Aviation hasn't been kind to my hearing

    Sent from my SM-G950U1 using Tapatalk
    Yeah, I was about to mention something about that those turbojets/fans/props might have something to do with it in your occupation.

  3. #13
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    I don't hear the whine either but I sure hear the gravel in the chain drive! What the heck is that?

  4. #14
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    Feb 2019
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    Wisconsin
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    I think you are hearing a rattle that is in the coupling going to the power draw bar, I have to look at that yet. Its belt drive variable speed.

  5. #15
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    Quote Originally Posted by Mopar_Mudder View Post
    I did check the specs on my VFD and it has no derating for the higher frequency, it will go up to 15.0. Also just wanted to make clear the VFD make no noise it is just the motor.
    Not the VFD... the motor is affected by the higher carrier frequency. Goggle is your friend.

  6. #16
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    Quote Originally Posted by MattiJ View Post
    Yeah, I was about to mention something about that those turbojets/fans/props might have something to do with it in your occupation.
    At 66 (nearly) mine is shot in the 5-8K range, then dies off at 12k to nothing. Shrill women still get my Attention.

  7. #17
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    Nov 2008
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    Quote Originally Posted by MattiJ View Post
    You need to be pretty old or deaf not to hear 12khz whine. At 40 my hearing sensitivity seems to fall off at around 15khz.

    My inverter rated motor had a wicked whine when I first set it up. I thought the bearings were bad. I changed the frequency and it went away. I found that it was dead quiet when I went back to the original value and changed it just 10% or so. In my case the problem appeared to be a resonance within the motor.

    Dan
    At the end of the project, there is a profound difference between spare parts and extra parts.

  8. #18
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    Jul 2014
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    Southern Indiana
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    MoparMudder: Is this a used machine? To me, it sounds like worn stuff in the variable drive. Try changing the spindle speed while it s running. Changing the spindle speed while running from the slowest speed to the highest speed, may show areas where there is no or very little rattle.

    Sarge41

  9. #19
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    I didn't mean anything by my comment. Noisy machines are often referred to as "rock crushers", "chain drive" or "thrashing machines". That video ranks right up there with the best of them. I hope it's just your drawbar rattling around in there but if it is, it may be bent or missing a washer. That sound is not normal

  10. #20
    Join Date
    Feb 2019
    Location
    Wisconsin
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    Thanks for the feed back, I really don't know what it should sound like being my first mill.

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