# Protect control cabinets from problematic power sources



## scotch (Oct 17, 2013)

ICM makes a 3ph line voltage monitor that would work for your application as well ....we used them on large heat pump compressors.


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## MikeFL (Apr 16, 2016)

Welcome to the forums.

Just curious: Do you drink beer?


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## BeerMaintenance (Apr 2, 2019)

MikeFL said:


> Welcome to the forums.
> 
> Just curious: Do you drink beer?



not enough information. On or Off the job?


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## BeerMaintenance (Apr 2, 2019)

scotch said:


> ICM makes a 3ph line voltage monitor that would work for your application as well ....we used them on large heat pump compressors.



I see many brands that make them. Is there a reason ICM is better than others? Honestly leaning toward ABB right now, but they have so many models I am not sure which is best for my application. 



I think in any case it's going to be a tough call between sensitivity/protection and reliability/no false trips.


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## MikeFL (Apr 16, 2016)

Well I was curious if you're around it all day, is that really what you want when you're not at work. 

Friend of mine was graveyard shift manager of a large beer distributor on the east coast. We used to get unlimited beer for $5/ case, any kind we wanted. We didn't do it all the time, but if we were going fishing or having a party, we could always count on him for at least part of the day's needs being met.


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## BeerMaintenance (Apr 2, 2019)

Theres always cans/bottles that the machines reject for various reasons... 1mm too low filled, or damaged lables... employees get to fight over those  They also sell to us at cost


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## Rora (Jan 31, 2017)

Not sure about the equipment, but since you're tasked with this just understand that you're now the fall guy whether you tune it "on the safe side" and it shuts down production for a nuisance alarm, or tune it for practical reliability then anything fails which might point the finger at the supply.

Be sure to keep management involved, give your defense on the small details up front and get them to sign off on it... ultimately make sure that you're just providing the legwork for a solution, not being responsible for it.


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## MikeFL (Apr 16, 2016)

Rora said:


> Not sure about the equipment, but since you're tasked with this just understand that you're now the fall guy whether you tune it "on the safe side" and it shuts down production for a nuisance alarm, or tune it for practical reliability then anything fails which might point the finger at the supply.
> 
> Be sure to keep management involved, give your defense on the small details up front and get them to sign off on it... ultimately make sure that you're just providing the legwork for a solution, not being responsible for it.


That's outstanding advice.

Another option is to tell them what their options are and let them select what protections they want.


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## joebanana (Dec 21, 2010)

BeerMaintenance said:


> I see many brands that make them. Is there a reason ICM is better than others? Honestly leaning toward ABB right now, but they have so many models I am not sure which is best for my application.
> 
> 
> 
> I think in any case it's going to be a tough call between sensitivity/protection and reliability/no false trips.


Do they have a sales rep.? Maybe contact him/her, and ask. Share the blame.


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## Rora (Jan 31, 2017)

MikeFL said:


> That's outstanding advice.
> 
> Another option is to tell them what their options are and let them select what protections they want.


Even better... this also transfers the responsibility of asking the right questions onto them. If you just spec something out that they then approve, they can still claim "you didn't tell us that, it was your idea and I trusted that you made the right choice!"

They ought to vett everything you present either way, but by making it their decision puts the onus on them to make sure THEIR decision is a good one. You might still get some flak if something happens but you're a lot less likely to get fired as a scape goat.


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## gpop (May 14, 2018)

I honestly do not see the point. In real life equipment is damaged by the spike with in 1 cycle so trying to disconnect the equipment just seems to slow. 

A simple phase/voltage monitoring relay should be able to shut down control power which covers some of the problems (brown outs), Ups units on the control power protect the expensive parts then a box full of surge suppressors deals with the spikes. 

In florida i swear more panel space is used for suppressors and ups units than plc hardware.


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## BeerMaintenance (Apr 2, 2019)

MikeFL said:


> That's outstanding advice.
> 
> Another option is to tell them what their options are and let them select what protections they want.



This is what I normally do. 



I'm not worried about being 'held responsible' in the way that you guys are thinking. I don't get grief for trying... they just want solutions that generally make things better. 



Speaking of filtering, do the line filters do a whole lot? I have seen them factory installed for higher end machines, like Kuka robot cabinets... but they aren't much more than RC filter circuits, correct? I could see them help with electrical noise, but I don't have that problem.


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## BeerMaintenance (Apr 2, 2019)

gpop said:


> I honestly do not see the point. In real life equipment is damaged by the spike with in 1 cycle so trying to disconnect the equipment just seems to slow.
> 
> A simple phase/voltage monitoring relay should be able to shut down control power which covers some of the problems (brown outs), Ups units on the control power protect the expensive parts then a box full of surge suppressors deals with the spikes.
> 
> In florida i swear more panel space is used for suppressors and ups units than plc hardware.



This is why I am asking. I understand a phase monitor won't prevent all problems, but the vast majority of the damage I have seen has been the on/off/on/brown/off/on cycles that happen during a power failure. If the power just cuts out, that usually doesn't hurt anything, but usually it cycles a few times then quits. 



In my experience with Mov's, they don't last that long, and questionable how much they actually help. Anyone have more experience with them?


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## Bird dog (Oct 27, 2015)

BeerMaintenance said:


> This is why I am asking. I understand a phase monitor won't prevent all problems, but the vast majority of the damage I have seen has been the on/off/on/brown/off/on cycles that happen during a power failure. If the power just cuts out, that usually doesn't hurt anything, but usually it cycles a few times then quits.
> 
> 
> 
> In my experience with Mov's, they don't last that long, and questionable how much they actually help. Anyone have more experience with them?


Maybe a problem with the POCO equipment?


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## glen1971 (Oct 10, 2012)

Depends what is common in your area too.. I've installed lots of Omron K8AB relays for phase loss/reversal with good success.. Tie their dry contacts into a relay/contactor to drop out the control power you want to isolate or alarm, light, etc. They can be time and voltage adjusted on site.

They don't like harmonics though! Found that out after the magic smoke got let out of one.


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## gpop (May 14, 2018)

BeerMaintenance said:


> This is why I am asking. I understand a phase monitor won't prevent all problems, but the vast majority of the damage I have seen has been the on/off/on/brown/off/on cycles that happen during a power failure. If the power just cuts out, that usually doesn't hurt anything, but usually it cycles a few times then quits.
> 
> 
> 
> In my experience with Mov's, they don't last that long, and questionable how much they actually help. Anyone have more experience with them?


Mov's work but by the nature of there design they will fail. You have to work out if the mov failing is cheaper than replacing the hardware it is protecting. 
(works great on the 480v side)

As for the problem you are describing i would go with a phase/voltage protection relay and install it in the control voltage circuit. If you use another relay and a button you can make a simple latched relay for control power.

Operator presses button to turn on control power, Any glitch will cut control power until the button is pressed again (this allows the operator to make the machine safe before restoring power)


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## splatz (May 23, 2015)

BeerMaintenance said:


> In my experience with Mov's, they don't last that long, and questionable how much they actually help. Anyone have more experience with them?


Everyone that uses plug in surge strips has experience with MOVs. As @gpop said, MOVs are sacrificial devices, you have to keep replacing them. Sometimes they sacrifice themselves in spectacular manner blowing apart the SPD. But they don't sound like a good fit for you. 

MOVs don't start acting until the voltage is much higher than the normal supply voltage. If you buy MOV protection for 480V supply it doesn't jump in at 481V. If you have a distribution line or MV line short to your 480V supply they will jump in. They do nothing at all for brownouts, dropouts, etc. Power conditioners do that. 

I know they make big power conditioners but I've only seen them in literature. I have used little power conditioners and a lot of people really swear by them. 
The product brochures claim the big ones are used in medical facilities and telecom, I could see them at say an MRI clinic. They might make sense in an industrial application if the cost of the equipment wrecked and the cost of the lost production justifies it. 

I am not sure what power conditioners do if you lose a phase for more than a cycle or a few cycles. If you can safely cut power (IF) I think something like the macromatic you selected is a good way to go no matter what, if you can install conditioners ahead of the equipment too, they'll have to act less often.


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## JRaef (Mar 23, 2009)

IMHO you can't start throwing money at it until you have fully identified the nature of the problems first. There are solutions for most problems, but not many that will cover more than one. You can't cover every single contingency, it would cost way more than you might imagine, but you can cover most of them if you plan it wisely. I suggest renting or borrowing a recording meter / analyzer for a few weeks first to see what the most common issues are and start with those. 

On a side note: Opening a contactor ahead of a machine every time there is a glitch will only serve the purpose of letting you know how MANY glitches in power take place every day, because it will be a serious annoyance and likely end up disabled in no time. It's better to accept the fact that "stuff" happens and plan for it accordingly.


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## BeerMaintenance (Apr 2, 2019)

Thanks everyone for the input. It's all about what I expected. 



I don't see it as "throwing money at it" when I am only talking about $500 worth of parts to protect a $50k cabinet. 



I also know that some of the cabinets do have 'power conditioners' built into them, but they are small and passive... it appears they are basically LC filters. 



I suppose it wouldnt hurt to look into MOV's for each cabinet, to add on top of my phase monitor relay, as long as I replace them on a schedule, like bi-annual.


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## JRaef (Mar 23, 2009)

BeerMaintenance said:


> Thanks everyone for the input. It's all about what I expected.
> 
> 
> 
> ...


I used to work for Sola who makes Power Conditioners and UPSs, so this was something I did a lot. Here is what I was meaning about knowing WHAT your problems are before making decisions. These are in order of increasing simplicity and cost, but also effectiveness;

If your problems are primarily transient SPIKES of extremely high voltage, you can use Surge Protective Devices (SPD), which are usually MOVs. But despite the name, SPDs do nothing for you regarding SWELLS or DIPS in line voltage. Only high peak fast rise-time SPIKES. If you want to use SPDs, get ones that have an indicator (usually an LED on each pole) that lets you know when it has sacrificed itself in the line of duty or for the best practice, a "surge counter" that lets you know how many "hits" it has received so that you can proactively replace it BEFORE it fails.

If your problems are primarily SWELLS or DIPS, then a Power Conditioner is what you need, but they do NOT protect against SPIKES.

If your SWELL/DIP problems also include INTERRUPTIONS of power for just a few cycles to a few seconds, then a Power Conditioner may not be enough, you need something more like a Dynamic System Compensator (DySC) device. But again, they don't help with SPIKES.

If the interruptions are BLACKOUTS that last minutes or more, then you need a UPS. But a UPS comes with the baggage of batteries, which means battery monitoring, maintenance, replacement, etc. etc., plus they usually operate with a bypass feature that saves the UPS by shunting SPIKES right around it!


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## BeerMaintenance (Apr 2, 2019)

Thanks for the reply


Sola makes good stuff! We have many of them in our cabinets. 



I think I might have misrepresented what my goal is. I want to protect the machinery. I am less worried about 24/7 uptime. 



A phase monitor would shut off the machine if there was a voltage dip or swell. That's all I want. Right now, when we see the lights flicker we run around frantically shutting everything down. It's always the machines that we don't shut off that have problems. It's weird, i know these power supplies are supposed to handle some fluctuation, but I think over time parts start to wear and they just cant handle it. 



Also, the phase monitor I am looking at record events, so it will be obvious when something happens and I can plan on replacing MOV's when that happens. 



I think the solution i am asking for is a combination of MOV suppression and the phase monitor relays. Noting that, do you think it would be smarter to add mov suppression to each cabinet, or just put larger ones on the main panels of the building?


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## gpop (May 14, 2018)

There is no real surprise that some machines shut down on a brown out where others do not as the power supply probably has some capacitance so it really depends on the load. The higher loaded ones will shut down where the lower loaded will not. 
As for mov's (tvss) they do not get old and wear out they simply short the spike which cause damage to them. All the tvss i have worked with have indicator lights to show they are functioning so a simple pm is to check to see if the lights are on. 

If you are using industrial grade equipment you will find its already full of movs (circuit boards have lots of them) you want to deal with any spikes before the equipment has to. blowing a tvss at the main is cheaper then blowing one inside a vfd.


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## Cow (Jan 16, 2008)

Is your company also pursuing damages against the power co?


You can do all you want on your side, but nothing will completely prevent the problems you're having if they're on the utility side. The only thing that will help alleviate the pain of this happening is knowing the utility is on the hook to pay for damages and downtime when THEIR power issues cost your company money.


One of our customers had so many incoming power issues, they hardwired in a power logger to their service that reports directly to their SCADA for trending.


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