# Just had an emergency service call at the shrimp plant...



## erics37 (May 7, 2009)

Turned out that their R2 unit had a bad motivator :blink:










Naw actually,

They spent a bunch of money last year on upgrading their shrimp processing facility to meet more stringent requirements for the European market. They've got a clean room with a big control cabinet containing their PLC, a couple drives, and various auxiliary devices. Couple of issues:

First, the reason they called me on a Saturday morning was because their PLC wasn't getting any power. I ran down there and it turned out that it was supplied through a fancy Allen Bradley surge protector of some sort, and it had taken a surge and was no longer supplying power. It sacrificed itself but it protected the PLC. They had no replacement on hand and the line was full of shrimp waiting to be processed, so I bypassed the device and got the PLC back online. They rush ordered a new surge protector and a spare.

Now when I was in the cabinet, which is a 4X enclosure, I noticed telltale signs of corrosion beginning to form on most of the device terminals and so forth. Their was a fair amount of moisture in there too, not big drops of condensation, but a fine wet layer on most surfaces. I thought about the possibility of putting a cabinet heater in there, but what about when they've got all the drives running at the same time? I guess a thermostat could kick the heater off if the drives were keeping it warm in there.

There was also a layer of weird dust on everything. It wasn't normal dust, it was white and kind of powdery. I'm wondering if it was crushed up shrimp shell dust or something. Either way, it's fine enough to get through the vent filters. Anything I can do about that?


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## John Valdes (May 17, 2007)

I would install an AC. This will cool and keep dry the inside of the enclosure.


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## erics37 (May 7, 2009)

John Valdes said:


> I would install an AC. This will cool and keep dry the inside of the enclosure.


Any pointers to some specific units?


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## MollyHatchet29 (Jan 24, 2012)

An R5-D4 or E-3PO would probably do the trick. Even though the battle droids look much cooler.


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## micromind (Aug 11, 2007)

A cabinet-mount A/C unit will keep the VFDs cool plus it will de-humidify the inside of the cabinet. 

They're easy to install, just cut a couple of holes in the side of the cabinet and bolt it on. 

Sort of a distant memory, but I think they were made by a company named Thermal Edge or Thermal Devices or something like that.


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## erics37 (May 7, 2009)

micromind said:


> A cabinet-mount A/C unit will keep the VFDs cool plus it will de-humidify the inside of the cabinet.
> 
> They're easy to install, just cut a couple of holes in the side of the cabinet and bolt it on.
> 
> Sort of a distant memory, but I think they were made by a company named Thermal Edge or Thermal Devices or something like that.


Well I googled it; there is both a Thermal Devices *and* a Thermal Edge :laughing: Looks like Thermal Edge had the edge:

http://www.thermal-edge.com/aircon/series.aspx#cs

Thanks for the lead :thumbsup:


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## WIElectric (Feb 21, 2012)

Can you get a HEPA vent filter? That would filter out your white mystery dust.


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## Big John (May 23, 2010)

WIElectric said:


> Can you get a HEPA vent filter? That would filter out your white mystery dust.


 I was thinking it. But I think the better solution is the air-conditioner: Just seal the cabinet as best as possible and let the AC do the work. That solves all 3 problems: Condensation, dust, and heat.

-John


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## 347sparky (May 14, 2012)

Maybe put duct seal in the conduits to stop any humid air from entering the cabinet from other areas.


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## Vintage Sounds (Oct 23, 2009)

Hammond makes cabinet air conditioners too. 

http://www.hammfg.com/electrical/products/climate


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## backstay (Feb 3, 2011)

Your dust might be mold.


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## JRaef (Mar 23, 2009)

If you have vents, it is not NEMA 4! Vents cannot exclude moisture. I run across this a lot with cabinets that have drives in them, people think just because the box is stainless steel, it is somehow magically telling the moisture to stay away! If you have to exchange air, you will exchange moisture.

Install an AC unit and seal up the box or move the whole thing to an air conditioned room that will have low airborne moisture. Otherwise they are headed for failure.


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## ampman (Apr 2, 2009)

KLovelace29 said:


> An R5-D4 or E-3PO would probably do the trick. Even though the battle droids look much cooler.


are you still partying


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## tates1882 (Sep 3, 2010)

erics37 said:


> Turned out that their R2 unit had a bad motivator :blink:
> 
> 
> 
> ...


The fine white dust is actually minerals left behind from the condensation evaporating. Defiantly need to condition the cabinet.


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## Big John (May 23, 2010)

JRaef said:


> If you have vents, it is not NEMA 4! Vents cannot exclude moisture....


 I gotta see if I can find the part number, but I seem to remember we were putting in listed NEMA 4 vents on cabinets when I did pharmaceutical, they were big cylindrical contraptions. But I agree, the standard louver vent voids the listing.

-John


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## user4818 (Jan 15, 2009)

Too many words. Didn't read.


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## JRaef (Mar 23, 2009)

NEMA / UL type 4 test criteria; hose directed water at 100GPM from ANY angle. That equates to about 60 PSI from a 1" nozzle. Aim that at your NEMA 4 vent and see if it leaks.

One of the problems is the use of "NEMA 4" vs "UL type 4". NEMA was never enforced, it was a set of "industry design guidelines", but nobody tested anything except the manufacturer. Now they have been adopted by UL, who actually does testing and listing. So some people get away with things like calling their vent kits "NEMA 4" then get them UL listed as type 12, which is all they can pass, but they know that most people will not catch the semantics issue. But a UL508 panel shop will get burned if UL sees it in their file. I know.....:whistling2:


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## Big John (May 23, 2010)

JRaef said:


> ...So some people get away with things like calling their vent kits "NEMA 4" then get them UL listed as type 12....


You mean to say that even though the packaging says "NEMA 4" they're actually listed as NEMA 12? That seems pretty shady.

-John


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## John Valdes (May 17, 2007)

erics37 said:


> Any pointers to some specific units?


Start here. http://www.hoffmanonline.com/produc...t_1=34&cat_2=2383&SelectCatID=2383&CatID=2383

Or call Shaefer Enclosures and see what they have to offer as far as air quality equipment.


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## erics37 (May 7, 2009)

Wow, I just got a callback from the shrimp plant, I was there for the last 2 or 3 hours.

So yesterday, of course, I went down and found the blown surge protector and got them back up and running. Well once I got the PLC back online and everything checked out, I packed up my s**t and left.

The maintenance guy said he would go ahead and clean up and get everything all back in order. Well it turns out that he didn't close all the latches on the PLC cabinet door, so when the workers did their washdown a ton of water dribbled into the cabinet :blink: They finally noticed something was wrong when motors started shutting off and smoke came out of the cabinet.

I found the whole terminal strip block on the bottom was saturated with water and a few of the terminal blocks had burned through to each other, and there was a row of 4 MMPs that were ruined as well. They had enough spare parts sitting around to ghetto rig some more MMPs until the proper replacements can show up, and for the terminal block I just wire nutted everything together.

NEMA 4 or 12 or 3R or whatever is irrelevant if you leave the panel door open :laughing:


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## Splash (Apr 11, 2008)

erics37 said:


> NEMA 4 or 12 or 3R or whatever is irrelevant if you leave the panel door open :laughing:



You have no idea how many Nema 7/9 explosion proof starters we opened that were full of water down in gas plants after hurricane Rita.


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## erics37 (May 7, 2009)

Splash said:


> You have no idea how many Nema 7/9 explosion proof starters we opened that were full of water down in gas plants after hurricane Rita.


I can imagine.


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## JRaef (Mar 23, 2009)

erics37 said:


> ...The maintenance guy said he would go ahead and clean up and get everything all back in order. Well it turns out that he didn't close all the latches on the PLC cabinet door, so when the workers did their washdown a ton of water dribbled into the cabinet :blink: They finally noticed something was wrong when motors started shutting off and smoke came out of the cabinet.
> ...


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## John Valdes (May 17, 2007)

That's right. Sounds like the perfect instance where the control panel should be located remotely from the process. I would move it.
Your facility would have been a great customer when I was in this motor and control business. We loved this type of environment for the apparent reasons.
What type of "Wash-down" motors are you guys using? 
You do know NEMA 12 is only dust resistant?


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## JRaef (Mar 23, 2009)

I had built a crusher control system once, a lot of separate control panels with soft starters and across-the-line starters, each in it's own cabinet because they moved equipment around to change configurations often. I got a call one day complaining that all of our contactors were rusted and sticking! We had used ABB contactors and although not the best, they certainly are better than that. Flew from Seattle to Palm Springs on a Sunday, drove out into the desert for hours and get to the job site. Sure enough, every contactor is rusted on the INSIDE, no evidence on the outside. I start replacing contactors, and a flunky drives by, stops the car and says "Oh, I see they are finally getting someone to replace those contactors we wrecked". I asked him what happened, he said that they had all of the doors open for some sort of inspection, and a water truck drove by an spayed them all with a heavy dousing! They had cleaned them all up with towels, but apparently nobody though to disassemble the contactors and clean them up on the inside. 

Cha-Ching! $$$

Amazingly none of the soft starters were damaged, but nothing was energized when it happened either, so that is probably what saved them. The PC boards must have dried out before anything bad happened to them. There was some rust on the mounting srews inside though.

When I sent them the bill and they complained, I told them that my warranty did not cover water truck spray damage. The guy was furious and demanded to know who told me that. Luckily I never asked the guy his name so I was not going to be responsible for getting the guy fired, but I did get my check, and it was a princely sum I might add.


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## erics37 (May 7, 2009)

John Valdes said:


> That's right. Sounds like the perfect instance where the control panel should be located remotely from the process. I would move it.
> Your facility would have been a great customer when I was in this motor and control business. We loved this type of environment for the apparent reasons.
> What type of "Wash-down" motors are you guys using?
> You do know NEMA 12 is only dust resistant?


The machine is all one big pre-assembled unit. It was manufactured in Iceland or someplace like that and shipped over in a couple of pieces. The PLC cabinet is right in the midst of it all, nuttin' we can do about that.


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## toklover (May 7, 2012)

http://www.rittal-corp.com/index.cfm
As a onestop shop, Rittal has some pretty neat gear, they have temp & humidty sensors, they do an assortment of panel fans, and they do vortex cooling as well, which is ideal for Nema4 environments.

It sounds pretty r3tard3d the way they've laid out the panel, I mean, for a food manufacturing environment, you would have thought, isolate the expensive thing that makes us money in a relatively safe place & have remote control panels for any HMI needs

Nows a good chance to sell them a preventative measure, some limit swicthes on the door, wired to some strobes & sirens, let people know when the door is open, a cooling/heating system to extend operational life of their panel.


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## Jlarson (Jun 28, 2009)

I've had good results with these corrosion inhibitor things 










From USA Blue Book http://www.usabluebook.com/p-270994-corrosion-control-emitter-11-cu-ft-with-adhesive-back.aspx

The spray they sell works pretty good too.


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