VFD mounting options

Has anyone mounted VFD's at a position other then vertical? I have a panel that is narrow and tall. Instead of having two rows of vertical mounted VFD's, I'm thinking about mounting them horizontally and having one row running vertical. Make any sense? I'm guessing that the cooling capacity will be reduced, but will it be reduced enough to make a difference. VFD's will be AB PF40 2hp flavor, all on DNet. Panel is 18"W x 48" tall x 8" deep. I can have two horizontal rows of three VFD's each or one vertical row of six.

Thoughts?

If they are new drives covered by a warranty, mount them as the manual specifies including proper spacing and minimum clearances.This would seem to be the smart way to go. Be sure to verify the minimum cabinet size to handle the heat load.

http://samplecode.rockwellautomation.com/idc/groups/literature/documents/um/22b-um001_-en-e.pdf

Page 13 of this pdf document states Mount the drive upright on a flat, vertical and level surface. All things aside; that wins for me.

s.f

But, the poster still has a problem. If you mount one VFD over another one, the heat from the lower unit enters the upper unit and the upper unit runs too hot and eventually faults on overtemp. It sounds like his space is such that mounting over/under is the only practical way.

What to do?

My suggestion is to mount over/under but then install a shroud or air dam so that the heat from the lower units can exit the enclosure thru vents half way up the box. Also provide intake vents half way up the box so cool air can enter and pass thru the upper units.

This may not be convenient but is the only practical way to utilize the space and properly cool the drives. Laying them on their side is absolutely unacceptable and will void the warranty.

Ive laid Mitsi E500 drives on their back for some horizontal panels in the past with nary a hint of problems. Done the same for several AutomationDirect drives as well without problem too. Since many drives have fans to pull air across their heatsinks, I don't really understand the issue (provided there is a fan). If the drive has to depend on forced air cooling to not fail, does it matter which way the air enters and leaves? I'd think ambient cabinet temp would be more of a concern with that many drives inside, regardless of their orientations.

-rpoet

its not so much the direction as its focing the warmer air from the previous heatsink into the other VFD a fan can only cool so much

mordred,
If that's the case, I'd guess mounting "sideways" would actually be better, as the fans would not me passing warm air from one heatsink to the next.

-rpoet

lol that wouls work but it would be a bit of a pain with regards to the HMI reading it sideways and all but do-able

You missed a key point in Dick's post:

DickDV said:

Laying them on their side is absolutely unacceptable and will void the warranty.

Click to expand...

You may argue that if appropriate precautions are taken the cooling will be adequate etc. etc. And you are probably right. However, the manufacturer doesn't have any interest in analyzing all details and re-engineering an application just so they will have to cover failures under warranty. So, if you need to do this that's OK, but the liability for premature failure is all yours.

Thanks for the replies. Here are pdf's of the two layout options I'm looking at.

DickDV's suggestion for vents isn't an option because this is a SS panel in a washdown location (although sanitation will try their hardest to water cool the inside of the panel!)

My boss said the same thing that mordred posted, so he's not thrilled with option 2 either.

Any other ideas?

I agree with Tom... if the drive fails premature its your own fault.

I think your only option here is to up size the enclosure. I like to use line reactors with class J fusing which would require more real estate.

You may want to think about a larger enclosure since the drives will heat up the air inside the panel and sounds like there isn't going to be any ventilation.

I agree with your comments Critt. However, upsizing is not in the cards as this is a retrofit project I must use the existing panel. If I had my way I would spec a bigger panel (much bigger). But my boss says that isn't in the budget. There are also machine limitations to a bigger panel as it would block access to/around the machine and equipment nearby.

As far as premature failure from overheating goes.... Long before I can got hired here, it was common practice to use the smallest cabinet possible and cram as much equipment into it as they could. Therefore, we have a lot of SS washdown cabinets packed with VFD's, PLC's, power supplies, and transformers with no cooling options and internal ambient temps that run 100F+ (even higher in summer months). I fully understand that it isn't recommended; and while I personally have had a few VFD's fail for overheating, there haven't been many (usually one every summer the first week it gets into the 90's). I'm not condoning the practice here, and I would like to get away from it; even eliminate it. But in this case, I stuck using what is there.

Patrick

Have you considered buying washdown duty NEMA 4X drives and mounting them outside the box? Several manufacturers make them.

if you have room to mount vertically I would do so however I would also look for means to increase the amount of air exchange within the cabinet. Recognizing that you mentioned a high washdown location. How you exchange the cabinet air will be an issue. Adding several cabinet draw and remove air fans will definetely help here Unfortunately your wiring is probably coming out from the bottom of the box. So I would add exchange fans to the sides of the cabinet. have a set drawing cool air in and a set removing the hot air. I would also recommend recording the amount of heat increase the cabinet gets when the door is closed. One way you can prevent the hot air from the one unit entering the other unit is to place a deflector between the drives. However you still need to exchange that air.

One other suggestion on the warrenty issue with the AB drives you can get a Rockwell drive specialist to come in and work out a solution with you this way if you get their signature that all is good for the installation you get the warrenty protection. With this signature the warrenty is also much easier to qualify for. I would suggest getting a local rep to come in and provide suggestions on mounting for your room considerations.