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theripley

Member
theripley
Join Date
Jul 2008
Location
laguna
Posts
545
Hi,

I have inspected a carrier plating machine last week. Due to high air contamination brought about the low health risk consideration of the owner, RTUs located nearby the plating area are full of rust.

They are having trouble with their machine from time to time like motor overrunning. Has the rust contributed to this error? What will be the possible error I will encounter if the terminals of the RTU are "rusted".
 
I would assume that you mean Roof-Top Units (RTUs) for a HVAC system. Sometimes roof ventilator or exhaust fans are also called RTUs. In a corrosive environment with no periodic bearing lubrication, rust on motor shafts can cause pitting and bearing deterioriation (from running against rough rusty surfaces). Severe corrosion can lead to a variety of problems, but the motors may become overloaded due to excess friction and overheat, or cause the breakers or fuses to trip periodically.

Rust ON wire terminals is not usually a big problem (unless the wires have slip-on spade-type terminal lugs). If the environment is highly corrosive to certain brass and copper parts, then eventually the terminal screws and even the wires will corrode enough that the connection becomes "loose" and that leads to malfunctions, problems, and shut-downs.

For a spade terminal, if there is severe rust on the clamp, there will be a high-resistance path, which causes heating, which further loosens the terminal, which eventually lead to loss of that connection. This can shut down the equipment.

Rust BETWEEN terminals is a bad problem for electrical circuits. This condition can lead to short circuits, blown fuses, tripped breakers, or malfunctions.

PS: Ripley, long time, no see! Welcome back!
 
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Okie, it could be a remote terminal. If someone put those near a plating machine, then we got lots of other problems to worry about! It would be best to move the remote terminal units into a filtered and ventilated electrical room.
RTUs located nearby the plating area are full of rust.
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Because Erika said the RTUs contain rust, I AssUMed that the RTU has to be some device that can be opened up and inspected for rust. That would not apply to the Remote Terminal Controllers unless they are inside a separate corrosion-resistant enclosure. But then language is not precise.
 
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This is why I hate Acronyms.
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I am sure that Erika knows exactly what she means by "RTU". Trouble is, we don't, so cannot really provide much help until we know for sure.

In that Business Communications class that I took several years ago, the instructor would never have let a sentence with "RTU" in it pass by without making a bunch of bold red negative comments. Communications between humans is a two-way street. You not only have to know what you mean, but you have to know your audience or your correspondent well enough to know what they will THINK that you mean.
 
OkiePC said:
RTU: Remote Terminal Unit...not limited to HVAC, but any distributed control system could use them:
http://ab.rockwellautomation.com/programmable-controllers/datasite-rtu-controller#/tab2

http://www2.emersonprocess.com/en-US/brands/controlwave/scada-rtus/express/Pages/express.aspx
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Interestingly ......... that is also what the RTU stands for in Modbus RTU. Remote terminal unit.

Liam Moran said:
This is why I hate Acronyms.
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You and me both! They are a real PITA.


L D[AR2 said:
Mt :)
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You screwed up your acronym. They are supposed to be all CAPS.:ROFLMAO:
 
A guy I once worked with, who had worked at Intel previously,
Told me about the practice of making all kinds of technical descriptions into 'TLA's
(Three Letter Acronym). Anything that would not fit into this criteria became an 'ETLA'
(Extended Three Letter Acronym)
 
Interestingly ......... that is also what the RTU stands for in Modbus RTU. Remote terminal unit.
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Damian, can you imagine a way that a Modus Remote Terminal Unit could be "full of rust"? I find that a little hard to visualize. I can see one getting "rusty terminals" or corroded teminals, but find it unlikely that someone would remove the cover to find it "full of rust" (even if it did have rust inside). Probably it could be rusty or rusted on the outside, but most of us would not say that condition is full of rust.
 
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I am sorry for the acronym. But OkiePC is correct, I mean remote terminal units. The terminations in it are covered with rust, not the RTU (remote terminal unit) itself. This is what I meant in - "RTUs located nearby the plating area are full of rust." I never opened the RTU, like what Lancie1 was visualizing. Next time I will re-read it before posting.
 
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