# motor whineing sound, with VFD / Bad or what?



## rogee (Jun 20, 2013)

I finally have my Hardinge TM up and running on a TEMco VHD. supper neat, but am getting a strong whining noise from the motor. I remember seeing this covered in several previous posts but can't find them now, should I be worried about this?
I remember someone saying you could take this out by adjusting the switching speed ,or something, but again can't find that post. Any suggestions or advise appreciated.


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## jgedde (Jun 20, 2013)

rogee said:


> I finally have my Hardinge TM up and running on a TEMco VHD. supper neat, but am getting a strong whining noise from the motor. I remember seeing this covered in several previous posts but can't find them now, should I be worried about this?
> I remember someone saying you could take this out by adjusting the switching speed ,or something, but again can't find that post. Any suggestions or advise appreciated.



That's exactly right. You need to raise the switching speed so that the motor doesn't make noise. This is also known as the PWM frequency. You really want to run the switching speed as low as you can without having noise issues because the VFD's efficiency goes down (runs hotter) with increasing frequency (as switching losses become greater) and RF interference can increase. 

In some cases, the switching frequency excites the motor acoustically and then they're really noisy. Usually raising the frequency (or even lowering it) will help here.

Your VFD manual will tell you how to set the switching frequency. I'll look it up if you tell me the VFD model number you have but it looks like P297 is the parameter you need to adjust.

John


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## itsme_Bernie (Jun 20, 2013)

John nailed it.

I have a Hardinge TM as well, so congrats!!  I LOVE mine.

I had the same squealing issue recently, but not with the TM.  That motor only lightly squeals.  Is it a TECO VFD?  That is what i have.  That frequency adjustment made a big difference.  I think it was function # 40, or 43 or something.

Make sure NOT to switch those tempting motor switch arms while the motor is still turning!  Bad for VFD, in case you didn't know....

Bernie


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## rogee (Jun 21, 2013)

John,

The unit I have is a TEMco CFW10, model # C10014. 

Thanks
Bob

- - - Updated - - -

Bernie,

Thanks for the tip on the control arms. I was worried  that someone might move those arms, so I wired the VFD directly to the motor, going around all of the controls that came with the machine.

Bob


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## jgedde (Jun 21, 2013)

It is P297 you need to tweak...




John


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## rogee (Jun 22, 2013)

As so often happens to me when reading technical info on this site, I actually become more confused as I read.  I find that the Squealing sound is bad for the motor, but can be corrected by increasing the switching speed, which will cause the motor to over heat, and eventually destroy the motor?? So why increase the switching speed if the end result is the same?

Bob


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## rdhem2 (Aug 21, 2013)

Usually the whining noise is just an annoying thing to listen to.  But as suggested you can possibly make a difference by LOWERING the PWF setting.  Won't cost anything but your time to find out.


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