Noise levels in VFD motors 2

[edison123]

Recently, I saw 2 VFD driven 1000 HP motors running with a howling noise.

Is there any standard for the noise levels specifically for VFD driven motors ?

What is the accepted noise level ?

 

[Skogsgurra]

Yes, there are standards. At least in Europe. Something like 85 dBa at 1 m. 1000 HP and howling - I think I know what make.

There were older VFDs with GTOs that were running at low carrier frequencies. They often had resonances in things like connection box cover and other parts. Acoustic foam inside helped a lot.

There is also a new generation with IGBTs where switching frequency has been taken down to 1.6 kHz and thereabout to reduce switching losses, bearing damage and EMI. They also howl. Foam sometimes helps here, too.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[edison123]

Thanks Gunnar.

These were ID fan motors and no doubt the ducting play a part.

Could tell me the european std no. ?

Most of the industrial equipments are supposed work under 70 dB. Is there an exemption for VFD motors ?

 

[Skogsgurra]

Not sure, will search my heaps...

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[Skogsgurra]

No. I will NOT search my heaps. They started tumbling down over me. But I found this

http://www.reliance.com/mtr/pcnomn.htm

There is much more, but the Reliance site is a good start.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[edison123]

Thanks Gunnar, it was very informative.

 

[jraef]

Gunnar searching in his heaps...

 

[edison123]

Sorry Gunnar, if I made you do this.