VFD Mounting Clearence in an industrial enclosure

[dpslusser]

Hello All,

I have a question regarding VFD mounting in an enclosure.

I have a VFD that requires 3.25 inches of clearance around the top, bottom, left and right side of it anytime it is placed against walls or another VFD.

My question is in regards to wireway placed by the VFD's. If a VFD has a depth of 12 inches but the wireway only has a depth of 3 inches. Does the same clearance criteria need to be followed? And also being that wireway is basically "vented," and not a solid object.

I tried looking up a whitepaper on the subject from a couple of VFD manufactures, but cant' seem to find anything helpful. Plus a few google searches.

I wanted to see what you guys thought.

Thanks,
Dave

 

[Besoeker]

We routinely put VSDs in enclosures.
The VSDs dissipate heat
We ventilate the enclosures.
I just work out what airflow is required and we fit fans and filters to accommodate that.

 

[dpslusser]

I did a heat calc on the enclosure and added 2 water cooled heat exchangers.

But room is still premium and would like to disregard the wireway as a solid object when it comes to clearences of the drive. The wire way doesn't even block the fan's of the VFD's. Thats what making me question the need.

 

[Besoeker]

I did a heat calc on the enclosure and added 2 water cooled heat exchangers.

But room is still premium and would like to disregard the wireway as a solid object when it comes to clearences of the drive. The wire way doesn't even block the fan's of the VFD's. Thats what making me question the need.

What sort of drive ratings are they and why do you need heat exchangers?

 

[Jraef]

Hello All,

I have a question regarding VFD mounting in an enclosure.

I have a VFD that requires 3.25 inches of clearance around the top, bottom, left and right side of it anytime it is placed against walls or another VFD.

My question is in regards to wireway placed by the VFD's. If a VFD has a depth of 12 inches but the wireway only has a depth of 3 inches. Does the same clearance criteria need to be followed? And also being that wireway is basically "vented," and not a solid object.

I tried looking up a whitepaper on the subject from a couple of VFD manufactures, but cant' seem to find anything helpful. Plus a few google searches.

I wanted to see what you guys thought.

Thanks,
Dave

No drive manufacturer is going to stick their neck out to try to cover ALL of the intricate little "what if" variations on the theme of something like clearance. It either is, or it isn't within 3-1/2 inches as far as anything they are going to say. It's not just about "venting" either, it's about clear FLOW of air without obstruction. An eddy or swirl of air can leave a single component on a PC board unable to get rid of it's heat fast enough, despite the ambient air. I just had a situation where small little capacitors were failing repeatedly on a PC board for a bunch of 1HP drives. Turns out the way the drives were installed was creating an air pocket swirl that prevented air flow across the board and let the caps over heat, even though the enclosure has air conditioning set to 80F (well below the 40C rating of the drives). I put temperature indicator stickers inside of the enclosure and others under the cover next to the PC board. None of the indicators in the general area inside turned color above 90F (probably because of opening the door in the summer), nor did the ones in other areas inside of the drive. But right on top of the PC board, 138F, almost 50C, just because of a swirl. Caused, by the way, most likely by the wire duct placement.

So basically, you can take your chances but be prepared for the consequences.

 

[dpslusser]

But right on top of the PC board, 138F, almost 50C, just because of a swirl. Caused, by the way, most likely by the wire duct placement.

Wow,

I never thought of something like that happening. Thanks for the enlightenment . I know in the past when we have had some bigger (expensive) drives fail, some of the first questions we get asked from the vendor is the clearences around the drive and heat calcs. So we always cover our butts by sticking to manufacture recommendations.

I just wanted to see if anyone had any insight to mounting wireway close to VFD's.

-Dave