EExd Motor - Surface Corrosion
EExd Motor - Surface Corrosion
(OP)
I’d like to know the opinions of those with specific knowledge of EX Hazardous Area Equipment on the following:-
How bad should surface corrosion on an EExd motor operating in an outdoors chemical enviroment be allowed to get before it affects its ability to operate safely?
We have several cast iron EExd motors which don’t have a lick of paint left on them & are covered in surface corrosion, although the surface corrosion does not appear to be deep. These motors are old & will probably be replaced with new ones rather than overhauled, my personal opinion is that this should be done sooner rather than later as the motors are out of compliance with BS EN 60079.
Thanks,
Alan
How bad should surface corrosion on an EExd motor operating in an outdoors chemical enviroment be allowed to get before it affects its ability to operate safely?
We have several cast iron EExd motors which don’t have a lick of paint left on them & are covered in surface corrosion, although the surface corrosion does not appear to be deep. These motors are old & will probably be replaced with new ones rather than overhauled, my personal opinion is that this should be done sooner rather than later as the motors are out of compliance with BS EN 60079.
Thanks,
Alan





RE: EExd Motor - Surface Corrosion
My concerns are with the affect on mechanical strentgh to the enclosure. Allso, will the temperature classification be infringed?
Thanks,
Alan
RE: EExd Motor - Surface Corrosion
www.themotorcover.com
RE: EExd Motor - Surface Corrosion
Thanks for your reply, but with flameproof equipment we are not allowed to obstruct the flanges.
Alan
RE: EExd Motor - Surface Corrosion
RE: EExd Motor - Surface Corrosion
RE: EExd Motor - Surface Corrosion
I notice your high input to threads & maybe your looking for a world record??
You obviously have limited knowledge on hazardous area electrical equipment,so my advice to you is GET REAL!!
I'm sure your advice in the past has been apreciated by a few.
Best Regards,
Alan
RE: EExd Motor - Surface Corrosion
RE: EExd Motor - Surface Corrosion
Hope this helps
Mark
RE: EExd Motor - Surface Corrosion
don't worry about surface corrosion on cast iron motors UNTIL you can see electrical cores or rotating parts or violent vibration.
I have a picture of a tin can type motor that was operating with half of the frame rusted away - running quite nicely. You could actually touch the rotor -- not recommended.
Keep the bearing lubrication clean and you should be OK.
PS: make sure the condenstate drain holes are free and properly placed.
RE: EExd Motor - Surface Corrosion
jbartos,
I notice your high input to threads & maybe your looking for a world record??
///This deviates from the eng-tips intent of this Forum.\\\
You obviously have limited knowledge on hazardous area electrical equipment,so my advice to you is GET REAL!!
///Please, notice that some threads are so demanding beyond eng-tips that they remain unanswered.\\\
I'm sure your advice in the past has been apreciated by a few.
///Some original postings seeking complete and perfect solutions in this Forum may be so-so satisfied with eng-tips only. I understand your frustrations.\\\
Best Regards,
Alan
RE: EExd Motor - Surface Corrosion
I think you missed the key phrase here 'HAZARDOUS AREA', my concerns are with the possiblity of a motor causing an explosion!!!
Thanks anyway for your interesting point.
Alan
RE: EExd Motor - Surface Corrosion
My conclusion............
You ARE a MAD Professor, have a beer & chill out!!
Regards,
Alan
RE: EExd Motor - Surface Corrosion
I think that your responses to jbartos are inappropriate and uncalled for. I like your advice though (but not in the context in which it was applied) and intend to follow it myself (in part at least) after work tonight.
As far as EEx d motors go, you have a couple of issues I guess. They always need to be strong enough to be able to withstand the forces generated from an internal explosion and most importantly, the integrity of the flame paths must be preserved. By the sound of it, if you have surface corrosion only, the strength may not be affected but it is possible that the flame paths are compromised. You would need to check this. The best thing would be to engage the services of a competent inspector (or the original motor manufacturer if possible) and have them check out the motors and give an opinion.
Personally, I do not like EEx d. If you are in a Zone 1 hazardous area, you could consider fitting EEx e replacement motors. Better still, if you are in a Zone 2 area you could go with EEx N motors.
RE: EExd Motor - Surface Corrosion
1. Donald G. Fink, H. Wayne "Standard Handbook for Electrical Engineers," 13th Edition (and perhaps some others too), McGraw-Hill, 1993, Section: Corrosion of Iron and Steel
on page 4-175
Electrochemical potentials may be hazardous since day one or minute one in in EX Hazardous Area.